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1
WB2414-Mechatronic System Design 2013-2014 1DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 6
Profir RHMunnig SchmidtMechatronic System Design
Power electronics
WB2414-Mechatronic System Design 2013-2014 2DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 2
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
2
WB2414-Mechatronic System Design 2013-2014 3DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 3
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 4DelftUniversity ofTechnology
Electronics in mechatronics
Analogue control Sensing
Power conversionADDA
3
WB2414-Mechatronic System Design 2013-2014 5DelftUniversity ofTechnology
The amplifier and actuator have to deliver a real force F at best equal to the control force
F
WB2414-Mechatronic System Design 2013-2014 6DelftUniversity ofTechnology
The task of the power amplifier is that of a controller
bullControlling the characteristics of an electromagnetic actuatormotor by controlling the actuator‐input signal the voltage and current
bullDistinguishing items
bull Power capability (Voltage Current)
bull Dynamic properties like stability and control bandwidth
bull Low or high output impedance (voltage or current source output)
bull Efficiency (Power dissipation)
bull Linearity full range proportional output value (freedom of distortion)
4
WB2414-Mechatronic System Design 2013-2014 7DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 7
Power Capability is directly visible
bullHigh voltage and current levels limit small size (solid‐state) integration
bull Discrete Components
bull Switching relays
bull Thermal Control
bull Risk of interference by strong magnetic and electric fields (EMC)
WB2414-Mechatronic System Design 2013-2014 8DelftUniversity ofTechnology
Dynamic Properties in two directions
bull Amplifiers are part of the position feedback loop
bull Delay for instance from latency in a digitally controlled amplifier will reduce
stability
bull Also the bandwidth how quickly can the current follow a setpoint change
(HF behaviour) is related to a negative impact on the phase
bull The dynamic load from the actuator(LRC) will impact stability of the
amplifier
Amplifier
Actuator
5
WB2414-Mechatronic System Design 2013-2014 9DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 9
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
WB2414-Mechatronic System Design 2013-2014 10DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 10
Efficiency
bull An amplifier converts a supply voltage current into a motor
voltagecurrentbull A difference of voltage means power loss unlesshellipbull A difference in current requires energy buffering in capacitors or
batteries
bull Switched modePWM amplifiers reduce dissipation but have other
special properties that have to be known
6
WB2414-Mechatronic System Design 2013-2014 11DelftUniversity ofTechnology
out
in
VV
Amplifiers for electromagnetic actuators 11
Linearity distortion
Momentary gaindepends on value of output
outV
inV
maxV
maxVClipping example
WB2414-Mechatronic System Design 2013-2014 12DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 12
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
2
WB2414-Mechatronic System Design 2013-2014 3DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 3
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 4DelftUniversity ofTechnology
Electronics in mechatronics
Analogue control Sensing
Power conversionADDA
3
WB2414-Mechatronic System Design 2013-2014 5DelftUniversity ofTechnology
The amplifier and actuator have to deliver a real force F at best equal to the control force
F
WB2414-Mechatronic System Design 2013-2014 6DelftUniversity ofTechnology
The task of the power amplifier is that of a controller
bullControlling the characteristics of an electromagnetic actuatormotor by controlling the actuator‐input signal the voltage and current
bullDistinguishing items
bull Power capability (Voltage Current)
bull Dynamic properties like stability and control bandwidth
bull Low or high output impedance (voltage or current source output)
bull Efficiency (Power dissipation)
bull Linearity full range proportional output value (freedom of distortion)
4
WB2414-Mechatronic System Design 2013-2014 7DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 7
Power Capability is directly visible
bullHigh voltage and current levels limit small size (solid‐state) integration
bull Discrete Components
bull Switching relays
bull Thermal Control
bull Risk of interference by strong magnetic and electric fields (EMC)
WB2414-Mechatronic System Design 2013-2014 8DelftUniversity ofTechnology
Dynamic Properties in two directions
bull Amplifiers are part of the position feedback loop
bull Delay for instance from latency in a digitally controlled amplifier will reduce
stability
bull Also the bandwidth how quickly can the current follow a setpoint change
(HF behaviour) is related to a negative impact on the phase
bull The dynamic load from the actuator(LRC) will impact stability of the
amplifier
Amplifier
Actuator
5
WB2414-Mechatronic System Design 2013-2014 9DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 9
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
WB2414-Mechatronic System Design 2013-2014 10DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 10
Efficiency
bull An amplifier converts a supply voltage current into a motor
voltagecurrentbull A difference of voltage means power loss unlesshellipbull A difference in current requires energy buffering in capacitors or
batteries
bull Switched modePWM amplifiers reduce dissipation but have other
special properties that have to be known
6
WB2414-Mechatronic System Design 2013-2014 11DelftUniversity ofTechnology
out
in
VV
Amplifiers for electromagnetic actuators 11
Linearity distortion
Momentary gaindepends on value of output
outV
inV
maxV
maxVClipping example
WB2414-Mechatronic System Design 2013-2014 12DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 12
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
3
WB2414-Mechatronic System Design 2013-2014 5DelftUniversity ofTechnology
The amplifier and actuator have to deliver a real force F at best equal to the control force
F
WB2414-Mechatronic System Design 2013-2014 6DelftUniversity ofTechnology
The task of the power amplifier is that of a controller
bullControlling the characteristics of an electromagnetic actuatormotor by controlling the actuator‐input signal the voltage and current
bullDistinguishing items
bull Power capability (Voltage Current)
bull Dynamic properties like stability and control bandwidth
bull Low or high output impedance (voltage or current source output)
bull Efficiency (Power dissipation)
bull Linearity full range proportional output value (freedom of distortion)
4
WB2414-Mechatronic System Design 2013-2014 7DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 7
Power Capability is directly visible
bullHigh voltage and current levels limit small size (solid‐state) integration
bull Discrete Components
bull Switching relays
bull Thermal Control
bull Risk of interference by strong magnetic and electric fields (EMC)
WB2414-Mechatronic System Design 2013-2014 8DelftUniversity ofTechnology
Dynamic Properties in two directions
bull Amplifiers are part of the position feedback loop
bull Delay for instance from latency in a digitally controlled amplifier will reduce
stability
bull Also the bandwidth how quickly can the current follow a setpoint change
(HF behaviour) is related to a negative impact on the phase
bull The dynamic load from the actuator(LRC) will impact stability of the
amplifier
Amplifier
Actuator
5
WB2414-Mechatronic System Design 2013-2014 9DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 9
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
WB2414-Mechatronic System Design 2013-2014 10DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 10
Efficiency
bull An amplifier converts a supply voltage current into a motor
voltagecurrentbull A difference of voltage means power loss unlesshellipbull A difference in current requires energy buffering in capacitors or
batteries
bull Switched modePWM amplifiers reduce dissipation but have other
special properties that have to be known
6
WB2414-Mechatronic System Design 2013-2014 11DelftUniversity ofTechnology
out
in
VV
Amplifiers for electromagnetic actuators 11
Linearity distortion
Momentary gaindepends on value of output
outV
inV
maxV
maxVClipping example
WB2414-Mechatronic System Design 2013-2014 12DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 12
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
4
WB2414-Mechatronic System Design 2013-2014 7DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 7
Power Capability is directly visible
bullHigh voltage and current levels limit small size (solid‐state) integration
bull Discrete Components
bull Switching relays
bull Thermal Control
bull Risk of interference by strong magnetic and electric fields (EMC)
WB2414-Mechatronic System Design 2013-2014 8DelftUniversity ofTechnology
Dynamic Properties in two directions
bull Amplifiers are part of the position feedback loop
bull Delay for instance from latency in a digitally controlled amplifier will reduce
stability
bull Also the bandwidth how quickly can the current follow a setpoint change
(HF behaviour) is related to a negative impact on the phase
bull The dynamic load from the actuator(LRC) will impact stability of the
amplifier
Amplifier
Actuator
5
WB2414-Mechatronic System Design 2013-2014 9DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 9
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
WB2414-Mechatronic System Design 2013-2014 10DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 10
Efficiency
bull An amplifier converts a supply voltage current into a motor
voltagecurrentbull A difference of voltage means power loss unlesshellipbull A difference in current requires energy buffering in capacitors or
batteries
bull Switched modePWM amplifiers reduce dissipation but have other
special properties that have to be known
6
WB2414-Mechatronic System Design 2013-2014 11DelftUniversity ofTechnology
out
in
VV
Amplifiers for electromagnetic actuators 11
Linearity distortion
Momentary gaindepends on value of output
outV
inV
maxV
maxVClipping example
WB2414-Mechatronic System Design 2013-2014 12DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 12
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
5
WB2414-Mechatronic System Design 2013-2014 9DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 9
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
WB2414-Mechatronic System Design 2013-2014 10DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 10
Efficiency
bull An amplifier converts a supply voltage current into a motor
voltagecurrentbull A difference of voltage means power loss unlesshellipbull A difference in current requires energy buffering in capacitors or
batteries
bull Switched modePWM amplifiers reduce dissipation but have other
special properties that have to be known
6
WB2414-Mechatronic System Design 2013-2014 11DelftUniversity ofTechnology
out
in
VV
Amplifiers for electromagnetic actuators 11
Linearity distortion
Momentary gaindepends on value of output
outV
inV
maxV
maxVClipping example
WB2414-Mechatronic System Design 2013-2014 12DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 12
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
6
WB2414-Mechatronic System Design 2013-2014 11DelftUniversity ofTechnology
out
in
VV
Amplifiers for electromagnetic actuators 11
Linearity distortion
Momentary gaindepends on value of output
outV
inV
maxV
maxVClipping example
WB2414-Mechatronic System Design 2013-2014 12DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 12
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
7
WB2414-Mechatronic System Design 2013-2014 13DelftUniversity ofTechnology
First a few definitions while keepingldquorealrdquoelectronics to the bare minimum
bullVoltage and current sourcebullOhmrsquos lawbullResistorsbullCapacitorsbullInductors
WB2414-Mechatronic System Design 2013-2014 14DelftUniversity ofTechnology
bull An ideal voltage source is a circuit element where the voltage across it is independent of the load (current) It has a zero source impedance It can be replaced by a short circuit when the influence of another electric source in the circuit is to be determined
bull An ideal current source is a circuit element where the current through it is independent of the load (voltage) It has an infinite source impedance It can be replaced by an open circuit when the influence of another electric source in the circuit is to be determined
bull Both do not exist in reality but only in physical models of circuits In reality one can only approximate its behaviour
Ideal voltage and current sources
+- +- +-
+- +- +-
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
8
WB2414-Mechatronic System Design 2013-2014 15DelftUniversity ofTechnology
Ohmrsquos law the definition of impedance
Source
Impedance (Z)
+
-
Current (I)
Voltage(V)
V
V IR IR
22 V
P IV I RR
Power in Watt (W)
( )( ) ( ) ( ) ( )
( )
V fV f I f Z f I f
Z f
Dynamic impedance Z(f)
WB2414-Mechatronic System Design 2013-2014 16DelftUniversity ofTechnology
Practical resistors
bull Resistor size is determined by the power dissipationbull (Wirewound) resistors have parasitic self inductance and
capacitancebull Range from mΩ to GΩ
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
9
WB2414-Mechatronic System Design 2013-2014 17DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
Self‐inductance of windings is related to induced magnetic field
Induced voltage by a changing magnetic field (Faraday)
wtwL e
2wt
d d
d d
d
d
w
IV n L
t
nI nL n n
I I
t
I
t
IwF
wf
d
d
t
Fmicro-E
+
_
L
2
d
d
IV L
t
nL
=
=Acirc
Inductor L with n windings
WB2414-Mechatronic System Design 2013-2014 18DelftUniversity ofTechnology
First dynamic impedance the coil or Inductor (symbol L from Lenz)
w( )
( ) ( )
( ) ( )c
d dIV t n L
dt dtV t V j LI
VZ j L
I
bull For AC the voltage leads the current
with 90degI
V+
_
L
Fourier transform d
dj
t
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
10
WB2414-Mechatronic System Design 2013-2014 19DelftUniversity ofTechnology
Power and energy in an inductor
1 1 1
0 0
pp p p
p p p p
2L L 10
sp
( )) )
( )) cos ) sin
sin cos ) average 0
d 1( )d ( )
( ) ( (
d ( )dd 2
( (
05 sin(2
(compare
t t I
t t
V
j L
VVt t I
j L L
t t
V j LI I
V V I I
P t
IE P t t I t L t L I t I LI
I V I V
E
t
2
ring 05 )kF
I
V+
_
L
bull The current as function of the voltage equals
bull The power equals
bull And the momentary energy equals
WB2414-Mechatronic System Design 2013-2014 20DelftUniversity ofTechnology
Practical Inductorsbull Inductor size is determined by the selfinductance and the
currentbull Inductors have parasitic capacitance resistance and eddy
current lossesbull Range from microH to several mH
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
11
WB2414-Mechatronic System Design 2013-2014 21DelftUniversity ofTechnology
A capacitor is storing electrical energy in charge on two separated plates with distance D and surface A
bull The capacitance is
bull In vacuum the permittivity ε0 is
bull The charge is
bull With AC the current leads the voltage by 90deg
Second dynamic impedance the Capacitor
-120 2
0
1885 10
c
q CV
2 2
p p p p kinsi
1( ) ( ) ( ) ( ) =
05 sin(2 (comn cos ) averag pe 0 05 0e 5ar )
dQ dV VI t C I t I j CV Z
dt dt I j C
P V I V It t t E CV mE v
CA
d
WB2414-Mechatronic System Design 2013-2014 22DelftUniversity ofTechnology
Practical Capacitorsbull Capacitor size is determined by the Capacitance and currentbull Capacitors have parasitic self inductance and resistancebull Range from 1pF (ceramic) to ~ gt 1 F (electrolytic super caps)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
12
WB2414-Mechatronic System Design 2013-2014 23DelftUniversity ofTechnology
So do you recognise these elements
WB2414-Mechatronic System Design 2013-2014 24DelftUniversity ofTechnology
These parts are used to make filters forthe output of switching-mode amplifiers
bullVoltage dividers or attenuators
bull1st order low‐pass filters
bull2nd order low‐pass filters
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
13
WB2414-Mechatronic System Design 2013-2014 25DelftUniversity ofTechnology
A voltage divider
i
1 2
i 2o 2
1 2
VI
Z Z
V ZV I Z
Z Z
WB2414-Mechatronic System Design 2013-2014 26DelftUniversity ofTechnology
Discussion
bullDesign a first‐order low pass filter for 1000Hz
bull Use voltage dividerbull Choose best suitable components
bull Determine frequency response
bull Determine component values
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
14
WB2414-Mechatronic System Design 2013-2014 27DelftUniversity ofTechnology
1st order low-pass with capacitor
o 2
i 1 2
V Z
V Z Z
o
i
1
( ) ( )1
1 1
1 1
f
V j CG
V Rj C
j RC j
1 2
1 and Z R Z RC
j C
Corner frequency
0 0
1 12 f
RC
WB2414-Mechatronic System Design 2013-2014 28DelftUniversity ofTechnology
Questione prosciutto
bull Will this work with power transfer
from input to output
bull So what must be avoided
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
15
WB2414-Mechatronic System Design 2013-2014 29DelftUniversity ofTechnology
1st order low-pass with inductor without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
( ) ( )
1 1
11
f
V RG
V R j
jj
L
L
R
1 2 and ZL
L RZR
j
Corner frequency
0 0
12
Rf
L
Z2 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 30DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 30
A second order passive low pass filter without series resistor
o 2
i 1 2
V Z
V Z Z
o
i
22
20
1
( ) ( )1
1 1
1)
( 1
f
V j CG
V j Lj C
j LC
1 2 0
1 1 Z j L Z
j C LC
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
16
WB2414-Mechatronic System Design 2013-2014 31DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 31
A second order low pass filter with parallel damping
o 2 3
1i 1 2 31
2 3 2 3
1 1
1 11 1
V Z ZZV Z Z Z
ZZ Z Z Z
o
i
2 22
2 20 0 0 0
1( ( )
11
1 1 1
2( 1) 1
)
1
f
VG
Vj L j C
R
L j jj LC jR Q
1 2 3
0
1 Z
1 1 1
2 2
Z j L Z Rj C
L CQ R
R C LLC
Z3 represents the power in the load
WB2414-Mechatronic System Design 2013-2014 32DelftUniversity ofTechnology
Mechatronic system design WB2414 R Munnig Schmidt 32
A second order low pass filter with parallel damping
2
20 0
1( )
1fG
jQ
Q=1
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
17
WB2414-Mechatronic System Design 2013-2014 33DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 33
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 34DelftUniversity ofTechnology
Group discussion
bull Discuss difference of voltage and current control to drive an
actuator in mechatronic systems
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
18
WB2414-Mechatronic System Design 2013-2014 35DelftUniversity ofTechnology
A current source output will cancel effects of the self inductance and motion EMF
a ma m LR
ddI
VV V tR
IR
V LVV
R
With a voltage source the current is
With a Lorentz actuator a current source will create a direct conversion from the setpoint(control force) to actuator force
WB2414-Mechatronic System Design 2013-2014 36DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 36
Low or high output impedance of an Amplifier
bull Low impedance (voltage source output)
bull When damping is necessary
bull Loudspeakers
bull Feedforward (no feedback)
bull High impedance (current source output)bull When the currentforce has to be independent of the movement
(Lorentz actuators)
bull When the currentforce has to be independent of the self inductance
(servo systems)
Actuator
Ra
La
Ua
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
19
WB2414-Mechatronic System Design 2013-2014 37DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 37
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 38DelftUniversity ofTechnology
Linear power amplifiers
bull A linear power amplifier is nothing else than a powerful version of
a small signal amplifier
bull It is often designed like an operational amplifier with high‐power
output stage
bull So it starts with the basic Op‐amp
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
20
WB2414-Mechatronic System Design 2013-2014 39DelftUniversity ofTechnology
The analogue (operational) amplifier is an integrated feedback-controlled system
Complementary sensitivity
a oaoo
i ao af a fa f
a o
1 1
1 1GGV
V G G GGG
WB2414-Mechatronic System Design 2013-2014 40DelftUniversity ofTechnology
1 Input currents in the Op‐amp are zero
2 With negative feedback the output will do whatever it can to keep the negative input voltage equal to the positive input voltage
Modelling1 Verify that there is Negative Feedback
2 Calculate the voltage on the positive input3 Calculate the voltage at the output by applying rule 1 and 2 which means that
it generates the same voltage over the feedback path at the negative input as
was calculated in step 2
Main guidelines of determining the behaviour of an ideal Op-Amp circuit
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
21
WB2414-Mechatronic System Design 2013-2014 41DelftUniversity ofTechnology
What source is the output of this amplifier
Voltage or Current source What is controlled
WB2414-Mechatronic System Design 2013-2014 42DelftUniversity ofTechnology
Transconductance amplifier has a current source output
bull Converts an input setpoint
voltage into an output current by measuring the current through the load and controlling
the output of the amplifier to keep the current proportional to the setpoint
bull Used for driving electromagnetic actuators
bull Rcs measures current but thereis a better way without voltage
drop
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
22
WB2414-Mechatronic System Design 2013-2014 43DelftUniversity ofTechnology
Lossless current sensing for high current levels and improved efficiency
Amplifiers for electromagnetic actuators 43Hall sensor for magnetic field
Active compensation of magnetic field generated by current Ip
magnetic field
WB2414-Mechatronic System Design 2013-2014 44DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 44
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
23
WB2414-Mechatronic System Design 2013-2014 45DelftUniversity ofTechnology
Ideal and real properties of regular (non-power) operational amplifiers
Parameter Ideal Op Amp
OPA27 Unit
DC Open loop Gain (G0) infin 120 (=106) dB
Input impedance (Zin) infin 6106 Ω
Output impedance (Zout) 0 70 Ω
Input offset voltage (Vos) 0 lt 25 μV
Temp coeumlff of Vos (γ) 0 06 μVoC
Input bias current (Ib) 0 40 nA
Input offset current (Ios) 0 10 nA
Gain bandwidth product infin 5106 Hz
Common mode rejection ratio (CMRR)
infin 120 (=106) dB
WB2414-Mechatronic System Design 2013-2014 46DelftUniversity ofTechnology
Dynamic limitations of standard Op-Amp
Many capacitors
And with a power amplifier they are large
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
24
WB2414-Mechatronic System Design 2013-2014 47DelftUniversity ofTechnology
Often a dominant pole is applied ~1 Hz to compensate several poles
Gain‐bandwidth product is constant over this line
WB2414-Mechatronic System Design 2013-2014 48DelftUniversity ofTechnology
Discussion
What is the bandwidth of this amplifier
bull Gain BW product = 106
bull R1=100
bull R2=10000
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
25
WB2414-Mechatronic System Design 2013-2014 49DelftUniversity ofTechnology
What is the impact of the dominant pole on the current source output impedance
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull Cut the loop just before the minus input
cfbl a
o a cfb a o
oo l
o
G
G G
VG
V
V V I
V
IZ G
AmplifierinV
oVcfb 0V I
oISimplified
V
V
I to V
aG
WB2414-Mechatronic System Design 2013-2014 50DelftUniversity ofTechnology
bull The higher the loop‐gain the
better the current is controlled so the higher is the output impedance
bull The loopgain and output impedance is inverse
proportional to the frequency
bull So what is the character of the
output impedance
What is the impact of the dominant pole on the current source output impedance
inV
oV
oIo lZ G
cfb 0V II to V
AmplifierV
V aG
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
26
WB2414-Mechatronic System Design 2013-2014 51DelftUniversity ofTechnology
51
The actuator inductance creates an additional pole (RL)
This creates stability issues and a potential resonance
WB2414-Mechatronic System Design 2013-2014 52DelftUniversity ofTechnology
52
The actuator inductance creates an additional pole (RL)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
27
WB2414-Mechatronic System Design 2013-2014 53DelftUniversity ofTechnology
WB2414 Mechatronic system design 53
Phase compensation can help the stability
But that changes the closed loop response which can be OK for rejection of resonances
Conclusion One has to ldquoshaperdquo the feedback loop inside the amplifier towards the application
WB2414-Mechatronic System Design 2013-2014 54DelftUniversity ofTechnology
Extreme example of loopshaping voltage source audio amplifier
Two internal poles
Two external poles (output filter)
Four internal zeros plus one pole
‐2
‐4
‐1
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
28
WB2414-Mechatronic System Design 2013-2014 55DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 55
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 56DelftUniversity ofTechnology
Main drawback of a linear non-switchingpower output stage is dissipation of energy
Issue 1 High supply voltage is needed with an inductive load
a R m L m
3
3
max mmax
d
dJerk
d
d
d dd
d
IV V V
t
x I
t
V V IR L
I
tI
V V LRt
=
=
I x
V x
x
Jerk
Snap
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
29
WB2414-Mechatronic System Design 2013-2014 57DelftUniversity ofTechnology
Issue 2 Current and voltage are not in phase
bull In case of pure inductor
d
dˆsin
ˆd( sin ) d(sin )ˆ ˆ ˆ ˆcos d d
I
t
I I t
I t tV I V t V LI
t t
V L
L L
WB2414-Mechatronic System Design 2013-2014 58DelftUniversity ofTechnology
Discussion
What happens at t1
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
30
WB2414-Mechatronic System Design 2013-2014 59DelftUniversity ofTechnology
Negative current with positive voltage
lloss p oo oP VII V V
4 quadrant operation any combination of +-V and I
fi t1
V
I +
+
_
_
WB2414-Mechatronic System Design 2013-2014 60DelftUniversity ofTechnology
4 Quadrant power delivery
4 quadrant operation Any combination of +-V and I
V
I +
+
_
_
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
31
WB2414-Mechatronic System Design 2013-2014 61DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 61
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
WB2414-Mechatronic System Design 2013-2014 62DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier) depending on duty cycle
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
32
WB2414-Mechatronic System Design 2013-2014 63DelftUniversity ofTechnology
PWM or switched mode power conversion
bullA switch does not dissipate energybull Switches can only create squarewave signals (onoff) when switching fast
bull Low pass filtering gives the average value (Fourier)bull L‐C filtering is non‐dissipative
WB2414-Mechatronic System Design 2013-2014 64DelftUniversity ofTechnology
Pulse width (duty cycle) modulation
Amplifiers for electromagnetic actuators 64
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
33
WB2414-Mechatronic System Design 2013-2014 65DelftUniversity ofTechnology
Power switches the MOSFET
Amplifiers for electromagnetic actuators 65
N-channelElectrons as charge carriers
WB2414-Mechatronic System Design 2013-2014 66DelftUniversity ofTechnology
Switching cycle step 1
Amplifiers for electromagnetic actuators 66
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
34
WB2414-Mechatronic System Design 2013-2014 67DelftUniversity ofTechnology
Switching cycle step 2
Amplifiers for electromagnetic actuators 67
WB2414-Mechatronic System Design 2013-2014 68DelftUniversity ofTechnology
Switching cycle step 3
Amplifiers for electromagnetic actuators 68
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
35
WB2414-Mechatronic System Design 2013-2014 69DelftUniversity ofTechnology
Switching cycle step 4
Amplifiers for electromagnetic actuators 69
WB2414-Mechatronic System Design 2013-2014 70DelftUniversity ofTechnology
Change of duty cycle Rload=5 Ω
Amplifiers for electromagnetic actuators 70
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
36
WB2414-Mechatronic System Design 2013-2014 71DelftUniversity ofTechnology
Charge pumping with unipolar output voltage
Amplifiers for electromagnetic actuators 71
Io flows from positive supply and from negative supplyPositive supply delivers power Negative supply receives power
WB2414-Mechatronic System Design 2013-2014 72DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 72
In a bridge configuration these currents are balanced
Power supply to load and inductors
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
37
WB2414-Mechatronic System Design 2013-2014 73DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 73
In a bridge configuration these currents are balanced
Power recovery from inductors
WB2414-Mechatronic System Design 2013-2014 74DelftUniversity ofTechnology
Amplifiers for electromagnetic actuators 74
Contents
bullPower electronics whatrsquos so special about it
bullPassive (power) electronic filters
bull Why so many inductors
bullCurrent or voltage source amplifier output
bull Actuator determined spec
bull Linear dissipative power amplifiers
bullDynamic impact of power amplifiers
bull Stability and frequency dependent characteristics
bull Switched mode power conversion
bull 4 quadrant power delivery
bull PWM Amplifiers
bull 3‐phase amplifiers
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
38
WB2414-Mechatronic System Design 2013-2014 75DelftUniversity ofTechnology
Three phase actuators need threecurrents
Sum of currents is zero
WB2414-Mechatronic System Design 2013-2014 76DelftUniversity ofTechnology
Three phase amplifier concept
Question What goes wrong when all three amplifiers have a current‐source output
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
39
WB2414-Mechatronic System Design 2013-2014 77DelftUniversity ofTechnology
Three phase amplifier output stage
No charge pumping and three phase with three MOSFET pairsOne of the amplifiers is voltage controlled to keep the average voltage at zero
WB2414-Mechatronic System Design 2013-2014 78DelftUniversity ofTechnology
Mechatronic system design
Mechatronic system design wb2414‐20132014
Course part 7
Profir RHMunnig SchmidtMechatronic System Design
How to connect
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)
40
WB2414-Mechatronic System Design 2013-2014 79DelftUniversity ofTechnology
The V-model of Systems EngineeringFunctional requirements Realized functions
Detailed design Timeline
System design
Subsystem design
Feedback loops
WB2414-Mechatronic System Design 2013-2014 80DelftUniversity ofTechnology
Main items to keep in mind
bull ldquoNestingrdquo
bull Lower parts are nested inside higher parts in the V model
bull Many nested control systems (amplifier current motion)
bull All influence eachother in two directions
bull Mechanical dynamics determine the final performancebull Bandwidth limited by eigenmodes
bull Power Amplifier and actuator are one
bull Control force to real force
bull Optimal tuning in dynamics and electrical properties
bull Motion Control is both the connecting lead as the polishing layer
bull Model based feedforward to almost perfection
bull All physical systems (plant=ADDA amplifier actuator mechanics
sensor) to be included in model
bull Feedback for robustness (to be minimised by feedforward)