tema 4: conversores con aislamiento galvánico · tema 4: conversores con aislamiento galvánico 1....
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Tema 4: Conversores con aislamiento galvánico
1. Modelo del transformador
1.1. Transformador ideal
1.2. Inductancia magnetizante
1.3. Inductancias de fugas y pérdidas
2. Conversores con aislamiento galvánico
2.1. Conversor Flyback
2.2. Conversor Forward
2.3. Conversor Push Pull
2.4. Conversor Half Bridge
2.5. Conversor Full Bridge
1
1.1. Modelo del transformador. Transformador ideal
Ley de Ampère:Ley de Ampère:
02211 ininE f d id l 0
Ley de Faraday:
En un transformador ideal 0
Fundamentals of Power Electronics, second edition”. R. W: dtd
nv
nv
2
2
1
1
Erickson, D. Maksimovic. Springer (Kluwer Academic Press), 2001.
dtnn 21
Otras relaciones:lAl
Reluctancia:
Inductancia: )linealrelacióno(suponiend; LindndL
Para cada bobinado:
Inductancia: )linealrelación o(suponiend ; Lindi
ndi
L
n ni
2nL
2
En un transformador ideal, la L asociada a cada bobinado es infinita
1.1. Modelo del transformador. Transformador ideal
3
1.1. Modelo del transformador. Transformador ideal
4
1.2. Modelo del transformador. Inductancia magnetizante
5
1.2. Modelo del transformador. Inductancia magnetizante
6
1.2. Modelo del transformador. Inductancia magnetizante
7
1.3. Modelo del transformador. Inductancias de fugas y pérdidas
8
1.3. Modelo del transformador. Inductancias de fugas y pérdidas
9
1.3. Modelo del transformador. Inductancias de fugas y pérdidas
10
Switching DC Power Supply: Multiple Outputs2. Conversores con aislamiento galvánico
• In most applications, several dc voltages are required, possibly electrically isolated from each other
11
Flyback Converter2.1. Conversor Flyback
• Derived from buck‐boost
12
Flyback Converter2.1. Conversor Flyback
• Switch on and off states (assuming incomplete core demagnetization)
13
Flyback Converter2.1. Conversor Flyback
• Switching waveforms (assuming incomplete core demagnetization)
14
2.1. Conversor Flyback
15
2.1. Conversor Flyback
40V
Vv 22 iVNv t
0V
1 inVv 1
2 inVN
v
oVv 2oVNNv
2
11
ton
toff
6.0AV(L1:1)- V(L1:2) V(L2:1)- V(L2:2) V(R1:1)- V(R1:2)
-40V
inM
s
MM V
LDTdttv
Li )(1
1
I(L1)+2* I(L2)5.0A
5.5A
SEL>>
MM LL
012
1 osM
inM
s VTDNL
NVLDT
4.0A
8.0A
ton
t
1iiM 02 i
0i 2 iNi
Time
50.00ms 50.01ms 50.02ms 50.03ms 50.04msI(L1) I(L2)
0A
toff 01 i 21
iN
iM
dttvL
i )(12
22
Time
(verde) 1v (rojo) 2v (azul) oVArriba:
En medio: (azul) Mi
2
MLNNL 2
1
22
2
Abajo: (verde) 1i (rojo) 2i
16
Forward Converter2.2. Conversor Forward (idealizado)
• Derived from Buck; idealized to assume that the transformer is ideal (not possible in practice)( p p )
17
2.2. Conversor Forward (idealizado)
L2L1 R1Vin
D1
Dideal
L3
200u
{LM*N2N1*N2N1}{LM} 1020 C1500u
00
D2Dideal
K K1
COUPLING = 1K_Linear
L1 = L1V1V1 = 0
PARAMETERS:N2N1 = 2f s = 50k
0
M1Rof f{Rof f } L1 = L1
L2 = L2
V1
TD = 0
TF = {1/(1000*f s)}PW = {Duty /f s}PER = {1/f s}
V1 = 0
TR = {1/(1000*f s)}
V2 = 10 Duty = 0.4LM = 1mRof f = 1meg
0 0
Mbreakn{Rof f }
PER = {1/f s}
18
1 inVv 1
22 inV
NNv ton
2.2. Conversor Forward (idealizado)
toff
oinL VVNNv
1
2
oL Vv
ton Lii 2
oL
21
21 i
NNii M
toff 021 ii
inM
s
MM V
LDTdttv
Li )(1
1MM
(azul) Lv (rojo) oVArriba:
En medio: (azul) 1i (rojo) 2i (verde) Li
Abajo: (azul) Mi
19
Forward Converter: in 2.2. Conversor Forward (en la práctica)
Practice
• Switching waveforms (assuming complete core demagnetization)
20
2.2. Conversor Forward (en la práctica)
L4
L2
D1
DidealL1Vin R1
L3 {LM*N3N1*N3N1}L4
10uH
{LM*N2N1*N2N1}D2Dideal
{LM}201
C1500u
0 D3
K K1
COUPLING = 1K_Linear
PARAMETERS:N2N1 = 0.5f s = 100k
M1
0D3Dideal
0R2
L1 = L1L2 = L2L3 = L3
f s 100kDuty = 0.5LM = 3.2mRof f = 1megN3N1 = 0.2
V1
TD = 0
TF = {1/(1000*f s)}PW = {Duty /f s}
V1 = 0
TR = {1/(1000*f s)}
V2 = 10 Mbreakn
00
{Rof f }
PW {Duty /f s}PER = {1/f s} 00
21
2.2. Conversor Forward (en la práctica)
ODCL Ii ,
ton Lii 2 21
21 i
NNii M
OC,
03 i
inM
s
MMMMAX V
LDTdttv
Lii )(1
1
3
MM LL
toff 021 ii 31
3 iNNiM
MMAXMAX iNNi
3
13
1
DNN
Tt
S
M
1
3
(azul) LiArriba:
Abajo: (azul) Mi
(verde) 1i (rojo) 2i
(rojo) 3i
22
PWM to Regulate Output2.3. Conversor Push-Pull
• Basic principle is the same as discussed in Chapter 8
23
Push‐Pull Inverter2.3. Conversor Push-Pull
k i d b bl• Leakage inductances become a problem24
3.3. Conversor Push-Pull
L5D1 DidealR2
C1
L1{LM}
10uH
R1
1
L2{LM*N2N1*N2N1}
D1
1e10
I
500u 1
L3 L4{ * * }
VinI
I
M1
{LM} {LM*N2N1*N2N1}
D2
Dideal VinM2
R3
1e10I
I
MbreaknPARAMETERS:N2N1 = 0.5f s = 100kDuty = 0.3
K K1
COUPLING = 1K_Linear
L1 = L1
Vin120
Mbreakn
Vc1 Vc2I
LM = 3.2mRof f = 1megN3N1 = 0.2
L2 = L2L3 = L3L4 = L4
00 0
V1
TD = 0
V1 = 0
TR = {1/(1000*f s)}
V2 = 10V2
TD = {0.5/f s}
V1 = 0
TR = {1/(1000*f s)}
V2 = 10
Vc1 Vc2
TF = {1/(1000*f s)}PW = {Duty /f s}PER = {1/f s} 0
TF = {1/(1000*f s)}PW = {Duty /f s}PER = {1/f s} 0
25
2.3. Conversor Push-Pull
26
Half‐Bridge Converter2.4. Conversor Half Bridge
i d f k• Derived from Buck27
Full‐Bridge Converter2.5. Conversor Full Bridge
• Used at higher power levels (> 0.5 kW )
28
Core Utilization in Various Converter Topologies
• At high switching frequencies, core losses limit excursion of flux density
29
Implementing Electrical Isolation in the Feedback
Loop
• Two ways are shown• Two ways are shown
30
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