research on hybrid modulation strategies on the hybrid
TRANSCRIPT
RESEARCH ON HYBRID MODULATION STRATEGIES ON THE H-BRIDGE TOPOLOGY OF MULTILEVEL INVERTER
PROJECT MEMBERS
S.Amanullah 50408105005
R.Balamurugan 50408105013
A.Manivasagan 50408105045
M.Sai natarajan 50408105071
GUIDED BY: Mr.C.R.Balamurugan, Senior Lecturer(EEE)
Main Applications of MLI
Active Power Filters Static Var Compensator Machine Drives for Sine wave Current
Applications HEV Solar PV modules
Advantages
Devices of lower rating can be used thereby enabling the schemes to be used for high voltage applications.
Reduced total harmonic distortion (THD). Better Performance Less dv/dt Stresses Less Stresses in the Bearings of the Motor Lower switching frequencies can be used
and hence reduction in switching losses.
Disadvantages
Switching devices required is proportional to Number of Levels
Control strategy is difficult When the number of levels Increases design is
Complicated The number of isolated DC-links are more
compared to a two-level inverter. Power bus structure and hence the control
schemes become complex as the number of levels increases.
Decrease in Reliability
Objective
To Perform Hybrid Modulation Strategies on the H-Bridge Topology and Hybrid Topology of the Multilevel Inverter
To Analyze the Different Modulation techniques In MATLAB and to Choose the technique which is Efficient for Hardware Implementation
Operation of MLI by Switch
Conventional MLI topologies
DCMLI(MPC or NPC) FCMLI Cascaded H Bridge
DCMLI
The extension of a bridge inverter circuit to multiple voltage levels with diodes used to constrain the maximum voltage across the power switches to safe operating levels was first proposed independently by Baker
The general class of these multilevel inverters are referred to as diode-clamped or multipoint-clamped inverters
Schematic of 5 level dcmli for a phase
Advantages of DCMLI
When the Level of Inverter Increases the Harmonic content Decreases
Efficiency is high because of Inverters are Switching at Fundamental Switching Frequency
Control scheme is simple
Disadvantages
Excessive Clamping diodes required when the level is high
Difficult to control the Real Power flow of the Individual Converter In MLI
FCMLI
The capacitor-clamped multilevel converter is an alternative topology where the clamping diodes are removed and floating capacitors are used instead to clamp the node voltages in the series connected power switches.
The single flying capacitor converter was first proposed by Simon and Bronner whereas Present interest in the circuit as a multilevel converter stems from the work of Meynard and Foch who applied the basic switched capacitor bridge principle to enable voltage clamping in multiple level power converters
Schematic of 5 level FCMLI for a phase
Advantages
Capacitor provides Capabilities during Power Outages
Inverter provides Switching combination Redundancy for balancing Different voltage levels
Real and Reactive power flow can be controlled
Disadvantages
Excess Capacitor and Expensive Control Complicate Switching Frequency and Switching
losses high for Real power Transmission
Cascaded H-Bridge
The 5 Level circuit features two conventional full-bridges serially connected together with their power rails connected to separate isolated dc voltage supplies.
Number of DC sources required can be calculated as S=3(m-1)/2
Main Features
The H-bridge inverter eliminates the excessively large number of Bulky transformers required by
conventional inverters Clamping diodes required by multilevel
diode-clamped inverters Flying capacitors required by multilevel
flying-capacitor inverter.
Schematic of 5 level H-Bridge for a phase
Switching Pattern
1Hv
2Hv
21S
11S
41S
31S
22S42S
32S12S
E
E
A
H1
H2 N
3 Phase 5 Level Topology
Advantages
Less Components compared with FCMLI and DCMLI
Optimized Circuit layout and Extra Clamping
Disadvantages
Need of Separate DC Sources
Topology Comparison
Modulation Strategies
SPWM Modulation
Switching Pulses are produced by comparing the Reference wave and the Carrier wave
Reference wave Sine Wave Carrier Wave Triangular wave or
Hybrid carrier signal
Project work
Simulation
Hardware Module
Matlab Simulation
Design Analysis
Design
Power Circuit Design Switching sequence Design
Power circuit Design Per Phase
Switching Sequence Design Per Phase
Analysis
Factors considered during Analysis Modulation Technique Analysis Operation of Inverter in R , RL and
Induction Motor Loads
Parameters Chosen for Simulation• DC source Voltage 220 V
• Modulation Index 1 to 0.6
• Carrier Frequency 2000 Hz
• Rated Output Frequency 50 Hz
Factors Considered during Analysis THD DF Vrms
Vpeak
Form Factor Crest Factor
Modulation Technique Analysis
HYBRID 1
HYBRID 2
HYBRID 3
Operation of Inverter in R , RL and Induction Motor Loads
To analyze the operation of Inverter under different conditions the Inverter circuit designed in Matlab is analyzed with different loads 1) R Load 2) RL Load 3) Induction Motor load
OUTPUT VOLTAGE and FFT Analysis
HYBRID 1
HYBRID 2
HYBRID 3
HYBRID 4
HYBRID 5
HYBRID 6
HYBRID 7
HYBRID 8
SIMULATION RESULTS FOR RL LOAD
THD
Vpeak and Vrms
Distortion Factor and Crest Factor
SIMULATION RESULTS FOR INDUCTION MOTOR LOAD
Hardware Module
FPGA Module H Bridge (PC01 Module) DC Sources
FPGA Module
FPGA Module is used for Generating switching pulses for triggering the IGBT’s
FPGA Module is programmed by using xilinx IDE or Libero IDE
FPGA Module consists of 100,000-gate Xilinx Spartan-3E XC3S100E FPGA in a 144-Thin Quad Flat Pack package (XC3S100E-TQ144)
FPGA Module Block Diagram
H Bridge Module
H Bridge module consists of MOSFET’s , Power diodes, di/dt protection devices ,dv/dt protection devices.. etc
We are using 6 H bridge module for a 3 ph ,5 level inverter
(S=3(M-1)/2)
S-No of Sources; M-No of Levels.
MOSFET Specification
We are using 8A, 500V, 0.850 Ohm, N-Channel Power MOSFET Features 8A, 500V Rds(ON)= 0.850Ω Single Pulse Avalanche Energy Rated SOA is Power Dissipation Limited Nanosecond Switching Speeds Linear Transfer Characteristics High Input Impedance
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