How to Simulate Inverter in Simulink: Step-by-Step Guide

To simulate an inverter in Simulink, create a model using power electronics blocks like IGBT or MOSFET switches, a DC voltage source, and a pulse generator for gate signals. Use the Simscape Electrical toolbox to build the inverter circuit and run the simulation to observe output AC waveforms.

Syntax

In Simulink, simulating an inverter involves connecting these main components:

• DC Voltage Source: Provides input DC power.
• Power Electronic Switches: Use IGBT or MOSFET blocks to switch current.
• Pulse Generator: Creates gate signals to control switches.
• Load: Represents the device powered by the inverter, often a resistor or motor.
• Measurement Blocks: To observe voltage and current waveforms.

The basic syntax is to connect these blocks in a Simulink model and configure parameters like switching frequency and DC voltage.

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Simulink Model Components:
- DC Voltage Source
- IGBT or MOSFET Switches
- Pulse Generator (PWM signals)
- Load (Resistive or Inductive)
- Scope for output visualization

Example

This example shows how to build a simple single-phase inverter model in Simulink using the Simscape Electrical toolbox.

It demonstrates generating PWM signals to control IGBT switches and converting DC input to AC output.

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1. Open Simulink and create a new model.
2. Add the following blocks from Simscape > Electrical > Specialized Power Systems:
   - DC Voltage Source
   - IGBT
   - Pulse Generator (set to PWM mode or use a PWM Generator block)
   - Resistive Load
   - Scope
3. Connect the DC Voltage Source to the IGBT switches arranged in an H-bridge configuration.
4. Connect the Pulse Generator outputs to the gate terminals of the IGBTs.
5. Connect the load to the output of the H-bridge.
6. Connect measurement blocks to monitor output voltage and current.
7. Set simulation parameters (e.g., stop time, solver type).
8. Run the simulation and observe the AC waveform on the Scope block.

Output

The Scope displays a sinusoidal AC voltage waveform at the inverter output, showing successful DC to AC conversion.

Common Pitfalls

When simulating inverters in Simulink, watch out for these common mistakes:

• Incorrect PWM signal timing: Overlapping gate signals can short the DC source.
• Missing freewheeling diodes: Can cause unrealistic current paths and simulation errors.
• Using ideal switches without losses: May give overly optimistic results.
• Not setting solver options properly: Use a fixed-step solver for power electronics simulations.
• Ignoring initial conditions: Can cause simulation instability or unrealistic startup behavior.

Example of a wrong and right PWM signal setup:

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Wrong PWM signals:
- Both upper and lower switches ON simultaneously causing short circuit.

Right PWM signals:
- Upper and lower switches are complementary with dead time to avoid short circuit.

Quick Reference

Component	Purpose	Notes
DC Voltage Source	Provides input power	Set voltage level as per design
IGBT/MOSFET Switches	Switch current on/off	Use complementary PWM signals with dead time
Pulse Generator	Generates gate signals	Configure frequency and duty cycle for desired output
Load	Represents output device	Can be resistive, inductive, or motor
Scope	Visualizes waveforms	Monitor voltage and current outputs

Key Takeaways

Use Simscape Electrical blocks like IGBT and DC Voltage Source to build inverter models.

Generate proper PWM signals with dead time to control switches safely.

Set solver to fixed-step for accurate power electronics simulation.

Include measurement blocks to observe inverter output waveforms.

Avoid simultaneous ON states of complementary switches to prevent short circuits.