How to Use Universal Bridge in MATLAB Simulink

We will explore how to use the Universal Bridge block in MATLAB Simulink. This component, available in the Specialized Power Systems of Simscape Electrical, is essential for modeling power electronic converters like rectifiers and inverters.

Locating the Universal Bridge Block

To start using the Universal Bridge block in Simulink:

1. Open the Simulink Browser.

2. Navigate to:Simscape → Electrical → Specialized Power Systems → Power Electronics → Universal Bridge.

3. Drag and drop the block into your working environment.

The Universal Bridge is useful in modeling both AC to DC (rectifiers) and DC to AC (inverters) applications. It is suitable for single-phase and three-phase systems and supports various power electronic switching devices.

Understanding Bridge Arms Configuration

Inside the Universal Bridge block, you can configure the number of bridge arms:

• 1 arm – for single-switch applications like half-wave converters.

• 2 arms – typically for single-phase full converters.

• 3 arms – for three-phase applications.

This flexibility allows the Universal Bridge to be used in various topologies, depending on your design requirements.

Choosing Power Electronic Devices

You can select from several types of switching devices:

• Diode

• Thyristor

• GTO (Gate Turn-Off Thyristor)

• MOSFET

• IGBT

These can be configured for:

• Uncontrolled rectifiers (e.g., with diodes)

• Controlled rectifiers and inverters (e.g., with IGBTs, MOSFETs)

Additionally, average models and switching-function models can be selected for voltage source converters.

Three-Phase Diode Rectifier Example

Setup:

• Use a three-phase programmable voltage source.

• Connect it to the Universal Bridge configured with 3 bridge arms and diodes.

• Connect an R-load and measure current and voltage using measurement blocks and scopes.

Observations:

• Input voltage: sinusoidal

• Output current: non-sinusoidal due to diode switching

• Voltage output range: ~125V to 135V

• For more accurate sinusoidal waveforms, adjust the solver’s maximum step size to 1e-5.

Single-Phase Diode Rectifier Configuration

To configure the same Universal Bridge for a single-phase setup:

• Change bridge arms to 2.

• Use a single-phase AC source and an R-load.

• Connect appropriate current and voltage measurement blocks.

Results:

• Input: AC

• Output: Rectified DC

• Same Universal Bridge can be adapted with minimal changes.

Single-Phase Inverter Using IGBT

To operate the Universal Bridge as a single-phase inverter:

• Set bridge arms to 2.

• Select IGBT/diode as switching devices.

• Use a DC voltage source as input.

• Apply gating signals using a 2-level PWM generator.

• Output is connected to a resistive load.

Observations:

• Input: DC

• Output: Square wave AC (inverter behavior)

• Measure both input/output voltage and current using scopes.

Conclusion

The Universal Bridge block in MATLAB Simulink is a powerful tool for modeling:

• Rectifiers (AC to DC)

• Inverters (DC to AC)

• Both single-phase and three-phase power conversion

• Configurable with various devices: Diodes, Thyristors, IGBTs, MOSFETs

This block provides an excellent starting point for simulating real-world power electronics systems. Adjust its parameters based on your application and validate your design using simulation tools like scopes and measurement blocks.