PWM Rectifier Simulation Model

A PWM rectifier is a common power electronic converter widely used for energy conversion between AC grids and DC loads. Its simulation model holds significant importance for research and design of power electronic systems.

The core of PWM rectifier simulation lies in modeling its switching behavior and control system. First, the main circuit topology must be established, typically including bridge rectifier structures (such as three-phase or single-phase full bridge) along with supporting filter inductors and capacitors. Second, PWM modulation strategies are crucial, with common techniques including SPWM (Sinusoidal Pulse Width Modulation) and SVPWM (Space Vector Pulse Width Modulation), which determine the switching sequences of power devices. In code implementation, these modulations require precise timing calculations and duty cycle generation algorithms.

The control system simulation is equally important, typically employing a dual-loop control strategy: the outer loop regulates DC-side voltage to maintain output stability, while the inner loop controls input current to synchronize with grid voltage, achieving unity power factor operation. During simulation, special attention must be paid to sampling time, switching frequency, and discretization of control algorithms to ensure model accuracy. The control algorithm implementation often involves PID controllers and coordinate transformation modules (abc/dq transformation) for effective current regulation.

Simulation models can be developed using tools like MATLAB/Simulink or PLECS, where parameter adjustments allow observation of key performance indicators including dynamic response, harmonic characteristics, and efficiency. These models provide valuable references for optimizing control algorithms, analyzing system stability, and performing fault diagnosis. The simulation typically involves power electronics libraries and custom function blocks for switching logic and control system implementation.