Modeling and Simulation of PWM Rectifiers with Dual-Loop Control Implementation

Modeling, Simulation and Dual-Loop Control Implementation of PWM Rectifiers

In power electronics, PWM rectifiers are widely adopted due to their advantages such as high power factor and low harmonic pollution. By establishing accurate mathematical models, control strategies can be effectively validated in simulation environments. Common modeling approaches for PWM rectifiers include switch-function-based average models and detailed switching device models. The average model is suitable for system-level simulation and control algorithm development, while the switching model provides more accurate hardware representation for detailed performance analysis.

Dual-loop control is crucial for enhancing the dynamic performance of PWM rectifiers. The typical structure consists of an outer voltage loop and an inner current loop: Voltage Outer Loop: Maintains stable load voltage by regulating the DC-side output voltage reference. Typically implemented using PI controllers, where the controller output serves as the reference command for the inner current loop. In code implementation, this involves voltage error calculation and PI regulator computation with anti-windup protection. Current Inner Loop: Rapidly tracks current commands from the voltage loop to achieve sinusoidal grid current and unity power factor control. The current loop requires high-bandwidth design, commonly implemented using PI or proportional resonant (PR) controllers. Algorithm implementation typically involves coordinate transformation (abc/dq) and decoupling control for independent dq-axis current regulation.

During simulation validation, parameter tuning must be carefully considered, including the impact of inductance/capacitance values and switching frequency on dynamic loop response. Successful case studies demonstrate that the dual-loop structure can effectively suppress load disturbances and grid fluctuations, validating the feasibility of both the model and control strategy. Simulation code typically includes system initialization, controller parameter configuration, and real-time monitoring of key performance indicators.