Closed-Loop Full-Bridge SMPS with Double PI Control

Interactive Simulink model of a closed-loop full-bridge SMPS with cascaded voltage-current PI control and adjustable output voltage/load.

This Simulink model demonstrates a closed-loop full-bridge Switch Mode Power Supply (SMPS) designed for educational purposes. The converter operates from a 240 V, 50 Hz AC input and provides an adjustable 6 V to 24 V DC output. The control system employs a cascaded (double-loop) PI controller, consisting of an outer voltage control loop and an inner current control loop to achieve stable output voltage regulation under varying load conditions.

The model includes interactive dashboard controls that allow the user to change the output voltage reference and vary the load resistance while the simulation is running. Real-time voltage and current indicators display the converter response immediately, making it easy to observe the transient and steady-state behavior of the closed-loop control system. To prevent excessive loading during demonstrations, the load resistance should be adjusted so that the output power remains below 100 W.

This model is intended for students, educators, and engineers who wish to study the operation of a full-bridge isolated DC power supply and understand the interaction between voltage and current control loops. Simply run the simulation and rotate the Output Voltage and Load Resistance knobs to observe the dynamic response of the SMPS.