Abstract: To address the issues of complex dynamic processes and insufficient robustness of the quadratic Boost converter under high-gain operating conditions, a composite control strategy combining an outer-loop PI controller with an inner-loop model predictive controller is proposed. Under the same main-circuit model and parameter settings, three control schemes, namely single-loop PI, dual-loop PI, and PI+MPC, are simulated and compared under different disturbance conditions. The results show that all three methods can achieve basic voltage regulation under no-disturbance conditions. Under input-voltage sag disturbance, the PI+MPC control can still recover to the reference value, whereas the minimum output voltage of the single-loop PI scheme drops to merely about 1.88 V and fails to re-establish stable output after recovery. Under strong-disturbance conditions, compared with dual-loop PI control, the proposed PI+MPC control shortens the recovery time by approximately 12.7%, reduces the voltage sag magnitude by 54.3%, and decreases the peak-to-peak value of local steady-state fluctuations by 11.3%. The results verify the effectiveness of the proposed PI+MPC composite control strategy in improving the dynamic response, disturbance rejection capability, and overall regulation performance of the quadratic Boost converter.

Key words: quadratic boost converter, PI+MPC control, performance comparison