Two-Degree-of-Freedom Control over Totem-pole Power Factor Corrector

Totem pole PFC (TP-PFC) generally adopts one-degree-of-freedom output voltage control. When the load changes, the dynamic characteristics of output voltage are poor, and there is obvious overshoot during the start-up. Based on the derivation of the double closed-loop control structure of TP-PFC, this paper introduces the load current feedforward control in conjunction with output voltage feedback compensation control to form two two-degree-of-freedom (2DOF) control structures. On the one hand, the simulation results show that the load current feedforward 2DOF control can effectively suppress the output voltage fluctuation caused by load change, but the overshoot is still obvious during start-up. On the other hand, the output voltage feedback compensation 2DOF control can realize the start without output voltage overshoot, but the ability to suppress load change is poor. The 2DOF control combining load current feedforward control and output voltage feedback compensation control can obtain satisfactory output voltage control effect, that is, there is no overshoot during start-up and no fluctuation when the load changes.