PWM-quasi-sliding mode control for APFC converters

This paper presents the design and analysis of a PWM-quasi-sliding mode controller for active power factor correction (APFC) converters from a theoretical perspective. A novel design method, which contains the external ramp signal information in switching function, can be used to design a sliding mode controller with a constant switching frequency without any slope matching issues. The rigorous conclusions for reaching conditions and system stability conditions are given according to the PWM-quasi-sliding mode control theory. Three different approaches, namely conventional sliding mode control, triangular sliding mode control and PWM-quasi-sliding mode control, are compared in this paper. The simulation results show that the performance of PWM-quasi-sliding mode control agrees with the theoretical design, and this mode shows better working characteristic than conventional sliding mode control and triangular sliding mode control.