A novel constant-frequency hysteresis current control of PFC converters

A novel adaptive-hysteresis (nearly) constant-frequency current control technique for single-phase switchmode rectifiers operating in continuous conduction mode is presented. It is based on cycle-by-cycle hysteresis calculator, which generates the hysteresis window that will keep the switching frequency in a very narrow band centered around programmed average value. The accuracy remains excellent, and the ripple content allows the use of a smaller input filter than usual, due to a lack of the single frequency peak. Experimental results on a 700W converter are presented and compared to the convention control.