Passive lossless snubber for CCM PFC based on magnetic coupling

Boost converter is the most popular topology in power factor corrector (PFC), which contains a switch and a diode. However the reverse recovery characteristic of silicon material diode enlarges the turning-on power losses of switch. In this paper, a novel passive lossless snubber based on magnetic coupling is proposed for continuous conduction mode (CCM) PFC, which is consisted of a winding coupled with boost inductor, one snubber inductor, one snubber capacitor and three additional diodes. Furthermore, the snubber inductor is aimed at limiting the peak reverse recovery current of diode, breaking down the clamping relationship of switch and minimizing the switch turning-on power losses greatly. The energy stored in snubber is transferred to the load by energy exchange. The coupling wingding can help the snubber inductor realizing energy reset more easily and the ranges of soft switching are expanded. Besides, the introduction of the snubber does not introduce the excess voltage stress to the switch, and the performance and efficiency of PFC are significantly improved.