Improved Control Strategy for Zero-Crossing Distortion Elimination in Totem-Pole PFC Converter with Coupled Inductor

Coupled inductors can effectively optimize the THD, loss, current ripple, and power density of multiphase interleaved totem-pole PFC converters. However, a coupled inductor will also worsen the zero-crossing distortion process. This paper first introduces the working principle of the interleaved totem-pole PFC converter with a coupled inductor based on a detailed analysis of modes, and then analyzes the influence on the zero-crossing process caused by the coupled inductor. To eliminate the zero-crossing distortion caused by the coupled inductor, an improved control strategy and its digital realization method of the totem-pole PFC converter is presented through the system model. Finally, the validity and correctness of the proposed circuit and control are verified in the 7.7 kW interleaved totem-pole PFC converter.