Efficient Single-Switch Boost-Dual-Input Flyback PFC Converter With Reduced Switching Loss

Abstract

This paper presents an efficient single-switch boost-dual-input flyback power factor correction (PFC) converter. To achieve a high power factor, a boost PFC cell operating in discontinuous conduction mode is presented. A dual-input flyback dc–dc module, which consists of parallel primary windings and serial secondary windings, operating in critical conduction mode is introduced for galvanic isolation and valley-switching operation. In addition, the proposed converter features high efficiency because the input power is equally divided, and some power is directly transferred to the load by the dual-input flyback dc–dc module. The remaining power is stored in dc-bus capacitors, and it is closely related to the holdup time. Moreover, the currents in the leakage inductors are absorbed by the dc-bus capacitors through a snubber diode, and they are reprocessed by the dual-input flyback dc–dc module. Consequently, the peak voltage in the MOSFET drain is clamped, and the total power conversion efficiency is improved. To verify the performance of the proposed converter, the operating principles, steady-state analysis, and experimental results from a 48 V, 100 W prototype are presented.