Improved three-phase single-stage isolated PFC converter with voltage-clamping in primary side

An improved three-phase single-stage isolated power factor correction (PFC) converter topology is studied in this paper. The converter is based on full-bridge structure and operates in constant-frequency discontinuous conduction mode (DCM). Through the analysis on the working principle and mechanism of voltage spike of the original topology, a voltage-clamping circuit is proposed and added in primary side of the converter which can suppress the voltage spike and improve the soft-switching of the leading-leg switches. The analysis of input current and realization conditions for DCM are given in details. Finally the validity of theoretical analysis is verified through simulation and experiment.