In three-phase PFC converter,there exist severe switch anti-parallel diode reverse recovery problems.The effective measures of Compound Active-clamping and Minimum Voltage Active-clamping techniques in single phase PFC are extended to three-phase PFC.A family of Active-clamping ZVS soft switching PFC converter is got. They can effectively suppress the diode reverse recovery, and realize ZVS for all the switches. In order to reduce the number of the auxiliary switches, A ZVS space vector modulation (ZVS-SVM)is proposed. It uses only one auxiliary switch and can realize ZVS for all the switches. The switching frequency of the main switch and the auxiliary switch is fixed, thus the input current waveform is good.The theory has been illustrated by the compound active-clamp (CAC) three phase PFC. One DSP controlled 4kW PFC converter prototype with CAC is implemented.
