A soft-switching strategy for three-phase boost power factor correction rectifiers

This paper proposes a novel resonant active-clamped soft-switching method for a three-phase six-switch boost power factor correction rectifier, where all the main switches can undergo zero voltage switching (ZVS). It is realized by an additional efficient auxiliary circuit. The additional soft-switching circuit consists of three active switches and one resonant inductor. The ZVS for all the six switches can be ensured by proper selection of resonant parameters. Although the soft-switching auxiliary circuit consumes 3 active switches, the analysis in this manuscript shows that zero-voltage switching can also be achieved in these auxiliary switches, without any extra losses for the auxiliary circuit. A 2.2-kW three-phase boost PFC prototype with the additional auxiliary circuit for soft-switching is developed and tested to verify the occurrence of ZVS at the six switches with the proposed circuit. The experimental results show a reduction in total loss by 40% and hence, an increase in conversion efficiency from 98.2% to 99% at 2.2kW load power with maintaining unity power factor.