A simple ZVT auxiliary circuit for full-bridge based bridgeless single-phase PFC with hybrid PWM modulation scheme

Abstract

This paper proposes a zero-voltage-transition (ZVT) technique for the full-bridge based bridgeless single-phase PFC. An auxiliary circuit consists of a small auxiliary inductor and two active switches is placed in parallel with the main filter inductor. The proposed ZVT technique has several advantages over the existing ZVT schemes including low ripple of the filter inductor current, natural zero-current-switching (ZCS) for the auxiliary switches, relatively less additional components and allowing unipolar or hybrid PWM modulation of the full-bridge converter. The effectiveness of the proposed scheme has been validated through hardware experiment. It shows that the proposed ZVT scheme can save approximately 40% of the power loss compared with the regular hard-switching operation.