A novel single-phase soft-switching unipolar PWM rectifier

This paper proposed a novel single-phase soft-switching unipolar PWM rectifier (SSUPR) using a simple auxiliary resonant unit. All main switches of high-frequency arm operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-off. All main switches of low-frequency arm operate at 60 Hz to greatly reduce switching losses. Moreover, a soft-switching unipolar PWM strategy is used for the proposed soft-switching rectifier. This strategy results in a better input current waveform than for the bipolar PWM strategy. Furthermore, the proposed rectifier achieves a near unity power factor, sinusoidal input current and a bidirectional power flow capability. Some simulation results of the proposed SSUPR, rated 400 W and operated at 40 kHz, are presented for verification.