A novel single-phase soft-switching unipolar PWM inverter

摘要

A novel single-phase soft-switching unipolar PWM inverter (SSUPI) using a simple auxiliary resonant unit is proposed. 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. As a result, commutations of the main power devices occur with low losses. Consequently, higher efficiency is achieved. Moreover, a unipolar PWM scheme is used to reduce the output voltage harmonics. Some experimental results of the proposed SSUPI, rated 500 W and operated at 40 kHz, are presented for demonstration.