A novel soft-switched bidirectional single-phase PWM AC chopper with a lossless active snubber circuit

A novel soft-switched AC boost converter with an active snubber is proposed and analyzed. It has a bidirectional active power transfer capability, from low voltage to high voltage or reverse. The energy of switch capacitors is retrieved and delivered to the high voltage side. The snubber provides zero voltage switching (ZVS) for all the main switches in all input voltage and current polarities. The auxiliary switches also have zero current switching (ZCS) turn on and zero voltage switching (ZVS) turn off. The performance of the proposed converter was evaluated on a 150 kHz, 500W prototype. Experimental results show that the proposed snubber improves the efficiency by 3% at half the nominal load.