A true ZCZVT commutation cell for PWM converters

A true zero current and zero voltage transition (ZCZVT) commutation cell for DC-DC PWM converters is introduced. It provides zero current switching (ZCS) and zero voltage switching (ZVS) simultaneously, at both turn-on and turn-off of the main switches and zero voltage switching (ZVS) for the main diodes. The proposed soft-switching technique is suitable for both minority and majority carrier semiconductor devices, and can be implemented in several DC-DC PWM converters. The shunt resonant network of the ZCZVT commutation cell is placed out the power path and therefore, there are no voltage stresses on power semiconductor devices. It is activated during the main switches transitions only and is composed by fewer auxiliary devices, rated at small power. The operation of the ZCZVT commutation cell applied to a boost converter is explained and analyzed theoretical and experimentally, from a prototype operating at 40 kHz, with an input voltage rated at 155 V and 1 kW output power. The measured efficiency at full load was 97.9%.