Zero-voltage-transition converters with a soft-switching auxiliary circuit and reduced current stresses

A new family of single switch, pulsewidth modulated (PWM) converters that use an auxiliary switch to allow the main converter switch to operate with zero-voltage switching (ZVS) is proposed in this paper. The main feature of the proposed family of converters is that the auxiliary switch can operate with a zero-current switching (ZCS) turn-on and turn-off without increasing peak stresses on the main switch. This allows the main switch to operate with ZVS with auxiliary switch switching losses and main switch conduction losses that are lower than other previously proposed converters of this type. In this paper, the fundamental principles behind the proposed family of converters are explained and new converters of this family are derived and presented. The operation of an example boost converter is discussed, then analyzed in detail. The feasibility of this converter is confirmed by experimental results obtained from a 500 W, 100 kHz laboratory prototype.