ZVS-PWM flyback converter with a simple auxiliary circuit

A novel zero-voltage-switching (ZVS) pulse-width-modulated flyback dc/dc converter with a simple auxiliary circuit is proposed. The auxiliary circuit is configured in the presented ZVS-PWM flyback converter to perform soft-switching in the semiconductor devices and soft commutation of the main switches without additional current stress. Eight transition states for describing the behaviour of the ZVS-PWM flyback converter in one switching period are described. A prototype rated at 150W, operating 80kHz has been implemented in laboratory. Analysis, design, and the control circuitry are also presented.