Analysis and design of a zero-voltage-transition PWM flyback converter with an auxiliary resonant circuit

A novel zero-voltage-transition pulse-width-modulated (ZVT-PWM) flyback dc/dc converter with an auxiliary resonant circuit is presented in this paper. The proposed circuit topology adopts the traditional PWM flyback converter with an auxiliary resonant circuit. In the auxiliary resonant circuit, the resonant inductance and the resonant capacitance are operated as a resonant circuit to get zero-voltage-switching (ZVS) in the main switch and to get zero-current-switching (ZCS) in the auxiliary switch. The auxiliary transformer can be reset through the resonant inductance, the resonant capacitance and the auxiliary capacitance. The principles of operation, theoretical analysis, and experimental results of the novel ZVT-PWM flyback dc/dc converter, rated at 150 W and operating at 50 kHz, are implemented to verify the performance of the proposed converter.