Family of Soft-Switching Single-Switch PWM Converters With Lossless Passive Snubber

To increase the power conversion density, decrease switching losses and electromagnetic interference (EMI), and provide safe operating area for a switch, applying snubber circuits which provide soft-switching conditions is inevitable. Among different types of snubber circuits, passive snubbers, due to their simplicity and robustness, are preferred. These snubber circuits can obtain soft-switching conditions without any additional switch. Thus, gate drive and control circuits remain simple. In this paper, a simple lossless passive snubber circuit which can be applied on isolated and nonisolated converters is introduced. The proposed snubber circuit provides zero-current-switching and zero-voltage-switching conditions at turn-on and turnoff instants, respectively. The proposed snubber is applied on a boost converter and analyzed. Also, in order to prove the effectiveness of the proposed snubber circuit from the converter efficiency and EMI viewpoints, a 200-W prototype boost converter is implemented, and experimental results are presented. Also, the simulation results of a soft-switched flyback converter with the proposed snubber cell are presented.