Flyback lossless passive snubber

To increase power conversion density, it is inevitably necessary to increase switching frequency. However, doing so has detrimental effects, including reduced efficiency and increased EMI under hard-switching operation. To prevent the side effects of high switching frequencies, soft switching methods present advantages. In this paper, a lossless passive snubber circuit that operates based on the flyback converter is introduced. The proposed snubber circuit is not only able to produce ZVS and ZCS conditions for the converter switch, but also to produce soft switching conditions for the other semiconductor elements. The snubber circuit is applied to a flyback converter and the experimental results are presented to justify the theoretical analysis. The outcomes show that the proposed converter improved efficiency by over 3% compared with the hard switching flyback converter.