A Wide Conversion Ratio Bidirectional Modified SEPIC Converter With Nondissipative Current Snubber

A new wide conversion ratio bidirectional dc-dc converter based on the modified Single-ended primary-inductor converter (SEPIC) converter is presented in this article. A nondissipative current snubber is included in the proposed converter allowing the operation with zero current switching, obtaining reduced switching losses and high efficiency even using conventional MOSFETs. The converter presents intrinsic extended step-up and step-down voltage conversion ratios without extreme low or high duty-cycle and reduced voltage stress in all semiconductors. The theoretical analysis with the operation stages in the step-up and step-down modes, theoretical waveforms, and design procedure are presented and also a comparison with other bidirectional converter topologies. The experimental results are presented to verify the performance of the proposed converter with a 500-W prototype operating with V
₁
= 48 V and V
₂
= 300 V and efficiency higher than 95% in both operation modes.