Comparison of bi-directional isolated full-bridge converters with combinations of active and passive snubbers

A bi-directional isolated full-bridge dc-dc converter with high conversion ratio is widely used for battery charging/discharging. Active or passive snubbers are usually adopted to supplement the operation of a dual full-bridge configuration. In the paper, a bi-directional isolated full-bridge converter with an active flyback snubber, and the one with an active flyback snubber and two passive capacitor-diode snubbers are analyzed, designed and implemented. A comprehensive comparison between the two converters, including component stress, soft-switching feature and conversion efficiency, is presented. Finally, two experimental prototypes of 1.5 kW with low-side voltage of 48V and high-side voltage of 360V have been implemented to verify the analysis and its feasibility.