Soft-Switching Bidirectional Buck/Boost Converter With a Lossless Passive Snubber

This article introduces a new lossless passive snubber for the bidirectional buck/boost converter. The proposed snubber comprises a low number of passive components which jointly contribute to achieve soft switching condition at both the buck and boost operations of the converter. Without using the auxiliary switch, soft switching condition is ensured over a wide load range with a relatively low circulating current. Also, there is no need for any complex control method to diminish circulating current at light loads. Consequently, by using a simple auxiliary circuit and the conventional control methods, excellent efficiency is acquired over a wide load range. The proposed topology is analyzed in detail and to confirm the theoretical analysis, the experimental results of a 500 W–100 kHz prototype for both the boost and buck modes in full-load and 20% of full-load are presented.