High gain soft-switching bidirectional DC-DC converters for eco-friendly vehicles

This paper proposes a non-isolated soft-switching bidirectional DC-DC converter suitable for high step-up and step-down applications. The proposed converter can achieve ZVS turn on of all switches and ZCS turn off of some switches in both CCM boost and buck operations. An optimized switching strategy is presented to minimize switch current rating and achieve soft-switching in wider range. An intermediate switching pattern is introduced to carry out seamless mode change. Experimental results from a 5kW prototype are provided to validate the proposed concept.