High Voltage Gain Soft-Switching Bidirectional DC-DC Converter With High Extendibility Using Coupled Inductor

This article proposes a generalized scheme of new soft-switching interleaved bidirectional dc-dc converters (BDCs) that is suitable for high voltage gain and high-power applications. The proposed converter is composed of proper numbers of basic cells to achieve high voltage gain and high-power transmission, which leads to high extendibility in topology. Meanwhile, the basic cell combines coupled inductors with resonant tanks, which can control the leakage inductors' energy and make the converter achieve soft switching in a wide voltage range. In addition, the converter features current sharing, reduced current ripple, and low voltage stresses as a result of the structure of interleaving parallel at the low voltage side (LVS) and series connection at the high voltage side (HVS). The operating principle, current ripple at the LVS, soft-switching conditions, voltage stresses of devices, and comparison analysis are discussed in detail. Furthermore, the parameter design of the proposed converter is presented. Finally, a 1-kW prototype with 25-80-V LVS and 400-V HVS is established to verify the performance of the converter, and the results show that its maximum efficiency reaches 97.3% in the boost mode and 97.1% in the buck mode.