A High Voltage Gain Wide Range Soft-switching Bidirectional DC-DC Converter

A bidirectional DC-DC converter topology with high voltage gain and wide range soft-switching is proposed. Based on the bidirectional Buck/Boost structure, the converter uses the leakage inductance of the coupling inductor to resonate in series with the resonant capacitor and achieves high voltage gain without operating the switches at extreme duty cycle. Meanwhile, the resonant cavity composed of the leakage inductance of the coupling inductor and the resonant capacitor can not only control the circulating leakage inductance energy, but also suppress the change of the resonant current, so that it can still realize soft switching under full load condition in a wide voltage range at the low voltage side. In addition, the topology adopts the structure of interleaving parallel at the low voltage side (LVS) and series connection at the high voltage side (HVS), which makes the converter have the characteristics of small phase current, small current ripple at the LVS and low voltage stress. Moreover, the working principle of the converter is analyzed in detail, and the steady-state operating characteristics of the converter, such as voltage gain and soft switching conditions, are discussed. Finally, a 2kW prototype with 40~150V LVS and 400V HVS is established to verify the performance of the converter. ©2023 Chin.Soc.for Elec.Eng.