A High Voltage Gain Soft-Switching Bidirectional DC-DC Converter With Wide Range Using Resonant Network

Abstract

A soft-switching bidirectional dc–dc converter (BDC) is proposed for high voltage gain and wide range applications. A resonant network composed of a coupled inductor and resonant capacitors is integrated into an interleaved buck/boost BDC to achieve high voltage gain. Meanwhile, the resonant network can control the circulating leakage inductor's energy and suppress the change of the resonant current, which allows the converter to realize soft switching at light and full load in a wide voltage range. In addition, the converter features current sharing, small 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). Moreover, the working principle of the converter is analyzed in detail, and the steady-state operating characteristics including voltage gain and soft-switching conditions are discussed. Finally, a 1 kW prototype with 25–100 V LVS and 400 V HVS is established to verify the performance of the converter, and results show that its maximum efficiency reaches 97.8% in boost mode and 97.5% in buck mode.