A New Interleaved Coupled-Inductor Nonisolated Soft-Switching Bidirectional DC-DC Converter With High Voltage Gain Ratio

This paper presents a new interleaved coupled-inductor nonisolated bidirectional dc-dc converter that provides high voltage gain ratio (VGR), low ripple current at the low-voltage side (LVS), and soft switching. The high VGR is obtained by connecting in series the outputs of an interleaved bidirectional buck-boost converter and a dual-active half-bridge converter, using the turns ratio of a coupled inductor. Since the voltage of the high-voltage side is shared between the converters outputs, the voltage stress across the active switches decrease. The active switches turn ON under zero-voltage switching condition in both directions. Moreover, the low current ripple at the LVS is achieved due to the applied interleaved technique. By employing the phase-shift angle modulation, the output voltage is regulated. The proposed converter is analyzed in details and a 900-W experimental prototype with 48-V input voltage and 400-V output voltage under 100-kHz switching frequency is implemented to verify the theoretical results.