Optimized Bidirectional DC-DC Converter Adapted to High Voltage Gain and Wide ZVS Range

As a key component connecting dc microgrid and energy storage system, dual active bridge (DAB) converter has some inherent problems under high gain conditions. To solve the problems, this article proposes a half-bridge cascaded DAB converter with partial switch sharing. The converter combines the advantages of high voltage gain, wide soft switching range and less reactive backflow loss, under a hybrid modulation strategy based on pulsewidth modulation control and phase-shift control. In this article, the output power, soft switching characteristic and reactive backflow loss are analyzed in detail. By using the Karush–Kuhn–Tucker function method to achieve multiobjective optimization, the system can achieve the zero voltage switch (ZVS) turn- on and reduce the reactive backflow loss. Moreover, the coupled relationships among variables are clarified clearly, and the system can achieve high voltage gain at low turns ratio. A 500 W, 100 kHz experimental prototype is built to verify the correctness of the theoretical analysis.