Cubic Synchronous Bidirectional DC–DC Battery Charger Converter With Common-Ground and High Voltage Gain Ratio Features

This paper presents a novel bidirectional dc-dc converter with a cubic voltage gain ratio, designed to address the limitations of existing converter topologies and enhance performance in dc microgrid applications. The proposed converter features a common ground connection, wide and high voltage gain range, and improved semiconductor utilization. Key contributions of this work include achieving the highest voltage gain ratio compared to existing bidirectional converters, reducing total current stress on semiconductor devices, and implementing zero voltage switching (ZVS) to minimize switching losses. A prototype of the converter was constructed and tested with a 40 V Nickel-cadmium battery with the dc source voltage of 400 V. The experimental results closely aligning with theoretical predictions, confirming the converter's practical viability. The converter exhibits the capability for battery charging/discharging and demonstrates a peak efficiency of 97.6% and 96.33% in the step-down and the step-up mode of operation, respectively.