High Efficiency High Power Density Bidirectional DC-DC Converter for Photovoltaic Energy Storage System Utilization

In this paper, a high efficiency high power density bidirectional dc-dc converter with wide dc gain range face to photovoltaic energy storage system (PESS) based on the 24V battery module is proposed. The dc-dc converter uses two-stage topology, which meets the demand of wide gain range in PESS. The surface mounted devices (SMD) for synchronous rectification were used here to improve power density. The optimized design method of the converter is proposed. A 4kW prototype was built and the experimental results are given in the paper. The highest efficiency is up to 97.5% in charging mode and 96% in discharging mode. The power density of the converter can achieve 650W/L.