High-efficiency Oriented Control Method of Bidirectional CLLC Resonant DC/DC Converter for Energy Storage System

In the energy storage system, a DC/DC converter is usually deployed to ensure the wide range of voltage gain, to guarantee the life-span of battery, as well as to improve the efficiency, which puts a challenge on the seamless switch of charging modes. Therefore, a high-efficiency oriented control method is proposed for bidirectional resonant DC/DC converter based on the features of energy storage system. In the charging mode, the constant current (CC) and constant voltage (CV) schemes are combined together to properly adapt the changing equivalent inner resistance of battery. In the discharging mode, the output DC voltage of converter remains unchanged by regulating switching frequency to avoid the disturbance on the DC bus. The simulation using xx platform/software has been developed to verify the feasibility and superiority of the proposed method.