Design of a Bidirectional DC/AC Converter with Battery Charging/Discharging/Standing Balance Control

Battery cells connected in series have been widely used in high-voltage and high-power applications. In this paper, a single-phase battery energy storage system with battery balance charging, battery balance discharging, and power factor correction capabilities was developed. A prototype suitable for a single-phase 110V power supply was designed and implemented for verification. To verify its performance, three 48V/7 Ah battery modules were used as normal batteries, and a 48V/5Ah battery module was used as a retired battery. The experimental results showed that the battery energy storage system has excellent battery balancing capability. Compared with that of the conventional system without balanced control, the balancing performance of the proposed system is increased by about 15.25% and 26.92%, respectively, when the system was operated in the converter and rectifier modes. In addition, the proposed system also had battery fault tolerance, and was compatible with recycled batteries and an independent power supply.