串联电池组双向全桥SOC均衡控制系统设计

Bidirectional full-bridge converter based SOC equalization system design for series-connected battery string

针对电池制造工艺和使用环境不同所引起的单体间电量不均衡问题,结合双向开关电源理论提出了一种集中式能量转移型单体-整组双向电池均衡方案,根据电池组内单体剩余电量(state of charge,SOC)在电池组内部进行电量双向转移,采用反馈电路保证均衡电流恒定。通过实验获得电池单体开路电压的滞回特性曲线,并结合充电和放电状态下SOC与开路电压对应关系估计各电池单体SOC,以SOC一致作为均衡目标。实验结果表明,所设计的均衡器均衡电流达到3A,可以满足电池系统均衡需求。

The operation environment and manufacturing process cause the problem of charge imbalance for battery pack. In order to solve the problem, a bidirectional equalization strategy using centralized structureis was proposed. The bidirectional energy transfer was implemented by a bidirectional full-bridge converter. Close loop control makes equalization current constant. The cell SOCs were estimated by using the Open Circuit Voltage（OCV） charging and discharging curves considering the hysteresis effect. Experi-ments were taken to evaluate the performance. The equalization current is 3A, which satisfies the require-ment of equalization for battery pack.