电池组电压-SOC分段均衡控制方法研究

Study of Battery Pack Voltage-SOC Segmental Equalisation Control Method

针对电池组在充放电始末端电压变化快,以荷电状态(SOC)为均衡变量时电压误差大,在电压平台期以电压为均衡变量时SOC误差大的问题,提出了一种电压-SOC分段均衡控制策略。根据开路电压与SOC的关系变化曲线进行分段,在充放电始末端以电压作为均衡变量;在电压平台期以通过拉格朗日中值定理由电压推及的SOC之差作为均衡变量,同时运用电压均衡计算量少、SOC均衡效果好的优点。为验证均衡策略有效性,进行仿真验证并搭建了实验平台进行实验。实验结果表明,与单一均衡变量相比,电池组充放电完成后能同时保持电压和SOC良好的均衡效果,电压误差降低1.3%,SOC离散度降低0.2%,有效提高了电池组的一致性。

A voltage-state of charge(SOC) segmental equalisation control strategy is proposed for the problem that the voltage of the battery pack changes rapidly at the beginning and end of charging and discharging,and the voltage error is large when the SOC is used as the equalisation variable,and the SOC error is large when the voltage is used as the equalisation variable during the voltage plateau period.According to the relationship between the open circuit voltage and SOC,the voltage is used as the equalisation variable at the beginning and end of the charge/discharge period,and the difference between the SOC and the Lagrangian median voltage is used as the equalisation variable during the voltage plateau period,which has the advantages of less calculation and better SOC equalisation effection.In order to verify the effectiveness of the equalisation strategy,simulations are carried out to verify and an experimental platform is built for the experiments.The experimental results show that,compared with a single equalisation variable,the battery pack can maintain good equalisation of both voltage and SOC after charging and discharging,with a 1.3% reduction in voltage error and 0.2% reduction in SOC dispersion,effectively improving the consistency of the battery pack.