基于耦合绕组的锂电池组主动均衡方案研究

针对锂电池组在充放电过程中出现能量不一致的问题,采用传统的Buck-Boost均衡电路和Flyback均衡电路的均衡方法,提出一种可减小电路尺寸、提高均衡速度和均衡效率的基于耦合绕组的新型主动均衡电路。通过对耦合绕组的选择性充放电,会有三种不同的工作模式来实现单体之间的能量转移,并调节PWM驱动信号占空比来提高均衡器的工作效率。在均衡控制策略方面,根据锂电池开路电压(OCV)与荷电状态(SOC)之间的一一对应关系,提出了基于电压和SOC双变量的均衡控制策略,主要是通过电压快速均衡和修正均衡以及SOC均衡阶段同时实现电压均衡和SOC均衡,更加合理地保证电池组动态性能一致。实验结果表明,该方案可以减少电池组的均衡时间,并且降低了能量损耗,提高了均衡效率,使电池组的整体性能达到最优状态。

Research on active balancing scheme of lithium battery pack based on coupled winding

Aiming at the problem of energy inconsistency in the charging and discharging process of lithium battery packs,the traditional Buck-Boost equalization circuit and Flyback equalization circuit are used to balance the method.An active equalization circuit based on coupled windings,which can reduce circuit size,improve equalization speed and equalization efficiency,is proposed.By selectively charging and discharging the coupled windings,three different working modes realized energy transfer between the cells,and adjusted the duty cycle of the PWM drive signal to improve the working efficiency of the equalizer.In terms of the balance control strategy,according to the one-to-one correspondence between the open circuit voltage(OCV)of the lithium battery and the state of charge(SOC),a balance control strategy based on voltage and SOC dual variables was proposed,mainly through the rapid voltage balance and correction.The equalization and SOC equalization phases achieved both voltage equalization and SOC equalization,which ensures consistent dynamic performance of the battery pack.Experimental results show that the solution can reduce the equalization time of the battery pack,reduce energy loss,improve the equalization efficiency,and make the overall performance of the battery pack reach the optimal state.