基于反激变换器的双目标直接均衡方法

The Dual-Objective Direct Balancing Method Based on Flyback Converter

新能源汽车串联电池组各单体间不可避免的不一致性将会降低电池组的能量利用率及循环寿命,甚至危及新能源汽车使用安全。为改善串联电池组的不一致性,该文创新性地提出一种基于反激变换器的均衡拓扑,利用结构简单可靠的反激变换器实现均衡能量在整组电池和任意单体间转移,所提出的拓扑减少了储能元件的数量,降低了均衡系统的体积,而且能量传递的一次侧仅需一组控制信号,降低了控制难度;在此拓扑基础上,提出一种双目标直接均衡控制策略,将充电过程和放电过程的均衡合二为一,同时实现充/放电过程最高端电压的降低和最低端电压的升高。仿真及实验结果表明,该文所提新型均衡方法具有良好的动静态均衡效果,能够显著地改善串联电池组的一致性。

The inevitable inconsistency among the cells of series battery pack of new energy vehicles will reduce the energy efficiency and cycle life of the battery pack,and even endanger the safety of the battery system.In order to improve the consistency of series battery pack,this paper innovatively proposes a balancing topology based on flyback converter,which uses a simple and reliable structure to realize the energy transfer between the whole battery and any single cell.The proposed balancing topology reduces the number of components and the volume of the balancing system,and only requires one set of signals on the primary side of the energy transfer,which reduces the control difficulty.Based on this topology,a dual-objective direct balancing control strategy is proposed,which combines the balancing of the charging process and the discharging process into one.Meanwhile,the reduction of the highest terminal voltage and the increase of the lowest terminal voltage in the charging/discharging process are realized.The simulation and experimental results show that the novel balancing method proposed in this paper has a good dynamic and static balancing effect,and can significantly improve the consistency of the series battery pack.