基于分层架构的退役电池可重构均衡控制研究

Reconfigurable balanced control of retired batteries based on hierarchical architecture

利用退役电池构建储能系统,充分利用其剩余价值,是解决大量退役电池再利用的重要途径。然而,经过多次充放电影响,退役电池不一致性问题较新电池更为突出。在此背景下,首先,针对退役电池储能系统提出了分层式可重构均衡拓扑。其次,基于该拓扑提出了分层式均衡控制策略。考虑组内部和组间两个层次的均衡控制,组内以SOC和端电压为均衡变量,通过重构实现电池单体状态均衡,组间以SOC为均衡变量,通过重构保证全电池簇均衡。同时考虑多种运行工况:静置过程中通过自均衡提高电池组的均衡效率和可用容量,放电过程中通过拓扑结构变换维持输出电压稳定,充电过程中考虑能量损耗和充电速度合理优化充电电流,缩短充电时间,减少温升,延长电池使用寿命。最后,在Matlab中验证了所提拓扑与均衡策略在不同工况下的有效性。

Using retired batteries to construct a grid energy storage system can make full use of their residual value.This is an important way to solve the problem of reusing a large number of retired batteries.However,because they have been charged and discharged many time,there is an inconsistency problem that is more prominent than that with new batteries.First,a reconfigurable hierarchical balancing topology for retired batteries is proposed.Secondly,a hierarchical balanced control strategy is proposed based on this topology.Two levels of equalization control,i.e.intra-and inter-group are considered.SOC and terminal voltage are used as balancing variables within the group to achieve single cell state equalization through reconfiguration.SOC is used as a balancing variable between groups to ensure whole cell cluster equalization through reconfiguration.It simultaneously considers different operating conditions:balancing efficiency and usable capacity of battery packs is increased by self-equalization in static balancing.The output voltage stability is maintained by topology transformation in the discharging process.Charging current is reasonably optimized considering energy loss and charging speed in the charging process to shorten the charging time,reduce the temperature rise and improve service life.Finally,the effectiveness of the proposed topology and strategy in different operating conditions is verified in Matlab.