动力电池分层均衡控制研究

提出一种分层均衡电路，用于解决锂离子电池在串联成组时，由于单体电池的不一致性，产生的部分电池过充和过放的问题。分层均衡电路以单体电池荷电状态(state of charge, SOC)值作为均衡变量，将电池组分为3个小组，组内进行基于Buck变换器的均衡；在各小组之间搭建Buck-Boost电路，进行组间均衡。组内均衡与组间均衡相结合，提高了均衡效率。在MATLAB/Simulink平台搭建的仿真结果表明，相对于基于Buck变换器和基于Buck-Boost变换器的均衡电路，分层均衡电路在静置、充电和放电3种工况下，均衡时间相比基于Buck的均衡电路分别降低了21%、18%和30%,相比基于Buck-Boost的均衡电路分别降低了17%、29%和15%。电池组的均衡实验表明，该电路提高了单体电池一致性，能将电池组SOC值极差控制在0.1%以内，解决部分电池过充和过放问题，同时提高了均衡效率。

Research on hierarchical equalization control of power battery

A hierarchical equalization circuit is proposed to solve the problem of partial over charge and over discharge of lithium-ion battery, due to the inconsistency of single battery in series group. The hierarchical equalization circuit takes the state of charge (SOC) value of single battery as equalization variable, divides battery pack into three groups, and carries out equalization based on Buck converter within the group; Buck-Boost circuit was built between each group to realize bidirectional flow of electricity between groups and balance between groups. The combination of intra-group balancing and inter-group balancing improves the balancing efficiency. The simulation results built on MATLAB/Simulink platform show that compared with the equalization circuit based on Buck converter and Buck-Boost converter, the hierarchical equalization circuit can operate under static, charging and discharging conditions, compared with Buck-based equalization circuits, the equalization time is reduced by 21%, 18% and 30%, respectively, and compared with Buck-Boost equalization circuits, the equalization time is reduced by 17%, 29% and 15%, respectively. The equalization experiment of the battery pack shows that the circuit can improve the consistency of these single batteries, control the SOC value range of the battery pack within 0.1%, solve the problem of overcharge and over discharge of partial batteries, and improve the equalization efficiency.