基于改进Buck-Boost的分层均衡电路研究

Research on Hierarchical Equalization Circuit Based on Improved Buck-Boost

针对传统Buck-Boost均衡电路在电池数量增多时,会造成均衡时间长,效率低等问题,提出了一种改进Buck-Boost的分层均衡电路拓扑结构。该均衡电路在组内电池与电池或电池组与电池组之间采用双向Buck-Boost均衡器,利用电感储存和传递能量,在组间两电池包之间采用外加外部电源的反激式变压器进行不同程度的充电来达到均衡。以电池的荷电状态(SOC)作为均衡变量,在MATLAB/Simulink中搭建了8节串联锂电池组仿真模型,4节串联电池为一个电池包,两个电池包之间采用组间均衡,设置8节电池直接均衡为对照组。结果表明:在静置状态下,分层均衡所需时间比直接均衡快9.18%,且均衡后分层均衡的容量比直接均衡高1.1%。在外加电源下,能较快将电池组充满电,验证了所提均衡电路的有效性。

Aiming at the problems that the traditional Buck-Boost equalization circuit will cause long equalization time and low efficiency when the number of batteries increases, this paper proposes an improved Buck-Boost layered equalization circuit topology. The equalizing circuit adopts a bidirectional Buck-Boost equalizer between the batteries in the group and the battery or between the battery group and the battery group, uses the inductance to store and transmit energy, and uses a flyback transformer with an external power supply between the two battery packs between the groups. Different levels of charging to achieve the equalization process. In this paper, the state of charge(SOC) of the battery is used as the equilibrium variable, and a simulation model of an 8-series lithium battery pack is built in MATLAB/Simulink. Set 8 batteries to be directly equalized as the control group. The results show that: in the static state, the time required for layered equilibrium is 9.18% faster than that of direct equilibrium, and the capacity of layered equilibrium after equilibrium is 1.1% higher than that of direct equilibrium. Under the external power supply, the battery pack can be fully charged quickly, which verifies the effectiveness of the proposed equalization circuit.