一种单电感双向电池均衡电路

Single-inductor bidirectional battery equalizer

针对传统集中式电池均衡电路体积大、不易扩展、均衡精确度低;而分布式均衡电路存在元件多、成本高的问题,提出了一种单电感双向电池均衡电路,该均衡电路采用Buck-Boost变换器与开关矩阵相结合的方式实现对整个电池组的均衡,通过对电感的时分复用实现对每一个电池独立均衡控制。均衡电路中电感电流工作于断续模式,消除了各电池之间的交叉影响。研究了该均衡电路的工作模式和控制策略,在此基础上研制了针对4个电池单体的均衡实验电路,均衡实验验证了理论分析的正确性和控制策略的有效性,同时,无论电池组在充电、放电,还是静置状态,该均衡器均能保证均衡精确度在20 m V以内。

Traditional centralized battery equalizer is comprised by coupled-inductor or multi-winding transformer. It has disadvantages of large size, low equalization precision and hard to extend. Besides, distributed equalizer has disadvantages of high cost and too many components. In order to solve the prob-lems, a single-inductor bidirectional cell to cell equalizer based on Buck-Boost converter and switch ma-trix is proposed. Independent regulation was achieved in this equalizer by multiplexing the single induc-tor. Inductor current operated in discontinuous conduction mode ( DCM), and eliminated the cross-regu-lation of each cell. Control strategy and corresponding characteristics were analyzed in this paper. Experi-mental results of a four-battery equalizer are presented to verify the analysis results and control strategy, which indicates that the equalizer can guarantee the equalization accuracy within 20mV whether the bat-tery pack in charging , discharging or static state.