一种LC单元的双向电压均衡电路

Bidirectional voltage equalization circuit based on LC unit

储能系统中通常采用多个单体串联的方式得到更高的电压,针对储能单元单体串联在实际使用中存在各单体电压不一致的问题,提出一种LC单元和双向开关单元相结合的双向电压均衡电路。在工作过程中,该均衡电路先将能量从电压最大的单体转移至电感中,再将能量从电感转移至电压最小的单体,最终达到均衡电压的目的;并且均衡路径长度与充放电单体位置无关,缩短了能量传输路径。该均衡电路仅有一个LC单元,没有大量的磁性元件,并且每增加一个储能单体,该电路只需增加一对开关管,具有体积小和扩展性高的优点。控制策略可实现该均衡电路的精确控制,保证了电路的正常工作。详细的阐述了均衡电路的工作原理,分析其电路特性及控制方法,实验结果验证了理论分析的正确性。

During the use of series-connected energy storage stack, the voltage between energy unit is inconsistent.Therefore, a bidirectional voltage equalizer is presented for series-connected energy storage stack, which combines LC unit and bidirectional switch unit. In the working process, the energy was transferred from the cell with the largest voltage to the inductor, and then the energy was transferred from the inductor to the cell with the lowest voltage, so as to achieve the purpose of voltage equalization. Moreover, the length of the equalization path is independent of the position of the charging and discharging cells, which shortens the energy transmission path.The equalization circuit has only one LC unit, without a large number of magnetic components, and for each additional energy storage unit, the circuit only needs to add a pair of switches, which has the advantages of small size and good extendibility. The control strategy can realize the precise control of the equalization circuit and ensure the normal operation of the circuit. The working principle of the equalization circuit was described in detail, and its circuit characteristics and control methods were analyzed. The experimental results verify the correctness of the theoretical analysis.