Equalization circuit based on switched‐capacitor units and graph networks for series‐connected cell strings

Abstract

SummaryAn analysis and design method of the equalization circuit based on switched‐capacitor (SC) units and graph networks is proposed in this paper. In the analysis method, the SC equalization circuit is decomposed into multiple SC units and one or more graph networks, which can simplify the analysis process. The effects of circuit parameters and structure on the equalization performance are analyzed in detail. And the average resistance distance among cells is proposed to mathematically analyze and compare the equalization path of the SC equalization circuits. Based on four types of SC units and graph networks of the equalization circuit, a design method of the SC equalization circuit and two SC equalization circuits are proposed. The proposed SC equalization circuit based on cell equalization units has the optimal equalization speed. The proposed SC equalization circuit based on cell equalization units and substring equalization units implements the trade‐off between equalization speed and device number. Simulation and experimental results are provided to verify the validity of the proposed analysis method and SC equalization circuits.