Topology, Modeling, and Optimization of Switched-Capacitor Equalizer Based on Multiplexing Technology for Multiple Battery Strings

Traditional switched-capacitor equalizers are generally limited to balancing the voltage of a single battery string. In this article, a novel switched-capacitor equalizer based on capacitor network multiplexing technology is proposed, allowing voltage equalization not only within each battery string but also between multiple battery strings. The capacitor network multiplexing is implemented by pulse phase-shift control of the switch arrays, significantly reducing the number of required capacitors. The balancing performance of various capacitor networks is analyzed and compared, and the optimal network is selected. The working principle and modeling method of the proposed equalizer are explained in detail. Theoretical guidance for the parameter design is provided by optimizing the balancing speed and loss. An experimental prototype with two battery strings is developed. The experimental results confirm the feasibility of the proposed equalizer, with an efficiency of 92.89%.