Analysis and design of composite-structure resonant switched-capacitor voltage equalization topology for series energy storage systems

摘要

Existing voltage equalization topologies based on the switched-capacitor (SC) operate in the hard-switch state with large energy losses and slow balancing speeds. Therefore, a voltage equalization topology derived from a composite-structure resonant switched-capacitor is proposed in this paper. The proposed topology can achieve zero-current operation and modularity, which reduces system loss and cost. Meanwhile, it can provide two equalization paths from one cell to any other cell, which improves its balancing speed. The zero-current operation, equivalent circuit, design guidelines, and modularization designs for the proposed topology are analyzed in detail. An experiment prototype is established. Results obtained with the prototype verify that the proposed equalizer can achieve zero-current switching (ZCS), high balancing efficiency, and decoupling characteristic between the balancing time and the number of storage cells.

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