Design and analysis of an inductor-less cross-coupled voltage equalizer

Abstract

To equalize the imbalance in the state-of-charge (SoC) of lithium-ion cells, we propose a novel inductor-less cross-coupled voltage equalizer for series-connected batteries. Unlike existing symmetrical voltage equalizers using diode switches, the proposed voltage equalizer can balance the voltage of battery cells without a threshold voltage drop, because the diode-less design is realized by the cross-coupled structure. The performance of the proposed voltage equalizer is clarified by theoretical analysis, computer simulations, and breadboard-based experimental tests. The computer simulations and experiments reveal that the proposed voltage equalizer outperforms conventional inductor-less voltage equalizers.