A Multi-Active-Half-Bridge Converter based Soft-switched Fast Voltage Equalizer for Multi-cell to Multi-cell Charge Transfer

Batteries are connected in series to meet the voltage requirement in many applications. A voltage equalizer circuit is necessary to ensure that none of the batteries is over-charged or over-discharged. A fast soft-switched multi-cell to multi-cell voltage equalizer topology is proposed in this work. This topology can transfer charge from multiple over-charged batteries to multiple under-charged batteries simultaneously to achieve fast voltage equalization. The proposed topology and modulation ensure zero voltage switching under all battery conditions. The circuit operation and soft-switching are analyzed and experimentally verified with a four battery voltage equalizer prototype which validates a high conversion efficiency and performance.