Low-Frequency Selection Switch Based Cell-to-Cell Battery Voltage Equalizer With Reduced Switch Count

A selection switch based cell-to-cell voltage equalizer requires only one dual-port dc-dc converter shared by all the cells. is proposed that utilizes a capacitively level-shifted Cuk and low-frequency cell switches. The absence of isolation transformer diodes in leads to high efficiency, use switches significantly reduces cost drive circuits. network using bipolar buses, where count almost half, compared existing equalizers for case large number novel approach recovery compensation proposed, which operations equalization time. implemented with relays verified an eight-cell Li-ion stack. developed prototype shows efficiency over 90% good balancing performance during charging, discharging, varying load conditions. Experimental results also show about order magnitude reduction relay switchings significant time compensation.