Low‐cost switched capacitor charge equaliser with cancellation mechanism of alternating current

Abstract

A low-cost switched capacitor charge equaliser with cancellation mechanism of alternating current for electric vehicles is proposed in this study. Among various charge equalisers, the switched capacitor type equaliser is popular due to its simplicity, small volume and low cost. However, the cycle life of battery will be reduced by unnecessary energy transfer since an alternating current flows through the battery without energy change. Hence, a cancellation mechanism of alternating current is presented to deliver energy directly from the source battery to the target battery, which avoids the unnecessary charging and discharging for the battery without energy variations. A low-voltage H-bridge drive integrated circuit (IC) is used to reduce the cost, size and complexity of the proposed equaliser. The circuit topology and operation analysis of the proposed charge equaliser are described in detail. Finally, the experimental results verify the effectiveness and performance of the proposed charge equaliser.