A Transformer Coupled Modular Multi-Active Half Bridge Charge Balancing Architecture in a Lithium-ion Battery Pack for Electric Vehicles

This paper proposes a modular transformer coupled multi-active half bridge (TxMAHB) charge balancing architecture for series connected Lithium ion battery (LIB) applications for Electric Vehicles. Unlike the traditional charge balancing circuits, the proposed modular TxMAHB architecture deals with the ac parameters across the transformer, and has the inherent soft switching ability and helps to reduce the switching losses and improves the efficiency. With the proposed TxMAHB architecture, the balancing time is linear with the initial imbalance in the state of charge (SOC). It is validated through extensive simulations and the results are compared with theoretical calculations for a 48 V, 40 AH Battery Pack designed for a Hybrid Electric Vehicle.