Single-port and multi-port self-reconfigurable battery topologies for dynamic cell balancing

Abstract

Conventional batteries in electric vehicles (EVs) typically have fixed series-parallel configurations and experience issues such as over-charging/over-discharging and under capacity utilization due to cell imbalance. To address this, a novel single-port self-reconfigurable battery topology is proposed in this paper to balance the cells while maintaining stable terminal voltage. The switching circuit of the topology is designed to have high degree of reconfigurability with minimum number of switches. A supercapacitor is incorporated in the switching circuit to assist the battery during reconfiguration, which also enhances the dynamic performance of the battery. Further, the EV motor-drive and auxiliary loads operate at different nominal voltages; which are typically supplied through power electronic converters. To eliminate the need for power electronic DC-DC converters, a multi-port self-reconfigurable battery topology with stable port voltages is proposed, capable of providing different port voltages. The proposed topologies are verified by developing a single-port battery with a nominal voltage of 52 V and a three-port battery with nominal port voltages of 52 V, 24 V and 12 V using MATLAB/Simulink. The simulation results demonstrate the effectiveness of the proposed topologies in addressing cell imbalance issues, ensuring maximum capacity utilization and stable port voltages.