Linear Analysis of Active Battery Management System for Electric Vehicle using a Switch Matrix with Capacitive Topology

Electric vehicles (EVs) use rechargeable battery packs to power their motors. However, proper battery management can impair long-term battery performance and range. An active battery management system (BMS) with charge equalization capabilities is critical to prevent premature battery failure and enable optimal EV range and performance. This work presents the development of an active BMS using a switch matrix topology with capacitive energy transfer to equalize lead-acid batteries. Three lead-acid batteries are configured in series to provide 36V to represent an EV battery pack. Simulations and experiments validate the use of two-way switches, controlled alternately to shuttle energy from the most-charged battery to the least-charged battery via a shared equalization capacitor until the batteries converge to an equal state of charge. Test results demonstrate successful equalization between batteries and the effectiveness of the BMS at mitigating premature battery failure. The developed system yields a practical solution for active battery management and charge equalization in electric vehicles.