Advancing battery energy storage system: State-of-health aware state-of-charge balancing in multilevel inverters for electric transportation

This research presents an innovative methodology for enhancing battery energy storage systems for electrically powered transportation, utilizing a distinctive cascaded H-bridge multilevel inverter design, termed P-CHBMI. Central to this work is the development of a state-of-health aware state-of-charge (SoH-aware-SoC) balancing technique, which leverages an advanced algorithm integrated with a Proportional-Integral (PI) controller technique to efficiently balance battery cells according to their state-of health (SoH). This technique significantly improves operational efficiency and extends the lifespan of battery systems by intelligently optimizing cell discharge processes. Moreover, this research work delivers a wide range of simulations for the generation of a streamlined control algorithms for the development of the symmetric and asymmetric configuration of the P-CHBMI. Similarly, recommended topology is proficient of equal voltage discharge across battery cells, which is an exclusive property of the conventional cascaded H-bridge topology. The study includes extensive MATLAB/Simulink simulations to validate the superiority of the P-CHBMI and the SoH-aware-SoC balancing method over conventional systems, highlighting substantial enhancements in switch count efficiency, operational flexibility, and battery durability. Further, the practical applicability of the proposed topology is evidenced through a hardware implementation of a symmetric 5-level inverter. This study plays a significant role in the development of the inverter technology particularly in off-grid scenarios such as electric vehicle and aircrafts, keeping the battery efficiency and reliability as a most important factor.