Variable-Gain State-of-Charge Balancing Method for Smart Battery Packs
Jonathan Silva de Oliveira, Bruno de Araujo Coutinho, Pedro Ivo de Oliveira Tironi, Allan Fagner Cupertino, Erick Matheus da Silveira Brito, Heverton Augusto Pereira · IEEE Access · 2025
This paper investigates state-of-charge (SOC) balancing in battery energy storage systems (BESS) using integrated dc-dc converters, which commonly referred to as smart batteries. Mathematical models are developed for both conventional fixed-gain and proposed variable-gain balancing strategies. In the variable-gain method, the control gain is adapted in real-time based on the instantaneous SOC deviation, enabling faster convergence without compromising dc-link voltage stability. Analytical results demonstrate that the theoretical variable-gain approach achieves balancing up to five times faster than the fixed-gain method. The models are validated through simulations and Controller Hardware-in-the-Loop (C-HIL) experiments. The proposed strategy requires only a firmware update, making it suitable for retrofitting existing systems and applicable across different battery chemistries, including second-life applications.