A Lyapunov-Based Control Scheme for DC-Stacked Modular Battery System with Local Power Control

Traditional lithium-ion battery energy storage systems (Li-BESS) are challenged by inter-cluster currents and accelerated capacity degradation, which stem from inherent cell-to-cell inconsistencies in capacity and state of charge (SOC). To ensure operational efficiency, modularity, safety, and flexibility in large-scale applications, a DC-stacked modular architecture with local power control emerges as a promising solution. This architecture enables direct voltage scaling and modular networking by embedding battery units within power submodules. This architecture enhances scalability and fault tolerance while inherently mitigating issues of premature battery aging and SOC imbalance. However, the reliance on local, independent power control for each module poses new system-level challenges, notably ensuring the stability of the series-connected string and maintaining voltage balance among submodules. To overcome the limited robustness of conventional controllers against parameter variations and operational uncertainties, this paper proposes a novel distributed power control strategy. The proposed method uniquely integrates peak current-mode control (PCM) with a Lyapunov-based framework to ensure tight, synchronized regulation of both submodule voltage and battery current in series-connected systems. By applying the Lyapunov direct method, the necessary conditions for global asymptotic stability are rigorously derived, establishing the control boundary that ensures system stability under a wide range of operating conditions, even in the presence of sampling and computational errors. This approach enhances the system's robustness and reliability, making it particularly suitable for practical applications. Simulation and experimental results on a laboratory prototype verify the effectiveness of the proposed approach, demonstrating robust stability and precise current regulation across a wide range of dynamic operating scenarios.