A High-Efficiency and Low-Cost Battery Energy Storage System Based on Cascaded Hybrid H-Bridge

This paper proposes a high-efficiency and low-cost battery energy storage system utilizing a cascaded hybrid H-bridge topology. The cascaded hybrid H-bridge consists of a capacitor H-bridge submodule combined with several battery energy storage H-bridge submodules connected in series, leveraging the benefits of cascaded H-bridge designs in terms of modularity and ease of scalability. The switching frequency of the capacitor H-bridge submodule operates at tens of kilohertz, whereas that of the battery energy storage H-bridge submodule operates at twice the grid frequency. This operational mode not only significantly reduces switching losses and enhances system efficiency while maintaining low total harmonic distortion but also decreases system costs by employing power switching devices with longer switching times. Furthermore, this paper introduces a coordinated voltage balancing algorithm designed for the different H-bridge submodules to ensure uniform voltage distribution and prolonged system life. The effectiveness of the proposed topology and control strategies is validated through comprehensive simulation results, demonstrating superior performance in both efficiency, power quality and reliability.