Dual-Loop Quasi-Proportional-Resonant Control with Online Energy Balancing for Modular Multilevel Converters in Residential Energy Storage

This paper investigates a modular multilevel converter based on half-bridge submodules for residential energy storage applications. A dual-loop quasi-proportional-resonant controller with load current feedforward is proposed for precise voltage and current regulation. Additionally, an online energy balancing method based on carrier redistribution is introduced, ensuring balanced energy distribution across submodules without disrupting normal operation. Simulation results demonstrate the effectiveness of the proposed control and balancing strategies, highlighting their suitability for residential energy storage systems.