Research on the Topology of the Energy Storage System Employing Modular Multilevel Converter

Currently, the development of new energy exhibits a pattern of concurrent development of centralized and distributed forms high-voltage direct current (HVDC) transmission enables the cross-regional power transmission of large-scale power plants.Meanwhile, the medium-voltage direct current (MVDC) distribution system is well-suited for the flexible connection of distributed generation, energy storage, and electric vehicle loads.This study centers on the applications of the modular multilevel converter (MMC) in two types of systems.Initially, through a comparison of three kinds circuit topologies, the advantages of the MMC in high-voltage and high-power scenarios are elucidated.Subsequently, from the viewpoints of centralized and distributed energy storage, the typical topological structures of the energy storage MMC are systematically reviewed, and the main issues encountered in its applications in HVDC and MVDC are analyzed.Finally, the crucial roles of MMC-based energy storage systems (ESS) in power balancing, inertia support, and voltage/frequency stability regulation are highlighted.The research findings indicate that the MMC holds broad application prospects in future power systems.