A centralized local energy storage modular multilevel converter

The energy storage modular multilevel converter (MMC-ES) has been widely studied for its excellent performance in solving the problems of power difference, voltage fluctuation and effective improvement quality grid caused by integration new connection. Aiming at that units traditional distributed MMC-ES are scattered, inconvenient to assemble maintain, complex system control, centralized poor capacity selection flexibility, this paper, a local (MMC-CLES) between is proposed. On premise not affecting advantages MMC-ES, reducing number units, switching loss reduced, SOC (state charge) balance control strategy, large conversion loss, AC side current imbalance connection sources high cost too many solved. Matlab/simulink simulation shows compared with MMC-CLES reduces total 52 devices, under condition three-phase unbalance, effectively suppresses fluctuations, fast realized. unbalance degree 8.16%, harmonic distortion rate 3.11%.