Redistributed Pulsewidth Modulation of MMC Battery Energy Storage System Under Submodule Fault Condition

Battery energy storage system based on the modular multilevel converter (MMC-BESS) is able to realize the decentralized management of battery packs, which is suitable for the retired battery utilization to improve the efficiency of battery recycling. With multiple submodules (SM), the corresponding SM fault ride-through method is mandatory to improve operational reliability. This paper proposes a redistributed pulsewidth modulation method for MMC-BESS to ride-through the SM fault through employing the simple logic operation, which could avoid the unexpected carrier shift under various modulation indexes induced by the SM fault or grid voltage rise. MATLAB simulations and experimental results are presented to verify the performance of the proposed method.