Control Strategy of Arm Multiplexing Modular Multilevel Converter under AC Fault

Due to the extensive application of modular multilevel converters in flexible DC transmission systems, the demand for lightweight MMC in modern power systems is gradually emerging as a result of the challenges posed by the large equipment volume and high operational costs. The arm multiplexing modular multilevel converter can effectively achieve lightweighting and improve the utilization of submodules, but due to its complex topology and the fluctuation of internal energy easily affected by operating conditions, the fault crossing ability in the event of AC system faults still needs to be studied. This article adopts amplitude limiting control to inhibit the output current of the converter during faults, and puts forward an approach for controlling current limits aimed at suppressing the negative sequence electrical component generated during asymmetric faults, effectively solving the fault crossing problem of AM-MMC. Ultimately, the simulation is utilized to confirm the proposed strategy’s effectiveness.