Optimization of Redundant Number of MMC Submodules in Flexible Control Device

Any submodule of the MMC in the flexible control device in failure will affect the normal operation of the system, thus affecting its reliability. Configuring redundant submodules for the MMC may significantly improve the reliability, but the mutual restriction of the reliability and economy is the key problem in the optimization of the redundant submodules’ number. In this article, the reliability and economy model of the MMC with redundant submodules are established, and the optimization function is established. The NSGAII optimization function are used to realize the optimization respectively. It can significantly improve the economy while meeting the system reliability. It provides ideas for the number allocation of the MMC redundant submodules in the actual MMC-HVDC project.