An Improved Charging Strategy of Hybrid-MMC

The energy-taking failure and unsuccessful Charging caused by the low charging voltage of the half-bridge sub-module for the hybrid modular multilevel converter (MMC) has affected the system's secure operation. This paper investigates the topology and submodule voltage distribution with half-bridge and full-bridge submodules during uncontrolled charging. Then, an improved charging strategy for the hybrid MMC is proposed and validated by simulation and experiment. The results demonstrate that the proposed charging strategy can efficiently address the half-bridge submodule failure problem in the charging process.