Power Loss Regulation Based on Capacitor Voltage Shift Control under Centralized Control for MMCs

In modular multilevel converters (MMCs), controlling energy losses in submodules (SMs) power electronics is a key consideration for operational reliability. During normal execution, variations in observable power losses can occur between SMs within the arm, primarily caused by factors such as component aging in power electronics and inconsistencies in module parameter matching, etc. This study introduces a DC voltage shift control-based approach (DVSC-PLR) for regulating power losses. By implementing centralized control in MMCs, the equalization of power losses among SMs can be ensured by making adjustments to the mean capacitor voltage to keep it at a constant value. The proposed DVSC-PLR method successfully ensures balanced power dissipation among all SMs within the MMC arm, thereby improving MMC reliability in centralized control schemes. For validation, this study employs time-domain simulations performed in the specialized software PSCAD/EMTDC. The research results obtained confirm the actual validity of the control tactics.