Capacitor-Voltage Ripple Control and Capacitance Reduction Potential of the Auxiliary MMC in a Series-Connected DRU–MMC Offshore HVDC System
This paper develops a capacitor-voltage ripple-control scheme that combines negative-sequence second-harmonic capacitor-voltage feedback with third-harmonic zero-sequence voltage injection. An arm-energy model incorporates the common dc current, auxiliary-MMC voltage allocation, and ac support duty. The dc-series conne...