A Common-Mode Voltage Suppression Oriented Modulation Method for Modular Multilevel Converters

Modular multilevel converter (MMC) has become the mainstream topology of flexible DC transmission and is widely used in many fields. But since MMC has lots of sub-modules (SMs), power electronic devices will generate high dv/dt and di/dt in the high-frequency switching process, and then generate serious common-mode interference through the parasitic capacitance to ground. By analyzing the traditional nearest level modulation (NLM), this paper proposes a modulation method that divides the area on the basis of the number of ON-state SMs, which is area-division nearest level modulation (ADNLM). Finally, the availability of the proposed method in suppressing the common-mode voltage is verified by comparing the output waveform and common-mode voltage waveform using different methods through simulation.