Common-Mode Voltage Reduction Method for MMC with Pulse Sequential Connection Asymmetric Carrier Disposition PWM

In modular multilevel converter (MMC), the switching behavior of submodules (SMs) will cause the high frequency fluctuation of the common-mode voltage, which may cause serious electromagnetic interference (EMI) problems. In this paper, a pulse sequential connection asymmetric carrier disposition sinusoidal pulse width modulation (PSC-ACD-SPWM) strategy is firstly proposed for MMC to eliminate the fluctuation of the common-mode voltage, which can further suppress the EMI of MMC effectively. Compared with other common-mode EMI suppression modulation strategies, the proposed PSC-ACD-SPWM has a higher utilization rate of DC voltage with the same common-mode EMI suppression effect. A five-level MMC simulation model is established to verify the feasibility and effectiveness of the proposed modulation strategy.