Common-Mode Voltage Reduction of Modular Multilevel Converter Based on Six-Segment Carrier Level Shifted Sinusoidal Pulse Width Modulation

High frequency fluctuation in common-mode (CM) voltage of the modular multilevel converter (MMC) causes serious CM electromagnetic interference (EMI), which could damage the load motor and shorten its life. In this paper, a six-segment carrier level shifted sinusoidal pulse width modulation (S
²
CLS-SPWM) method is firstly proposed for MMC, in order to keep the CM voltage constant and reduce CM EMI. The operation principle of the S
²
CLS-SPWM is firstly introduced, then a 5-level MMC simulation platform is established based on MATLAB/Simulink. Finally, the correctness and effectiveness of the proposed S
²
CLS-SPWM is verified by the simulation results. This paper provides a new way for solving the CM EMI problem in the MMC.