Conducted EMI Emissions in SPWM based Control Modular Multilevel Converters

In Low Voltage (LV) and Medium Voltage (MV) networks, specific power converters, namely the modular multilevel converters (MMC), need to be in-place to aggregate the renewable energy sources and provide an interface to the distribution electric network (grid). In addition, these multilevel converters can also be used as point-to-point interface in HVDC transmission networks. This paper presents an investigation of the conducted EMI emissions in MMC converters and provides an appropriate filtering solution to reduce the ground current and the stray capacitor voltage. It points out the merit of the selecting the Sub-harmonics SPWM technique as the preferred techniques base on the harmonics cancellations inherent in the control method. A 9-level MMC has been simulated using Matlab-Simpower toolbox. The results have been provided to verify the effectiveness of the EMI filtering method.