Comparing the performance of Si IGBT and SiC MOSFET switches in modular multilevel converters for medium voltage PMSM speed control

Modular Multilevel Converters (MMCs) are shown to have a great potential in the area of medium voltage and high power drive applications. However, the foremost concern in such kind of applications is their reliability and controllability, which have not been thoroughly explored yet. This work primarily verifies the feasibility of MMC in a Permanent Magnet Synchronous Motor (PMSM) torque and speed control. MMCs with Si IGBT switches experience performance degradation when they are used in extreme environments, like higher switching frequency, higher blocking voltage and temperature over 200°C. To overcome these shortcomings, a MATLAB/Simulink based model has been designed where SiC MOSFETs replace the conventional Si IGBTs in MMC, and their performances are compared. The physics-based model of the Si IGBT and the SiC MOSFET are used in MATLAB/Simulink in which the parameters are extracted from manufacturer datasheets. The study suggests that the MMC with SiC MOSFETs outperform almost all of the cases due to their superior physical properties compare to Si counterparts.