Hybridized Modulation Techniques for Common Mode Voltage Mitigation in Star-Connected Five-Phase PMSM Drives

Star-connected 5-phase Permanent Magnet Synchronous Machine (PMSM) drives can be used for a variety of high-performance electromobility applications where power density, reliability and fault tolerance are of great importance. However, as in three-phase systems, they suffer from Common Mode Voltage (CMV) related issues that affect reliability. The progressive introduction of Wide Bandgap (WBG) technologies, operating with very high switching frequencies, will make the CMV problem even more relevant. For this reason, this work investigates carrier-based modulation techniques for CMV mitigation, and proposes two hybridized alternatives that optimize CMV reduction for the whole operating range of the drive. The CMV reduction potential of the modulation techniques is experimentally validated and discussed using a 2.5 kW multiphase platform incorporating Silicon Carbide (SiC) power electronics. A performance analysis is carried out, providing useful information for field engineers which are interested in implementing this type of carrier-based modulation solutions in multiphase systems.