Improved Space Vector Modulation Strategies for High-Speed PMSM Fed by a SiC/Si Hybrid Inverter

The switching frequency of the inverter is limited by the switching losses. However, the low switching frequency will cause severe current ripple in high-speed permanent magnet synchronous motor (HSPMSM) drive system. In this paper, two improved space vector modulation strategies based on a silicon- carbide/silicon (SiC/Si) hybrid inverter are proposed to reduce the power losses of the drive system. The SiC/Si hybrid inverter consists of a SiC-MOSFET, a fast recovery diode and six Si- IGBTs. In the proposed strategies, the SiC-MOSFET can generate the zero bus-voltage which can replace the zero-voltage-vectors, so the switching number of Si-IGBTs is significantly reduced. Furthermore, the SiC-MOSFET can create the zero-voltage switching (ZVS) condition for Si-IGBTs, and then the switching losses of Si-IGBTs can be further reduced. The two modulation strategies reduce the power losses and increase available switching frequency of the inverter, making the hybrid inverter more efficient at the high switching frequency. The device-level co- simulation results verify the effectiveness and superiority of the proposed strategies.