Analysis of a Six-Phase Direct-Drive Permanent Magnet Synchronous Motor with Novel Toroidal Windings

The six-phase direct-drive (DD) permanent magnet synchronous motor (PMSM) has the advantages of low voltage, high power, low speed and high torque, and has a good prospect in electric vehicles, ship propulsion, aerospace and other fields. In this paper, a six-phase DDPMSM with novel toroidal winding (NTW) is proposed. Each coil of the NTWs is wound onto the stator yoke in the same direction, which is different from traditional overlapping windings. The topology of the proposed motor is introduced, and its operation principle is analyzed by describing the variation of the magnetic field produced by the six- phase NTWs versus time. Furthermore, based on the same power grade and effective volume, two six-phase PMSM with different windings are designed. The magnetic field distribution, back-EMF, cogging torque, torque, and loss characteristics are studied in detail. The results show that compared with the traditional six-phase permanent magnet synchronous motor the proposed six-phase DDPMSM with NTWs has the characteristics of low speed and high torque that are desirable for direct-drive systems.