Dual Three Phase Rare-Earth Free Spoke-Type Permanent Magnet Synchronous Traction Motor Using Ferrite Magnets

Abstract

This paper proposes a dual three phase rare-earth free spoke-type ferrite permanent magnet traction motor. First, the machine topology and drive system configuration of the proposed design is illustrated. The design specifications and requirements are introduced. Some key design parameters on torque performance are investigated, including the effect of iron bridges, effect of rotor pole shaping, and rotor skewing. The demagnetization risk of the proposed design is also evaluated. Finally, the open-circuit electromagnetic characteristics and on-load torque capability are predicted by finite element analysis. The performance of the proposed design is compared to the rare-earth interior permanent magnet motor and synchronous reluctance motor. The toque density is competitive to that of rare-earth permanent magnet motor with fractional slot concentrated windings. More importantly, the proposed dual three phase spoke-type ferrite traction motor offers several advantages, including low-cost, non-rare-earth magnets, and fault tolerant.