Six-Phase Non-Rare Earth Spoke Interior Permanent Magnet Traction Motor With Concentrated Windings

Conventional interior permanent magnet machines (PM) have been dominant in traction applications due to their high power density, high efficiency, and wide constant power speed range. The interior permanent magnet machines typically use high-strength rare-earth magnets to contribute high torque density. However, the rare-earth magnets have several challenges over the past few years. Both academia and industry have paid much more attention to develop an alternative to reduce or eliminate the use of rare-earth magnets. Ferrite magnets do not include any type of rare-earth materials. The combination of spoke-type rotor design and ferrite magnets provides a solution to eliminate rare-earth magnets since the air-gap flux density can be improved by the flux concentrated effect of the spoke-type design. On the other hand, high reliability is also an important requirement for the next-generation traction drive of electric vehicles. This paper will provide the design, analysis, and performance comparison of a six-phase non-rare earth spoke interior permanent magnet traction motor with concentrated windings configuration.