Institute of Electrical and Electronic Engineers (IEEE)
IEEE Transactions on Industry Applications
This article is a contribution to answer the following question: Is it possible to design a permanent magnet machine with the performance expected from rare-earth magnets but at a lower cost? Performance being understood as torque, size, efficiency, demagnetization, and temperature rise together. The question is addressed with a systematic exploration of different interior permanent magnet machine topologies mixing rare-earth and ferrite permanent magnets. The study starts from a production baseline, the Prius 2010 traction motor, with interior magnets placed in a single V pattern. It investigates various rotor designs, most specifically, single V and double V patterns as well as spoke configurations. The stator cross-section design and winding selection are fixed, providing a solid comparison basis from the point of view of machine cooling. For each rotor design, torque potential and machine material cost are assessed, the latter expressed as torque per dollar. A promising configuration was found based on a spoke pattern for which further modeling was performed to assess efficiency as well as mechanical strength and resistance to short circuits and to demagnetization. It reduces the rare-earth magnet volume by over 60%.
Ma, Qingqing; EL-Refaie, Ayman M.; and Lequesne, Bruno, "Low-Cost Interior Permanent Magnet Machine with Multiple Magnet Types" (2020). Electrical and Computer Engineering Faculty Research and Publications. 656.
ADA Accessible Version
Accepted version. IEEE Transactions on Industry Applications, Vol. 56, No. 2 (2020, March-April): 1452-1463. DOI. © 2020 Institute of Electrical and Electronic Engineers (IEEE). Used with permission.