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High-Performance Low-Cost Electric Motor for Electric Vehicles Using Ferrite Magnets

Lookup NU author(s): Dr Kia Kimiabeigi, Dr James Widmer, Dr Richard Martin, Dr Timothy Lisle, Professor Barrie Mecrow



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Institute of Electrical and Electronics Engineers, 2016.

For re-use rights please refer to the publisher's terms and conditions.


Permanent-magnet motors with rare-earth magnets are among the best candidates for high-performance applications such as automotive applications. However, due to their cost and risks relating to the security of supply, alternative solutions such as ferrite magnets have recently become popular. In this paper, the two major design challenges of using ferrite magnets for a high-torque-density and high-speed application, i.e., their low remanent flux density and low coercivity, are addressed. It is shown that a spoke-type design utilizing a distributed winding may overcome the torque density challenge due to a simultaneous flux concentration and a reluctance torque possibility. Furthermore, the demagnetization challenge can be overcome through the careful optimization of the rotor structure, with the inclusion of nonmagnetic voids on the top and bottom of the magnets. To meet the challenges of a high-speed operation, an extensive rotor structural analysis has been undertaken, during which electromagnetics and manufacturing tolerances are taken into account. Electromagnetic studies are validated through the testing of a prototype, which is custom built for static torque and demagnetization evaluation. The disclosed motor design surpasses the state-of-the-art performance and cost, merging the theories into a multidisciplinary product.

Publication metadata

Author(s): Kimiabeigi M, Widmer JD, Long R, Gao Y, Goss J, Martin R, Lisle T, Vizan JMS, Michaelides A, Mecrow B

Publication type: Article

Publication status: Published

Journal: IEEE Transactions on Industrial Electronics

Year: 2016

Volume: 63

Issue: 1

Pages: 113-122

Print publication date: 01/01/2016

Online publication date: 25/08/2015

Acceptance date: 19/06/2015

Date deposited: 15/07/2016

ISSN (print): 0278-0046

ISSN (electronic): 1557-9948

Publisher: Institute of Electrical and Electronics Engineers


DOI: 10.1109/TIE.2015.2472517


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110130Innovate U.K.