CUED Publications database

Reduced Dysprosium Permanent Magnets and Their Applications in Electric Vehicle Traction Motors

Chen, L and Hopkinson, D and Wang, J and Cockburn, A and Sparkes, M and O'Neill, W (2015) Reduced Dysprosium Permanent Magnets and Their Applications in Electric Vehicle Traction Motors. IEEE Transactions on Magnetics, 51. ISSN 0018-9464

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Abstract

© 2015 IEEE. Permanent magnet (PM) machines employing rare-earth magnets are receiving increasing interest in electrical vehicle (EV) traction applications. However, a significant drawback of PM machine-based EV tractions is the extremely high cost and volatile supply of rare-earth materials, especially for dysprosium (Dy), whose price is almost 6 times higher than neodymium. This paper describes a new Dy grain boundary-diffusion process for sintered Nd 2 Fe 14 B magnets to maximize its effect on coercivity enhancement. The new process gains an 81% reduction in Dy consumption normally required by the conventional Nd 2 Fe 14 B magnets for the equivalent performance and 17% higher remanence. The investigation into the application in an interior PM (IPM) machine for a small-sized EV traction shows that compared with the conventional Nd 2 Fe 14 B magnets, despite the relatively low coercivity, the low-Dy-content magnets still withstand the thermal and demagnetization challenge over various driving operations. In addition, with the magnet's high remanence and energy product, the machine gains significant torque and energy efficiency improvements. The analysis results are validated by a series of tests carried out on a prototype IPM machine with the new magnets.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div E > Production Processes
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:21
Last Modified: 08 Aug 2017 01:52
DOI: