Magnet Losses and Demagnetisation in a Permanent Magnet In-wheel Electric Vehicle Traction Motor

Yang, S; Baker, NJ; Mecrow, BC; Smith, D; Atkinson, G; Hilton, C; Perovic, DK; Kakavas, I; Sooriyakumar, G; Harvey, P

doi:10.1109/IEMDC.2015.7409313

Magnet Losses and Demagnetisation in a Permanent Magnet In-wheel Electric Vehicle Traction Motor

Lookup NU author(s): Sichao Yang, Professor Nick Baker ORCiD, Professor Barrie Mecrow, Daniel Smith, Dr Glynn Atkinson

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This is the authors' accepted manuscript of a conference proceedings (inc. abstract) that has been published in its final definitive form by IEEE, 2015.

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Abstract

This paper investigates magnet topologies and their susceptibility to demagnetisation in an in-wheel motor for an electric vehicle. The analysed motor is a high torque density, low speed, surface-mounted permanent magnet (SMPM) modular motor with fractional slot concentrated winding (FSCW) and an outer rotor. The rich spatial stator MMF harmonics present in the air gap have two effects: they generate AC losses in the magnets and they can increase the peak demagnetising field which the magnets experience. In this work, methods are first developed to give greater insight into the magnet loss mechanisms, thereby indicating when magnet segmentation is beneficial. The methods are then extended to examine how different rotor designs are affected by both loss and demagnetisation fields, showing major differences between rotor topologies.[1]