Permanent Magnet Reduction by Current Harmonics Injection for Surface Permanent Magnet Machines

De Gaetano, Daniele; Sala, Giacomo; Degano, Michele; Gerada, Chris

Abstract

This paper presents the analysis of multi-harmonic current injection in multi-three phase surface permanent magnet (SPM) machines. An analytical model, extended to a generic harmonic order, is used to describe and determine the no load flux density, the back electromotive force (BEMF) and the electromagnetic torque produced. These are analysed as a function of the permanent magnet span. Based on the BEMF, the harmonics injection technique is adopted to increase the torque in the machine, while keeping the RMS current constant, thus without affecting the Joule losses. In order to understand how the torque is affected by the harmonics injection, considering different PMs rotor span, a comparison with and without injection is presented. It is shown how, thanks to specific harmonics injection, it is possible to reduce the permanent magnet content in SPM machines while generating the same torque performance of a motor with higher PM content, without harmonic injection. The analytical results are finally validated by means of Finite Element Analysis (FEA) considering two different PM rotor span, as a case study, highlighting the benefits of the proposed method.

Citation

De Gaetano, D., Sala, G., Degano, M., & Gerada, C. (2021). Permanent Magnet Reduction by Current Harmonics Injection for Surface Permanent Magnet Machines. In 2021 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD) (137-142). https://doi.org/10.1109/wemdcd51469.2021.9425662

• Conference Name: IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD 2021)
• Conference Location: Modena, Italy
• Start Date: Apr 8, 2021
• End Date: Apr 9, 2021
• Acceptance Date: Mar 1, 2021
• Online Publication Date: May 11, 2021
• Publication Date: Apr 8, 2021
• Deposit Date: Jul 2, 2021
• Publicly Available Date: Jul 2, 2021
• Pages: 137-142
• Series Title: IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD)
• Book Title: 2021 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD)
• ISBN: 9781728176154
• DOI: https://doi.org/10.1109/wemdcd51469.2021.9425662
• Public URL: https://nottingham-repository.worktribe.com/output/5751856
• Publisher URL: https://ieeexplore.ieee.org/document/9425662
• Additional Information: © 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.