Experimental Statistical Method Predicting AC Losses on Random Windings and PWM Effect Evaluation

Preci, Eraldo; Valente, Giorgio; Galassini, Alessandro; Yuan, Xin; Degano, Michele; Gerada, David; Buticchi, Giampaolo; Gerada, Chris

Abstract

Nowadays, one of the challenges in transport electrification is the reduction of the components' size and weight in order to improve the power density. This is often achieved by designing electrical machines with higher rotational speeds and excitation frequencies. In addition, the converter needs to control the machine over a wide speed range given by the mission profile. Therefore, copper losses can significantly increase due to the combination of high frequency excitation and the harmonics introduced by the converter. The winding arrangement design plays a key role in the minimization of the copper losses, thus towards a higher efficiency and/or an improved power density. Different winding topologies can be adopted for high speed electrical machines and amongst them random windings are still one of the most widespread types. This paper presents an in depth study on AC losses in random windings for high frequency motor applications. An analytical method is compared against 2-D Finite Element (FE) simulation results. These are then compared to experimental measurements taken on a custom motorette. Importantly, in order to take into account the random positions of each strand within the machine slots, an Experimental Statistic Method (ESM) is proposed. The ESM allows to define the probability distribution which is useful to evaluate the winding copper losses at the design stage. The contribution of the Pulse Width Modulation (PWM) effect is also considered and experimentally evaluated.

Citation

Preci, E., Valente, G., Galassini, A., Yuan, X., Degano, M., Gerada, D., Buticchi, G., & Gerada, C. (2021). Experimental Statistical Method Predicting AC Losses on Random Windings and PWM Effect Evaluation. IEEE Transactions on Energy Conversion, 36(3), 2287-2296. https://doi.org/10.1109/TEC.2020.3040265

• Journal Article Type: Article
• Acceptance Date: Nov 16, 2020
• Online Publication Date: Nov 24, 2020
• Publication Date: 2021-09
• Deposit Date: Dec 17, 2020
• Publicly Available Date: Jan 6, 2021
• Journal: IEEE Transactions on Energy Conversion
• Print ISSN: 0885-8969
• Electronic ISSN: 1558-0059
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 36
• Issue: 3
• Pages: 2287-2296
• DOI: https://doi.org/10.1109/TEC.2020.3040265
• Keywords: Electrical and Electronic Engineering; Energy Engineering and Power Technology
• Public URL: https://nottingham-repository.worktribe.com/output/5154699
• Publisher URL: https://ieeexplore.ieee.org/document/9268485
• 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.