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An Ultra-Lightweight PM Electrical Motor for High-Altitude Platform Applications

Lookup NU author(s): Dr Rafal Wrobel, Dr Tom WernerORCiD, Dr Xu DengORCiD

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).

Abstract

© 1972-2012 IEEE.This paper describes key aspects of the development process of an ultra-lightweight electrical motor for solar-powered high-altitude (20km) platform applications (HAPSs). A radial-flux permanent magnet (PM) machine topology with outer rotor and integrated direct air-cooling is considered here. The mission profile of the analysed solar-powered aircraft calls for a high-torque overload (×2.5) at take-off and a high-efficiency (>95%) at high-altitude cruise operation. Consequently, a fine balance between both operating points needs to be seen when sizing the motor. Effective thermal management of the motor at take-off is critical for achieving a compact motor design. Further to these, the motor design should enable a simple and cost-effective manufacturing and assembly process, which makes use of the lightweight composite materials for all structural elements of the motor assembly. In this work, a careful integration between both active and structural subassemblies of the motor resulted in a significant weight reduction, with contribution of all structural components less than 5% of the overall motor weight. The theoretical and experimental results discussed in the paper confirm the key design targets of the motor are met, with a motor torque density of 10Nm/kg (take-off operation) and 94% efficiency (cruise operation). Further to the motor development process, a comprehensive insight into the existing state of the art HAPS solar-powered aircrafts with focus on the commercial electrical motor technology and motor to aircraft integration is provided to highlight some of the application driven engineering challenges.

Publication metadata

Author(s): Wrobel R, Werner TC, Deng X, Noal D

Publication type: Article

Publication status: Published

Journal: IEEE Transactions on Industry Applications

Year: 2025

Volume: 61

Issue: 6

Pages: 9243-9253

Print publication date: 01/12/2025

Online publication date: 26/06/2025

Acceptance date: 14/06/2025

Date deposited: 04/08/2025

ISSN (print): 0093-9994

ISSN (electronic): 1939-9367

Publisher: IEEE

URL: https://doi.org/10.1109/TIA.2025.3583679

DOI: 10.1109/TIA.2025.3583679

ePrints DOI: 10.57711/axxk-a947

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