Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures

This study examined the design and optimization of low-speed external frame motors featuring Halbach-type and olive-shaped magnet structures to improve performance in spacecraft control moment gyroscopes (CMGs). Our research was driven by the urgent need for precise, high-torque, low-speed motors in...

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Main Authors: Rana Md Sohel, Youtao Shen, Runze Ji, Kai Liu
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:World Electric Vehicle Journal
Subjects:
Online Access:https://www.mdpi.com/2032-6653/16/7/350
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author Rana Md Sohel
Youtao Shen
Runze Ji
Kai Liu
author_facet Rana Md Sohel
Youtao Shen
Runze Ji
Kai Liu
author_sort Rana Md Sohel
collection DOAJ
description This study examined the design and optimization of low-speed external frame motors featuring Halbach-type and olive-shaped magnet structures to improve performance in spacecraft control moment gyroscopes (CMGs). Our research was driven by the urgent need for precise, high-torque, low-speed motors in CMGs, where conventional designs, including Halbach-type and traditional radial magnet configurations, are hindered by manufacturing complexity and excessive torque pulsation. This study focused on optimizing rotor pole configurations to enhance efficiency and torque stability. An olive-shaped magnet structure provides a more uniform magnetic field distribution in the air gap, substantially reducing magnetic field harmonics and minimizing cogging torque and torque pulsation—critical performance factors for low-speed applications. Comparative analysis reveals that the olive-shaped motor achieves a peak torque of 0.312 N·m with a torque pulsation of 0.9 mN·m, maintaining an amplitude below 0.3%. This demonstrates a 20% improvement compared to the Halbach-type motor’s torque pulsation of 1.15 mN·m. Moreover, the olive-shaped motor exhibits superior stability in air-gap magnetization under different loads, ensuring high efficiency and robust operation. By streamlining magnet assembly while enhancing electromagnetic performance, this study offers a cost-effective, high-precision solution for CMG systems. These findings underscore the olive-shaped magnet motor’s potential to advance motor technology for aerospace applications.
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institution Kabale University
issn 2032-6653
language English
publishDate 2025-06-01
publisher MDPI AG
record_format Article
series World Electric Vehicle Journal
spelling doaj-art-b68a0918e4d843b4922220682c0eea7c2025-08-20T03:32:28ZengMDPI AGWorld Electric Vehicle Journal2032-66532025-06-0116735010.3390/wevj16070350Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet StructuresRana Md Sohel0Youtao Shen1Runze Ji2Kai Liu3School of Electrical Engineering, Southeast University, Nanjing 210096, ChinaShanghai Aerospace Control Technology Institute, Shanghai 201114, ChinaSchool of Electrical Engineering, Southeast University, Nanjing 210096, ChinaSchool of Electrical Engineering, Southeast University, Nanjing 210096, ChinaThis study examined the design and optimization of low-speed external frame motors featuring Halbach-type and olive-shaped magnet structures to improve performance in spacecraft control moment gyroscopes (CMGs). Our research was driven by the urgent need for precise, high-torque, low-speed motors in CMGs, where conventional designs, including Halbach-type and traditional radial magnet configurations, are hindered by manufacturing complexity and excessive torque pulsation. This study focused on optimizing rotor pole configurations to enhance efficiency and torque stability. An olive-shaped magnet structure provides a more uniform magnetic field distribution in the air gap, substantially reducing magnetic field harmonics and minimizing cogging torque and torque pulsation—critical performance factors for low-speed applications. Comparative analysis reveals that the olive-shaped motor achieves a peak torque of 0.312 N·m with a torque pulsation of 0.9 mN·m, maintaining an amplitude below 0.3%. This demonstrates a 20% improvement compared to the Halbach-type motor’s torque pulsation of 1.15 mN·m. Moreover, the olive-shaped motor exhibits superior stability in air-gap magnetization under different loads, ensuring high efficiency and robust operation. By streamlining magnet assembly while enhancing electromagnetic performance, this study offers a cost-effective, high-precision solution for CMG systems. These findings underscore the olive-shaped magnet motor’s potential to advance motor technology for aerospace applications.https://www.mdpi.com/2032-6653/16/7/350Halbach-type motorolive-shaped magnet motorlow-speed external frame motormagnetic field distributiontorque pulsation reductioncmg applications
spellingShingle Rana Md Sohel
Youtao Shen
Runze Ji
Kai Liu
Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures
World Electric Vehicle Journal
Halbach-type motor
olive-shaped magnet motor
low-speed external frame motor
magnetic field distribution
torque pulsation reduction
cmg applications
title Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures
title_full Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures
title_fullStr Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures
title_full_unstemmed Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures
title_short Design and Analysis of Low-Speed External Frame Motors with Halbach-Type and Olive-Shaped Magnet Structures
title_sort design and analysis of low speed external frame motors with halbach type and olive shaped magnet structures
topic Halbach-type motor
olive-shaped magnet motor
low-speed external frame motor
magnetic field distribution
torque pulsation reduction
cmg applications
url https://www.mdpi.com/2032-6653/16/7/350
work_keys_str_mv AT ranamdsohel designandanalysisoflowspeedexternalframemotorswithhalbachtypeandoliveshapedmagnetstructures
AT youtaoshen designandanalysisoflowspeedexternalframemotorswithhalbachtypeandoliveshapedmagnetstructures
AT runzeji designandanalysisoflowspeedexternalframemotorswithhalbachtypeandoliveshapedmagnetstructures
AT kailiu designandanalysisoflowspeedexternalframemotorswithhalbachtypeandoliveshapedmagnetstructures