Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors

Axial flux motors have gained widespread attention in the field of electric vehicles. The stator may exert a unilateral axial force on the dual rotors under uneven air gaps. The unbalanced magnetic pull can influence the production and processing of the motor, leading to issues such as vibrations, b...

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Main Authors: Guoqing Zhu, Jian Luo
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/18/9/2397
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author Guoqing Zhu
Jian Luo
author_facet Guoqing Zhu
Jian Luo
author_sort Guoqing Zhu
collection DOAJ
description Axial flux motors have gained widespread attention in the field of electric vehicles. The stator may exert a unilateral axial force on the dual rotors under uneven air gaps. The unbalanced magnetic pull can influence the production and processing of the motor, leading to issues such as vibrations, bearing degradation, reduced lifespan, and torque reduction attributed to the bearings. Accurate evaluation of the unilateral magnetic pull can reduce costs associated with bearing protection. For dual-rotor motors, the axial forces of the rotors act in opposite directions with nearly equal magnitudes, resulting in the catastrophic cancellation of unbalanced magnetic pull calculations. A similar phenomenon may occur between coils, introducing computational errors. To avoid these errors, the stator was selected as the computational target for unilateral axial force calculations. The integration domain was defined to encompass the entire air region containing all windings, rather than summing individual force components. This merged integration approach was mathematically validated through the Maxwell stress tensor method. Finally, the obtained stator axial force closely matched the rotor axial force in magnitude, demonstrating the accuracy of the proposed method.
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series Energies
spelling doaj-art-aeb1107361be46acad2b5c5652a601ae2025-08-20T01:50:45ZengMDPI AGEnergies1996-10732025-05-01189239710.3390/en18092397Unbalanced Magnetic Pull Calculation in Ironless Axial Flux MotorsGuoqing Zhu0Jian Luo1School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200444, ChinaSchool of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200444, ChinaAxial flux motors have gained widespread attention in the field of electric vehicles. The stator may exert a unilateral axial force on the dual rotors under uneven air gaps. The unbalanced magnetic pull can influence the production and processing of the motor, leading to issues such as vibrations, bearing degradation, reduced lifespan, and torque reduction attributed to the bearings. Accurate evaluation of the unilateral magnetic pull can reduce costs associated with bearing protection. For dual-rotor motors, the axial forces of the rotors act in opposite directions with nearly equal magnitudes, resulting in the catastrophic cancellation of unbalanced magnetic pull calculations. A similar phenomenon may occur between coils, introducing computational errors. To avoid these errors, the stator was selected as the computational target for unilateral axial force calculations. The integration domain was defined to encompass the entire air region containing all windings, rather than summing individual force components. This merged integration approach was mathematically validated through the Maxwell stress tensor method. Finally, the obtained stator axial force closely matched the rotor axial force in magnitude, demonstrating the accuracy of the proposed method.https://www.mdpi.com/1996-1073/18/9/2397unbalanced magnetic pullaxial flux motorMaxwell stress tensor
spellingShingle Guoqing Zhu
Jian Luo
Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors
Energies
unbalanced magnetic pull
axial flux motor
Maxwell stress tensor
title Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors
title_full Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors
title_fullStr Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors
title_full_unstemmed Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors
title_short Unbalanced Magnetic Pull Calculation in Ironless Axial Flux Motors
title_sort unbalanced magnetic pull calculation in ironless axial flux motors
topic unbalanced magnetic pull
axial flux motor
Maxwell stress tensor
url https://www.mdpi.com/1996-1073/18/9/2397
work_keys_str_mv AT guoqingzhu unbalancedmagneticpullcalculationinironlessaxialfluxmotors
AT jianluo unbalancedmagneticpullcalculationinironlessaxialfluxmotors