Influence of static and dynamic rotor/stator misalignments in axial flux magnetically geared machines

• Main Authors: Mohammed F. Hamad Khatab, Zi-Qiang Zhu, Huayang Li, Yue Liu
• Format: Article
• Language: English
• Published: Wiley 2019-06-01
• Series: The Journal of Engineering
• Subjects: gears; permanent magnet machines; torque; finite element analysis; rotors; magnetic flux; stators; machine performance; static rotor/stator misalignments; dynamic rotor/stator misalignments; axial flux magnetically geared machines; low-speed rotor; rotor/stator axis misalignments; HSR cogging torques; distorted air-gap flux density; machine torque performance; static axis misalignments; dynamic axis misalignments
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8186

Here, static and dynamic (rotating) misalignments between the low-speed rotor (LSR) and the stator of axial flux magnetically geared machines are studied with the aid of 3-D finite element analysis (FEA). The influence of rotor/stator axis misalignments on machine performance in terms of cogging torque, air-gap flux density, and back-EMF is investigated with reference to the fully healthy condition. The results show that the LSR and HSR cogging torques are significantly affected by such misalignments due to distorted air-gap flux density. However, the amplitude and the harmonics of the back-EMF are only slightly changed. Furthermore, the influence of the misalignments on the machine torque performance is investigated. It is shown that the machine torque is significantly reduced when the LSR axis is misaligned with the axis of the stator. Thus, it is concluded that the torque performance of axial flux magnetically geared machines significantly deteriorates under static and dynamic axis misalignments. In addition, the two types of misalignments have similar effects on machine performance.