Research on unbalanced characteristics of axial-varying eccentric rotor based on signal demodulation

• Published in: Mechanical systems and signal processing 2024-11, Vol.220, p.111647, Article 111647
• Main Authors: Song, Yongxing, Liu, Zhengyang, Yu, Yueping, Liu, Jingting
• Format: Article
• Language: English
• Subjects: Axial-varying eccentric rotor; Magnetic flux density; Permanent magnet synchronous motor; Signal demodulation; Three-dimensional finite element; Unbalanced magnetic pull; Vibration
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2024.111647

•The unbalanced magnetic pull (UMP) model of axial-varying eccentric rotor was established with Maxwell stress tensor method.•With the signal demodulation techniques, the frequency modulation of various signals from simulation and experiment was extracted.•Based on the modulation features, the relevance among magnetic flux density, UMP, and vibration acceleration was established. In the presence of non-uniform loads, rotor misalignment emerges as a prevalent fault in permanent magnet synchronous motors (PMSMs), leading to the manifestation of an axial-varying eccentric air–gap. Considering the three-dimensional (3D) nature of magnetic flux under axial-varying eccentric fault, 3D finite element (FE) analysis method was used in this paper. Then, the electromagnetism simulations were conducted to calculate the magnetic flux density and unbalanced magnetic pull (UMP). With the signal demodulation algorithm based on principal component analysis (DPCA), the frequency modulation of various signals from simulation and experiment was extracted. Furthermore, based on the modulation features, the relevance among magnetic flux density, UMP, and vibration acceleration was established with shaft frequency as the link. The coupling of magnetic field and vibration level shown in results was analysis, which provide important theoretical and engineering references for the safe operation of PMSM system and the exact identification of rotor tilting faults.