Detecting Eccentricity Fault in Permanent Magnet Synchronous Machines by Means of Zero-Sequence Voltage Component

Eccentricity is a critical fault in permanent magnet synchronous machines (PMSMs), and can be generally classified into static eccentricity (SE), dynamic eccentricity (DE) and mixed eccentricity (ME). In this article, the fault diagnosis method based on zero-sequence voltage component (ZSVC) is proposed for detecting eccentricity in PMSMs with rotational asymmetric winding configurations. Different types of eccentricity can be classified with different fault characteristic harmonics in the measured ZSVC, which is extracted by Fast Fourier Transform (FFT). Specifically, the fundamental component and sideband harmonics appear under SE and DE, respectively. Both the fault characteristic components show up in case of ME. Notably, the ZSVC difference between two sets of three-phase windings obtains higher sensitivity for detection in dual three-phase PMSMs with rotational asymmetric winding configurations. Furthermore, the influence of eccentricity condition, load condition as well as other faults is investigated. Especially, the effect of d-axis current on fault indicators is revealed from armature flux linkage and PM flux linkage due to different degree of core saturation under eccentricity fault. Finally, the experiment is carried out on 10-pole/9-slot and 10-pole/12-slot surface-mounted single three-phase PMSMs, and the latter one is also connected as different dual three-phase winding configurations for verification.