Stator Current Square Analysis to Discriminate Between Eccentricity and Demagnetization Faults in PMSMs

Abstract

The stator current spectral analysis (MCSA) technique can detect certain signatures indicating the presence of faults. The presence of the eccentricity and demagnetization fault in Permanent Magnet Synchronous Machine (PMSM) is manifested by the creation of harmonics of the same frequency, which complicates the task of detecting and identifying these faults. Hence, it is needed to propose and develop separation techniques. The objective of this paper is to study the contribution and the effectiveness of a new diagnostic approach to discriminate between the fault of demagnetization of the permanent magnets and the fault of eccentricity in the PMSM. This approach is based on tracking the signs of the real and imaginary components of the Fourier transform of the square of one of the three stator currents. Indeed, the spectrum of the square of the harmonics of the line current has carried more information related to the demagnetization fault and the eccentricity fault. These two faults are manifested by the creation of harmonics whose amplitude is greater than the one of the stator current. In order to demonstrate the effectiveness of this new approach, a series of experimental tests are carried out. The results obtained show the effectiveness of the proposed approach to separate the two treated faults.