Diagnosis and discernment between eccentricity and demagnetization faults in PMSM drives

Abstract

This paper proposes a new approach that allows the diagnosis and the ability of discernment between the frequency signatures of eccentricity faults and those of demagnetization in a permanent magnet synchronous motor (PMSM). This approach is based on the application of a very selective band-pass filter in the stator current. A judicious calculation of the parameters of this filter makes it possible to extract only the frequency signatures of searched faults. The use of the relevant information on the magnitude and phase angle of the signatures, obtained by filtering, makes it possible to distinguish between both of the studied faults. The simple monitoring of the plotting in terms of polar coordinates of the combined information (magnitude/phase angle) of the signature’s characteristic of these two faults allows for this discernment. Experimental results show the effectiveness of the proposed approach when it comes to the diagnosis reliability of demagnetization and the eccentricity faults in a PMSM.