Diagnosis Method for Eccentric Fault Severity of Permanent Magnet Synchronous Generator Based on Bearing Seat Vibration Characteristics

This paper proposes a method for using the vibration characteristics of the permanent magnet synchronous generator (PMSG) bearing seat to identify the severity of radial air-gap eccentricity (RAGE) faults. Through theoretical derivation, the detailed expressions of bearing seat magnetic pull per unit area (MPPUA) and the vibration characteristics of the bearing seat under different RAGE faults are obtained. Then the relationship between the degree of RAGE and the vibration amplitude of the bearing seat is analyzed, and a specific diagnostic method for the degree of RAGE is proposed. The finite element analysis (FEA) based on a four-pole PMSG, and the results are consistent with theoretical calculations. It is shown that the method can accurately identify the degree of RAGE faults, and the diagnostic accuracy for radial static air-gap eccentricity (RSAGE) fault is higher than that for radial dynamic air-gap eccentricity (RDAGE) fault. The research conclusions obtained in this paper can be used as a supplementary criterion for diagnosing the eccentricity of PMSG.