Detection of Partial Demagnetization Faults in Five-Phase Permanent Magnet Assisted Synchronous Reluctance Machines

Abstract

<jats:p>This paper analyzes partial demagnetization faults in a five-phase permanent magnet assisted synchronous reluctance motor (fPMa-SynRM) incorporating ferrite permanent magnets (PMs). These faults are relevant because of the application of field weakening, or due to high operating temperatures or short circuit currents, the PMs can become irreversibly demagnetized, thus affecting the performance and safe operation of the machine. This paper proposes fault indicators to detect such fault modes with low demagnetization levels between 5.0% to 16.7% relative demagnetization. Four partial demagnetization fault detection methods are tested, which are based on the analysis of the harmonic content of the electromotive force (EMF) under no load conditions, the harmonic content of the line currents, the harmonic content of the zero-sequence voltage component (ZSVC) and the analysis of the power factor (PF). This work also compares the sensitivity and performance of the proposed detection methods. According to the fault indicators proposed in this paper, the results show that the analysis of the EMF, ZSVC and PF are the most sensitive detection methods. Experimental results are presented to validate finite element analysis (FEA) simulations.</jats:p>

Recent Developments in Electrical Machine Design for the Electrification of Industrial and Transportation Systems

“…In addition, in ferrite magnets, demagnetization is more difficult to detect, as weaker magnets have a lower impact on the machine performance than rare-earth magnets. In [13], the authors analyze online methods to identify partial demagnetization faults in a five-phase ferrite permanent magnet-assisted synchronous reluctance motor (fPMa-SynRM) shown in Figure 5a. These faults decrease the strength of the magnets and impact the machine's overall performance.…”

An observer design for the flux of line start permanent magnet synchronous motors

“…For the permanent magnet synchronous motor (PMSM) in general, many detection methods for the demagnetization of PMs have been proposed, for instance, the techniques based on the spectral analysis of output data [10], [11]; the method using high-frequency signal injection [12]. Other methods are based on flux observer [13], [14], [15] that allow carrying out on-line detection technologies.…”

Analytical Modeling and Analysis of Permanent-Magnet Motor with Demagnetization Fault

“…(1) The signal-based fault diagnosis method extracts the fault characteristics from the measured signals such as voltage [ 6 , 7 , 8 ], current [ 6 , 7 , 9 , 10 ], flux [ 11 , 12 ], and torque [ 13 ] of the motor for fault diagnosis using signal processing techniques. In [ 6 ], harmonic analysis was carried out on signals such as no-load back-EMF, line current, and the zero-sequence voltage component of the motor with demagnetization faults, and the differences in the harmonic content of various signals between the healthy motor and the partially demagnetized motor were calculated; this served as the basis for diagnosing demagnetization faults. In [ 11 ], rotor eccentricity fault and partial demagnetization fault were diagnosed using the directly measured magnetic flux inside the motor.…”