Title :
Rotor demagnetization diagnosis in five-phase surface-mounted permanent magnet generators under time-varying conditions
Author :
Gritli, Y. ; Tani, A. ; Mengoni, Michele ; Zarri, Luca ; Serra, Giovanni ; Filippetti, Fiorenzo ; Casadei, Domenico
Author_Institution :
Dipt. di Ing. dell´Energia Elettr. e dell´Inf. Guglielmo Marconi, Univ. of Bologna, Bologna, Italy
Abstract :
Multiphase Permanent-Magnet Generators are an attractive alternative to induction machines for a variety of applications owing to their reliability and dynamic performance, suited for emerging applications such as automotive or traction systems. In this context, diagnosing the status of the rotor magnets is crucial for improving the reliability of the generators. This paper is focused on the demagnetization of the rotor magnet trailing edges, due to large stator currents, in five-phase surface-mounted permanent magnet synchronous generators under Time-varying conditions. In this context, the classical application of Fourier analysis for processing the back-emf induced in the α-β planes fails as the fault components intended to be monitored to assess the magnets status are spread in a bandwidth proportional to the speed variation. In this paper, a simple and effective method based on Wavelet Transform analysis of the back-emf induced in the α-β planes is presented, that allows the diagnosis of rotor demagnetization for multiphase surface-mounted permanent magnet generator under speed-varying conditions. The proposed approach is validated by means of two dimensional (2-D) Finite Element Analysis (FEA) and numerical simulations. Moreover, a fault index, periodically calculated, is introduced to assess the healthy condition of the machine.
Keywords :
Fourier analysis; demagnetisation; electric potential; fault diagnosis; finite element analysis; permanent magnet generators; reliability; rotors; stators; surface mount technology; synchronous generators; wavelet transforms; α-β plane; 2D FEA; Fourier analysis; automotive system; back-emf processing; five-phase surface-mounted permanent magnet synchronous generator; induction machine; multiphase permanent-magnet generator; numerical simulation; reliability; rotor demagnetization diagnosis; speed-varying condition; stator current; time-varying condition; traction system; two dimensional finite element analysis; wavelet transform analysis; Demagnetization; Harmonic analysis; Magnetic domains; Magnetic flux; Rotors; Stator windings; Vectors; Five-phase Permanent magnet generators; fault diagnosis; permanent magnets; wavelet transform;
Conference_Titel :
Clean Electrical Power (ICCEP), 2013 International Conference on
Conference_Location :
Alghero
Print_ISBN :
978-1-4673-4429-6
DOI :
10.1109/ICCEP.2013.6586923