Demagnetized Magnet Diagnosis in a Double-Layer Winding Permanent Magnet Synchronous Machine using Wavelet Packet Transform

Abstract

Permanent Magnets (PM), which are one of the most vulnerable and important components of permanent magnet machines, are at risk of demagnetization for reasons such as overheating and corrosion. One of the most critical tasks of engineers in the industry is to prevent the machine's operation in the demagnetization condition and replace the machine's defective PMs as much as possible. Demagnetization causes linkage flux reduction, electromagnetic force changes, and machine heating. This paper presents a new approach for demagnetized PM diagnosis in a permanent magnet linear synchronous machine using wavelet packet transform. Due to the high sensitivity to the flux changes, the electromotive force signal was selected as a detection signal.By examining this method in different demagnetization cases, it is determined that this method has a proper performance. In this paper, the finite element software (Maxwell) and MATLAB were used to simulate the machine and analyze the data, respectively.

Keywords

• wavelet packet transform
• permanent magnet
• demagnetization
• linear synchronous machine