Non-Uniform Global Demagnetization Detection in Interior PMSMs Using Search Coils

Abstract

Magnet demagnetization in permanent magnet synchronous machines (PMSMs) can lead to a reduction of the machine torque output and to an increase of the torque ripple, motor vibration and acoustic noise. Permanent magnet (PM) demagnetization detection is therefore a highly appealing feature. Local and global demagnetization patterns can be distinguished, the latter being the most likely to occur; both patterns can be uniform or non-uniform. Non-uniform global demagnetization of the PMs typically occurs due to a combination of high current and high PM temperature. This paper proposes the use of a search coil (SC) to detect and quantify non-uniform global demagnetization faults in interior PMSMs (IPMSMs). Magnitude and phase of the fundamental harmonic component of the SC flux linkage will be used with this purpose. Three different IPMSMs (integer slot, fractional slot, and concentrated winding IPMSMs) will be used to prove the validity of the proposed method. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> This work was supported in part by the Research, Technological, Development and Innovation Programs of the Spanish Ministry of Science and Innovation, under grant PID2019-106057RB-I00.