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Showing 2 results for Demagnetization
Investigation of Demagnetization Effect in an Interior V-Shaped Magnet Synchronous Motor at Dynamic and Static Conditions
F. Mahmouditabar, A. Vahedi, P. Ojaghlu,
Volume 14, Issue 1 (3-2018)
Abstract
Permanent magnet motors have been considered for a variety of applications due to their features such as high power density and high efficiency. One of the issues that should be investigated in the design of these motors is the demagnetization problem. Usually, the demagnetization analysis is carried out in a steady state, while demagnetization effect in dynamic condition is more considerable due to pulse shaped of armature field. Based on this fact, in this paper, dynamic demagnetization is investigated for an IPM V‑shaped magnet. This study has been done for two types of magnet, each one in static & dynamic conditions and the results are compared. Moreover, the effect of flux weakening regime on demagnetization is investigated.

An Effective Hilbert–Huang Transform-Based Approach for Partial Demagnetization Fault Diagnosis in Double-Rotor Double-Sided Stator Structure Axial Flux Permanent Magnet Generator under Various Load and Speed Conditions
Makan Torabi, Yousef Alinejad-Beromi,
Volume 19, Issue 4 (12-2023)
Abstract
A double-sided axial flux Permanent Magnet (PM) generator which can be directly driven by small-scale low-speed turbines is highly suitable for use in renewable energy generation systems. Partial demagnetization is a failure occurring under the high thermal operation of a Permanent Magnet machine. This paper focuses on partial demagnetization fault diagnosis in a double-rotor double-sided axial flux PM generator using stator currents analysis under time-varying conditions. One of the most important problems in any fault diagnosis approach is the investigation of load and speed variation on the proposed indices. To overcome the aforementioned problems, this paper adopts a novelty detection algorithm based on the Hilbert–Huang transform for fault diagnosis. This approach relies on two steps: estimating the intrinsic mode functions (IMFs) by the empirical mode decomposition (EMD) and computing the instantaneous amplitude (IA) and Instantaneous Frequency (IF) of IMFs using the Hilbert transform. The more significant IMFs are determined using the Hilbert spectrum, which is applied for accurate fault diagnosis. The Partial demagnetization severity can be evaluated based on the IMF’s energy value. The theoretical basis of the proposed method is presented. The effectiveness of the proposed method is verified by a series of simulation and experimental tests under different conditions.
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© 2022 by the authors. Licensee IUST, Tehran, Iran. This is an open access journal distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.