Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization
Currently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | Machines |
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| Online Access: | https://www.mdpi.com/2075-1702/9/6/124 |
| _version_ | 1797529474348089344 |
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| author | Dantam Rao Madhan Bagianathan |
| author_facet | Dantam Rao Madhan Bagianathan |
| author_sort | Dantam Rao |
| collection | DOAJ |
| description | Currently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’ in the B(H) curve. We show herein that the classic knee point definition can degrade a magnet by up to 4 grades. To prevent consequent excessive loss in performance, this paper defines the knee point k as the point of intersection of the B(H) curve and a parallel line that limits the reduction in its residual flux density to 1%. We show that operating above such a knee point will not be demagnetizing the magnets. It will also prevent a magnet from degenerating to a lower grade. The flux density at such a knee point, termed <i>demag flux density</i>, characterizes the onset of demagnetization. It rightly reflects the value of a magnet, so can be used as a basis to price the magnets. Including such knee points in the purchase specifications also helps avoid the penalty of getting the performance of a low-grade magnet out of a high-grade magnet. It also facilitates an accurate demagnetization analysis of traction motors in the worst-case conditions. |
| first_indexed | 2024-03-10T10:14:24Z |
| format | Article |
| id | doaj.art-2662ee478ea04539a5edf7239e84c0d3 |
| institution | Directory Open Access Journal |
| issn | 2075-1702 |
| language | English |
| last_indexed | 2024-03-10T10:14:24Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Machines |
| spelling | doaj.art-2662ee478ea04539a5edf7239e84c0d32023-11-22T00:54:14ZengMDPI AGMachines2075-17022021-06-019612410.3390/machines9060124Selection of Optimal Magnets for Traction Motors to Prevent DemagnetizationDantam Rao0Madhan Bagianathan1MagWeb USA, Frisco, TX 75035, USAMAGNA Powertrain GmbH, 2514 Traiskirchen, AustriaCurrently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’ in the B(H) curve. We show herein that the classic knee point definition can degrade a magnet by up to 4 grades. To prevent consequent excessive loss in performance, this paper defines the knee point k as the point of intersection of the B(H) curve and a parallel line that limits the reduction in its residual flux density to 1%. We show that operating above such a knee point will not be demagnetizing the magnets. It will also prevent a magnet from degenerating to a lower grade. The flux density at such a knee point, termed <i>demag flux density</i>, characterizes the onset of demagnetization. It rightly reflects the value of a magnet, so can be used as a basis to price the magnets. Including such knee points in the purchase specifications also helps avoid the penalty of getting the performance of a low-grade magnet out of a high-grade magnet. It also facilitates an accurate demagnetization analysis of traction motors in the worst-case conditions.https://www.mdpi.com/2075-1702/9/6/124traction motorselectric vehicle (EV)permanent magnetsknee pointdemagnetization curvesevere duty |
| spellingShingle | Dantam Rao Madhan Bagianathan Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization Machines traction motors electric vehicle (EV) permanent magnets knee point demagnetization curve severe duty |
| title | Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization |
| title_full | Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization |
| title_fullStr | Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization |
| title_full_unstemmed | Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization |
| title_short | Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization |
| title_sort | selection of optimal magnets for traction motors to prevent demagnetization |
| topic | traction motors electric vehicle (EV) permanent magnets knee point demagnetization curve severe duty |
| url | https://www.mdpi.com/2075-1702/9/6/124 |
| work_keys_str_mv | AT dantamrao selectionofoptimalmagnetsfortractionmotorstopreventdemagnetization AT madhanbagianathan selectionofoptimalmagnetsfortractionmotorstopreventdemagnetization |