EAL, Institut für elektrische Antriebe und Leistungselektronik

Institut für elektrische Antriebe und Leistungselektronik

JKU, Johannes Kepler Universität Linz

Sprache: DE

Publikations Einzelansicht

Analytical Stiffness Calculation for Permanent Magnetic Bearings with Soft Magnetic Materials


Autor(en): Gerald Jungmayr, Edmund Marth, Wolfgang Amrhein, Hans-Joerg Berroth und Frank Jeske
Journal: IEEE Transactions on Magnetics
Jahr: 2014
Band: Volume:PP , Issue: 99, Date of Publication: 11 März 2014
Seite(n): 9
ISSN: 0018-9464
Datei / URL: Digital Object Identifier : 10.1109/TMAG.2014.2310437 http://ieeexplore.ieee.org/search/searchresult.jsp?newsearch=true&queryText=Jungmayr+Gerald&.x=16&.y=18
Zusammenfassung: According to Earnshaw’s theorem, the ratio between axial and radial stiffness is always -2 for pure permanent magnetic configurations with rotational symmetry. Using highly permeable material increases the force and stiffness of permanent magnetic bearings. However, the stiffness in the unstable direction increases more than the stiffness in the stable direction. This paper presents an analytical approach to calculating the axial force and the axial and radial stiffnesses of attractive passive magnetic bearings with back iron. The investigations are based on the method of image charges and show which magnet geometries lead to reasonable axial to radial stiffness ratios. Furthermore, the magnet dimensions achieving maximum force and stiffness per magnet volume are outlined. Finally, the calculation method was applied to the passive magnetic bearing of a magnetically levitated fan, and the analytical results were compared to a finite element analysis.

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