Contribution of permanent-magnet volume elements to no-load voltage in machines

• Published in: IEEE transactions on magnetics Vol. 39; no. 3; pp. 1784 - 1792
• Main Authors: Dubois, M.R., Polinder, H., Ferreira, J.A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2003; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Couplings; Design engineering; Design optimization; Electric motors; Electric potential; Electrical engineering. Electrical power engineering; Electrical machines; Exact sciences and technology; Finite element method; Finite element methods; Flux; Geometry; Linkages; Machine windings; Magnetic flux; Magnetism; Mathematical analysis; Optimization; Optimization methods; Product design; Shape; Synchronous machines; Voltage; Winding; Electrical engineering; Magnetic flux; permanent-magnet machines; Cost optimization of machines; Theoretical study; permanent-magnet shaping; Permanent magnet machine; Numerical simulation; no-load voltage; Permanent magnet
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2003.809874

In permanent-magnet (PM) electrical machines, a key role of PM material is to induce a voltage in a winding upon a relative movement of the PM about that winding. Although useful, PMs are costly and machine designers should optimize the contribution of all the volume elements in PMs as much as possible. This paper presents a new mathematical expression for the no-load flux linkage generated by PMs. The mathematical expression gives the flux linkage in terms of the PM geometry. This proves to be efficient in evaluating the contribution of each local magnet volume element to generate a no-load flux linkage. We propose a method that uses the derived mathematical expression to optimize the shape of PMs, and this method is applied to the case of a conventional PM synchronous machine. The optimization process uses the results from finite-element analysis, and the resulting PM shape shows an increase of voltage induced per PM volume.