Energy calculation of a permanent magnet system by surface and flux integrals (the flux-mmf method)

Author

Watterson, Peter A.

Author_Institution

Fac. of Eng., Univ. of Technol., Sydney, NSW, Australia

Volume

36

Issue

2

fYear

2000

fDate

3/1/2000 12:00:00 AM

Firstpage

470

Lastpage

475

Abstract

Formulas are derived for the total magnetic energy of a system with no currents, linear soft magnetic materials, and linear permanent magnets that satisfy a zero curl condition involving their magnetization vector (zero equivalent volume current density). This class of magnets includes common parallel and radially magnetized NdFeB and ferrite magnets above the knee in their demagnetization curves. The formulas express the energy as a constant plus either an integral over the magnet surface of the magnetic vector potential or an integral through the magnet of the magnetic flux. The formulas provide theoretical foundation for the flux-magnetomotive force (mmf) method for calculating cogging torque of permanent magnet motors

Keywords

demagnetisation; magnetic flux; magnetisation; permanent magnets; soft magnetic materials; NdFeB; cogging torque; demagnetization curves; energy calculation; ferrite magnets; flux integrals; flux-magnetomotive force; flux-mmf method; linear permanent magnets; linear soft magnetic materials; magnetization vector; permanent magnet motors; permanent magnet system; surface integrals; total magnetic energy; zero curl condition; zero equivalent volume current density; Current density; Demagnetization; Ferrites; Forging; Knee; Magnetic flux; Magnetization; Permanent magnets; Soft magnetic materials; Vectors;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.825815

Filename

825815