Semi-physical demagnetization model for the temperature dependency of permanent magnets in electrical machines

Abstract

Losses during the operation of electrical machines heat up permanent magnets which in turn changes their demagnetization behavior. An elevation of permanent magnet’s temperature usually correlates to a decreasing remanence and coercivity. The relation between them may become nonlinear. Existing material models either lack of accuracy or are parameterized with a high number of variables. This paper presents a novel semi-physical material model for permanent magnets with a reduced number, physically based independent variables, which enables a transition between a description of linear and nonlinear demagnetization behavior efficiently.