Modeling the Degradation of Relative Permeability in Soft Magnetic Materials

Soft magnetic material in manufactured electrical machines may have quite different material properties than expected. As known, the manufacturing processes such as cutting, welding or assembly introduce local mechanical or thermal stress into the material which results in a decrease of magnetic permeability and an increase of hysteresis losses. This paper deals with effective modeling the decadence of relative permeability in soft magnetic materials due to manufacturing process. Despite the non-linear characteristic of the relative permeability degradation, the proposed approach uses only one parameter to describe the degradation profile. This simplified but easy to use approach is particularly relevant when the model is implemented in numerical simulation tool. The activity is based on experimental approach and it is supported by analytical and numerical simulations.