Calculation of losses in laminated ferromagnetic materials

A numerical method for calculation of the power losses of nonlinear laminated ferromagnetic cores is presented. The calculation is made in two subsequent steps. In the first step, the approximate magnetic field distribution in the material is determined assuming a nonlaminated bulk nonlinear ferromagnetic material with anisotropic conductivity. In the second step, the nonlinear ferromagnetic material of the laminated core is replaced to linear material with spatially inhomogeneous permeability. The actual permeability distributions of the lamination are determined based on the magnetic field obtained from the first calculation and the nonlinear B-H curve of the material. In this paper, the outlined method is verified through calculations and measurements made on simple benchmark arrangements. Different methods for assigning the inhomogeneous permeability are also investigated.