Modelling and identification of iron losses in nonoriented steel laminations using Preisach theory

A numerical method for the evaluation of magnetic iron losses in steel laminations used in electrical machines is described. The magnetodynamic model for the magnetic field strength H, derived from the Maxwell equations, is coupled with the Preisach theory, describing the hysteresis behaviour. The resulting highly nonlinear and transient boundary value problem for H is solved numerically by a modified finite-element, finite-difference method. The direct identification of the material parameters, for which the authors invoke the Everett theory, is discussed in detail. The model is validated by the comparison of numerical experiments and measurements for the B-H loops. For the material considered the rate-dependent Preisach model is found to be more reliable than the classical Preisach model.