A time-domain homogenization technique for laminated iron cores in 3-D finite-element models

The authors present a novel time-domain homogenization technique for laminated iron cores in three-dimensional (3-D) FE models of electromagnetic devices when using the magnetic vector potential formulation. The method is based on a polynomial orthogonal decomposition of the variation of the induction throughout the thickness of the laminations. The nonconstant components, due to skin effect, produce additional degrees of freedom and equations for the homogenized core. Insulating layers of finite width between the laminations (fill factor < 1) are taken into account as well. A linear 3-D axisymmetric test case is considered. The results agree well with those obtained with the reference model, in which all laminations are finely discretized and the eddy currents are directly modeled