Time-domain finite-element homogenisation of laminated iron cores with net circulating currents

This paper deals with the time-domain homogenization of laminated cores in 2D or 3D finite element (FE) models of electromagnetic devices, in particular allowing for net circulating current in the laminations (which may result from imperfect or damaged insulation). The homogenization is based on the decomposition of the variation of the induction in the lamination thickness by means of a orthogonal set of polynomial basis functions, in conjunction with the magnetic vector potential (MVP) formulation. The conventional even skin-effect basis functions are linked to net flux, whereas the odd ones are now added so as to allow for net current. The approach is validated through a simple linear 2D test case, although the extension to 3D nonlinear problems is straightforward.