A 3-D magnetic vector potential formulation taking eddy currents in lamination stacks into account

A method is developed to take the eddy currents in lamination stacks into account with the finite-element method using the three-dimensional (3-D) magnetic vector potential magnetodynamic formulation. It consists in converting the stacked laminations into continuums with which terms are associated for considering the eddy-current loops produced by both parallel and perpendicular fluxes. Two levels of accuracy are proposed. The best one is based on an accurate analytical expression of the eddy currents and makes the method adapted to a widefrequency range, i.e., even for low skin depths in the laminations.