A finite element model for foil winding simulation

Foil windings, inductors consisting of a considerable number of foils with a long rectangular cross-section, give raise to severe meshing problems if one tries to consider all geometrical details. On the other hand, treating the winding as a whole by a solid or stranded conductor model, passes over the particular skin effects occurring in this type of winding. Here, a foil conductor model is developed. An additional discretization of finite elements in the foiled region deals with the voltage variation perpendicular to the foils. The constant current condition is weakly imposed. The foil mesh does not coincide with the geometry nor the magnetic mesh, enabling small meshes and independent mesh refinement. The application to a three-phase foil-winding transformer shows a significant saving of computational time, up to 99 % for the test problem