Eddy current losses in laminated transformer cores

A finite element method, based on the variational principle, for two-dimensional field configurations is used to evaluate eddy current losses in a sheet of a laminated transformer core assumed to be a linear homogeneous conducting medium. Boundary conditions are imposed in an integral form combined with Neumann conditions. Using this approach, it is not required to evaluate integrals involving the primary entity (the magnetic field strength) in order to evaluate secondary entities (the magnetic flux or the complex power). Results show that power losses depend on geometrical parameters and on the field penetration depth. Comparison was made with results derived from the analytical approach based on the field plane configuration assumption, showing that sufficient accuracy may be obtained by applying the proposed method.