Numerical Homogenization for the Calculation of Eddy Current Losses in a Laminated Open Core

Abstract

Eddy currents are decoupled into narrow eddy currents, induced by the magnetic flux tangential to the laminations, and planar eddy currents, induced by the magnetic flux perpendicular to the laminations. A numerical homogenization procedure is presented for modeling narrow eddy currents, which is performed through computationally cheap 2D simulations in the preprocessing phase. This provides the equivalent magnetic reluctivity function of the core, taking into account the fringing effects of the eddy currents without introducing additional degrees of freedom. This allows for the utilization of a coarse mesh within the laminated core. The validity of the numerical homogenization procedure has been confirmed by comparison with the reference solution. Also, a 3D formulation for calculating losses due to eddy currents in an open core has been derived, which is compatible with the described numerical homogenization procedure.

Keywords

• FEM
• eddy currents
• homogenization
• lamination
• open cores
• transformers