Eddy currents in laminated ferromagnetic materials

An algorithm based on the finite element method capable of treating three-dimensional models of laminated iron cores taking account of both iron and leakage losses should be developed. Iron losses include the eddy current and hysteresis losses caused in the laminations by magnetic fields parallel to the sheets whereas leakage losses occur due to magnetic leakage fields with an appreciable normal component with respect to the laminations. Leakage losses will be analysed by a finite element model assuming an anisotropic conductivity or a single current vector potential and resulting in the eddy currents confined to flow essentially parallel to the laminations. This simulation will be carried out with saturation taken into account. Both time domain (transient) and frequency domain models will be developed. The analysis results in an overall field distribution. In a second step, a perturbation of the above overall field distribution by the extremely narrow eddy current loops due to the magnetic fields parallel to the sheets will be taken into account. To this end, three-dimensional analytical models are intended to be established providing both for nonlinearity and hysteresis. The algorithm to be developed is expected to require the same computational effort which is necessary to carry out a three-dimensional eddy current analysis in the iron cores with the same geometry but not laminated. The results will be benchmarked against c...(this text has been cut automatically)