Novel Method for Modelling of Dynamic Hysteresis

The dynamic hysteresis model for magnetic materials presented by Bertotti uses the classical eddy current expression, where the applied field is assumed to penetrate the material homogenously. However, for this to be valid for a material exposed to a field varying with a frequency in the kilohertz range or higher, the material has to be very thin, e.g., a thin laminate, typically thinner than 0.1 mm. In this paper a novel method is presented. The idea is to combine Bertotti´s model with a Cauer circuit and divide the material into a number of sections, each exhibiting different magnitude of magnetic field caused by the eddy current shielding. Furthermore, the eddy currents are modeled by ldquomagnetic inductancesrdquo instead of the classical eddy current expression. This modelling technique yields simulation results that agree very well with measurements.