Models of Hysteresis in Magnetic Cores

Overview & Synopsis

A new method of obtaining physical information about a system of fine ferrite powder, from the hysteresis experienced by a ferromagnetic core as it dissipates energy in an RLC circuit is presented. The models of the magnetization processes are classified in three categories : physical, phenomenological and mixed. Hodgdon developed a purely mathematical model that was tested on magnetization processes in magnetic cores. The values of the model's parameters are calculated from experimental data obtained in a series RLC circuit. The capacitor discharges through the circuit and the core performs a complex magnetization process. The voltage across the capacitor and the current intensity are measured. These magnetization processes could be also simulated with a mixed-type model. The identification methodology of the mixed model requires the measurement of some magnetization curves : the first magnetization curve, the major hysteresis loop, the isothermal remanent magnetization process and the d.c. demagnetization process. In order to preserve the simplicity of the experimental data measurement and to perform the identification of the mixed model, some of the experimental curves required by the identification methodology were simulated with the Hodgdon model. Experiments were performed on soft MnZn ferrite core. The results of the identification are discussed.