Dynamic Model of Soft Ferrites for Avionic Applications

A simplified dynamic model to represent the behaviour of soft ferrites at higher frequency is necessary in many applications including avionics. We have tried to address this issue by using a circuital model. The model represents frequency dependence of hysteresis in ferrite material using the parallel combination of static hysteresis model and passive electrical elements. The static hysteresis model such as preisach model represents the magnetic core behaviour, whereas the passive electrical elements represent the broadening of hysteresis loops with the increase in frequency. The parameters of the model are identified using pattern search algorithm, and the model is tested for the frequency upto one Megahertz. Comparison between the results obtained from simulation and measurements for N30 Manganese Zinc ferrite using sinusoidal excitation are presented in the paper. The model is applicable to predict the performance of ferrite core inductors that are used to mitigate the lightning indirect effects in avionic equipments.