Ing. Ivana Nová, Ph.D.

Modelling of dynamic hysteresis loops of soft magnetic materials is carried out by extended hyperbolic model. The extension is based on pure phenomenological approach and consists in elliptical component addition. This component features rounded shapes of dynamic hysteresis loops at low intensities of magnetization and it needs two parameters only. Fitting parameters for each loop are searched individually, and their dependences are then approximated by rational functions. The final model operates with approximated parameters. Proposed model was tested for the material FeNi47Cu5 at sinusoidal excitation at frequency 50 Hz.

The hyperbolic model was extended and tested to find analytical approximation of dynamic hysteresis loops of soft magnetic materials. The extension is based on pure phenomenological approach and consists in new component addition. At first, measured loops were simulated separately and favourable local parameters were searched. Founded parameters depend on excitation level. Afterwards, analytical dependences were searched using simple mathematical functions. The final model operates with estimated parameters and it is able to predict the loop shape and related important parameters at any excitation level within permitted range. The applicability of proposed extension was tested for material FeNi42 at sinusoidal excitation. Experiments show rather good resemblance between measured and simulated dynamic loops.

Analytical inverse model was proposed to find simple mathematical approximation of dynamic hysteresis loops of soft magnetic materials. It consists of three components by means of mathematical functions. Favourable mimicking coefficients were searched, which depend on excitation amplitude and frequency. The nature of its behaviour was studied in order to be able to predict the loop shape. The model was tested for opened specimen of classic silicon electrical steel at sinusoidal excitation, measured by compensation ferrometer.

Analytical model was proposed to find simple mathematical approximation of dynamic hysteresis loops of soft magnetic materials. It is based on pure phenomenological approach and consists in dynamic loop construction from four components by means of mathematical functions. Favourable mimicking coefficients were searched, which depend on excitation amplitude and frequency. The nature of its behaviour was studied in order to be able to predict the loop shape. The model was tested for opened specimen of classic oriented silicon electrical steel at sinusoidal excitation, measured by means of KF9a compensation ferrometer.