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Recent advances have been made into modeling the soft-magnetic materials using the surface charge model. Until now, the model has only been used to model the field outside the soft-magnetic material. To include the saturation in the future, the magnetic field inside the material should be known. In this paper, the model is used to calculate the field inside the material when three different shapes of boundaries are considered. Comparing the results with Finite Element Method shows that the differences in the air region are <1 mT and those in the soft-magnetic region are <4 mT. Larger discrepancies can, however, occur near the corner of the material. [ABSTRACT FROM AUTHOR]

This paper presents a vector hysteresis model based on micromagnetic theory. In this model, a magnetization state of a magnetic material is described by a collection of single-domain particles, and magnetic reversal processes due to domain-wall motions are treated approximately as a magnetization flip. The present model is applied to calculation of hysteresis properties of grain-oriented silicon steel. The simulation results show that the anisotropic hysteresis properties and iron loss can be reproduced accurately by the present model. [ABSTRACT FROM AUTHOR]

This paper deals with the mathematical definition of a general vector hysteresis operator in 3-D, as an extension of previous papers where the theory has been limited to the 2-D case. Although the paper is mainly focused on magnetic hysteresis, the definitions and the results reported can be applied to any general physical phenomenon that exhibits hysteresis. We show here the main general properties of the general hysteresis operator in 3-D. [ABSTRACT FROM AUTHOR]

This paper focuses on the thermal stress on magnetic materials under Curie temperature. The influence of the temperature on static and dynamic major B(H) loops is studied. Then, the Jiles-Atherton (JA) model and “flux tube” model are used, in order to reproduce the static and dynamic hysteresis loops for a NiFe (80/20) alloy. For each temperature, the six model parameters are optimized from measurements. Finally, these parameters are used in order to reproduce the behavior of a current transformer. The simulation results are compared with measurements and discussed. [ABSTRACT FROM PUBLISHER]

This paper presents the result of modeling the magnetic characteristics of ring-shaped cores made of Fe41.5Co41.5Nb3Cu1B13 alloy in both as-quenched and nanocrystalline state. For the modeling, the extended Jiles–Atherton model was used. Extension of Jiles–Atherton model is focused on taking into account the changes of parameter k caused by changes of the average energy required to break pinning site. Determination of model's parameters was made on the base of optimization process. This optimization covered both evolutionary strategies and simulated annealing. Finally, good agreement between experimental characteristics and the results of modeling was achieved. This agreement is confirmed by the high value of R^2 determination coefficient, which exceeds 99% for both as-quenched and annealed cores. As a result, it was confirmed that the presented method of modeling the magnetic characteristics of Fe41.5Co41.5Nb3Cu1B13 alloy in both as-quenched and nanocrystalline state is suitable for technical applications. [ABSTRACT FROM PUBLISHER]

Recent research results demonstrate that demagnetizing factors for various geometries can be precisely determined by employing 3-D electromagnetic field simulation. Using a technique developed by the authors, the demagnetizing factor resulting from the simulations match very well with experimental results for several series of samples with various geometries. The simulation technique developed by this project was also used for a spherical magnet using various field conditions, which has further proved the accuracy of this technique, whose results agree precisely with the theoretical analyses and mathematical calculation. Such simulation provides advantages over other methods including mathematical calculation and experimental measurement. Since any geometry with any dimensions can be simulated using the electromagnetic field simulation, the simulated results of “N” values can be stored in a data bank for any application using open-circuit measurements in the future. [ABSTRACT FROM AUTHOR]

A modified method, which combines chaos optimization method and simulated annealing algorithm, is proposed to calculate the Jiles-Atherton (J-A) model parameters. The new method is validated by comparing its computation results with measurement data. Then, the validated J-A model is used in numerical modeling of Epstein frame, and the numerical results are found to be in good agreement with measurement data. [ABSTRACT FROM PUBLISHER]

Problems involving intense pulsed magnetic fields in soft ferromagnetic materials require the solution of nonlinear partial differential equations with a field-dependent relative differential permeability that must represent the major magnetic properties of the material over an extremely wide range of magnetic fields. With the assumption that hysteresis can be neglected, a simple mathematical model with two exponential terms is described in which four constants can be used to model the magnetic properties of interest in a given problem. The model is constrained to match the initial value, the maximum value, and the saturation flux density. The analysis presented here shows that there are limitations and that not all values of the magnetic properties can be accommodated simultaneously. [ABSTRACT FROM PUBLISHER]