S. Quondam Antonio

Surface Testing the Crystal Grain Orientation by Lag Angle Plots

In this paper, a technique based on contactless magnetic measurements is described to evaluate the orientation of the crystal grains in grain-oriented ferromagnetic materials. It is shown that both the orientation of the major easy axis, with respect to the rolling direction, and the angle of the out-of-plane axes with respect to the lamination plane, could be evaluated from non-invasive magnetic measurements by the analysis of the lag angle plots. The measured data have to be compared with the simulations of the single grain to estimate its orientation from the measured effects of the local in-plane magnetic anisotropy.

On the accuracy of vector magnetization measurements for FeSi steel sheets with different thicknesses and different grain sizes

In this work the vector magnetization measurements of silicon iron alloys FeSi have been developed. The magnetic field and the magnetization distribution on the sheets samples, with different thicknesses, have been analyzed respect to the probes sizes, the grains sizes and their relative positions. A discussion about the accuracy of the measurement procedures proposed is presented.

Some remarks about the magnetization processes in electrical steels via a micromagnetic approach

In this work the magnetic behaviour of Fe-Si alloys is investigated at microscopic scale in order to better understand the physical mechanisms which govern the magnetization phenomena in such materials. The analysis is carried out on thin Fe-Si films with uniaxial anisotropy by means of both a micromagnetic simulator and the Stoner-Wohlfarth model. The conditions under which the Stoner-Wohlfarth approximation can be operated in reproducing the magnetization processes of anisotropic steel films are discussed.

Implementation of the Single Hysteron Model in a Finite-Element Scheme

Electrical machines as transformers, motors, generators and actuators are in general simulated and designed using the Finite Element Method (FEM) [1–2].

Dynamic hysteresis modelling of soft magnetic materials for automotive applications

In the work presented the study about the most used dynamic hysteresis models for the ferromagnetic materials usually exploited in electrical vehicles is first focused. Among them, we propose an approach for the simulation of dynamic scalar magnetization processes based on the solution of the diffusion equation. This model will be used for the estimation and prediction of the magnetic losses in a sample of Non-Oriented (NO) iron-silicon steel with pulse width modulation (PWM) excitations, in the typical frequency range of interest for automotive. Comparative analysis with measurements using a Single Sheet Tester (SST) is reported.

On the effects of the average grain size in GO Fe-Si alloys: Magnetic measurements and simulations via the single hysteron model

In this paper the effects of the crystal grain dimensions upon the global magnetic behavior in Goss-textured magnetic materials is investigated. Three samples of Grain Oriented (GO) Fe-Si steels with different average grain size have been analyzed by means of both vector hysteresis measurements and simulations via the Single Hysteron Model.

Measuring magnetic losses in Si-Fe alloys with rotating polarization

The magnetic materials used for the manifacturing of electrical machines and for the industrial electronics applications have to be accurately characterized in a wide range of frequencies. In this paper we describe the experimental set up that we have recently developed in order to carry out magnetic measurements at high frequencies; in addition we present the magnetization processes measured, as well as the rotational losses, obtained in two different samples of electrical steels. The results can be very useful as data base for the identification and evaluation of dynamical models of vector hysteresis for the magnetic core design and optimization.

Three-phase inrush prediction and control in switching power supplies

In this paper the inrush current due to an arbitrary excitation of a three phase transformer after a fault is modeled in time domain. The approach proposed, although using several simplifying assumptions, seems promising in order to calculate the optimal time to close the circuit after a fault when solid state switching are used. This technique may be useful for many applications, among them the switching control of power supplies.

Magnetization processes of non oriented electrical steels: Vector hysteresis and energy losses measurements

This work presents measurements of the static magnetization processes of non oriented electrical steels usually used for the electrical machines. The experimental results obtained can be used as a benchmark for the identification procedures of phenomenological models used for the representation of the magnetic behavior of the electrical steels. The experimental set-up used and some results about scalar and vector magnetization processes and static hysteresis losses are presented in the paper.

Modeling of the magnetocrystalline cubic anisotropy in Fe-Si electrical steels

In this paper the modeling of the cubic anisotropy due to the crystal grain structure in Fe-Si steels has been developed by means of an analytical approach derived from the classical Stoner and Wohlfarth model. The magnetic behaviour of a circular Fe-Si particle that is assumed to be single crystal, is computed by both a micromagnetic simulator and the analytical model implemented.