M. Pompei

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.

Magnetic losses in Si-Fe alloys for avionic applications

This paper presents an experimental analysis of the rotational power losses of the magnetic materials of transformers, motors and actuators used in avionic environment. A large frequency range is investigated using a suitable experimental test frame developed to measure the power losses for a circular magnetization. The results about different silicon iron alloys with different textures and thickness are considered and compared.

Performances prediction of inductive blocking devices for the mitigation of the lightning indirect effects

In this paper we propose a computational procedure to evaluate the performances of inductive blocking devices used for the mitigation of indirect lightning effects on electrical and electronic equipment in the avionic environment. The non linear behavior of the blocking devices are simulated using a finite difference scheme in time domain. Computations and experimental results are compared and discussed.

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.

Transmission of bits by means of non-uniform states in nanomagnets

Transmission of digital information is one of the most important aspects of modern technology. It can be accomplished along paths of nanomagnets, following the paradigm of the so-called nanomagnetic logic. When the clocking of nanomagnets is obtained by means of spin-Hall effect, interesting magnetization configurations are revealed by micromagnetic simulations. In this work, we show details of the non-uniform states that can be excited in a perpendicular nanomagnet for applications in nanomagnetic logic.

Phase locking of current-driven spin-Hall oscillators: A micromagnetic study

Magnetic materials, arranged in proper geometries, are used for the realization of microwave oscillators, like spin-transfer-torque and spin-Hall oscillators. In both cases, the synchronization of more oscillators allows the increase of the output power, that is needed for practical technological applications. In this paper, we show simulations of the synchronization of three spin-Hall oscillators, driven by a direct electrical current. The enlarged and coherent wavefront that is obtained can be used for on-chip communication between different devices.

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.