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Article
Publication date: 1 February 1982

I. MAYERGOYZ

New iteration methods for the calculation of steady magnetic fields in saturable media are presented. These methods converge for any choice of initial approximation, that…

Abstract

New iteration methods for the calculation of steady magnetic fields in saturable media are presented. These methods converge for any choice of initial approximation, that is they possess global convergence. The convergence conditions and the estimates of convergence rate of these methods are expressed in terms of the physical properties of ferromagnetic media. Each of the proposed methods is deliberately adapted to specific but typical saturation conditions. All these methods together cover the broad area of diverse saturation conditions encountered in practice. The construction and justification of these iteration methods are based on the physical concept of secondary sources and on some mathematical ideas and results arising in the overlapping area of mathematical physics and functional analysis.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 1 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 8 August 2019

Michael Nierla, Michael Loeffler, Manfred Kaltenbacher and Stefan Johann Rupitsch

The numerical computation of magnetization processes in moving and rotating assemblies requires the usage of vector hysteresis models. A commonly used model is the…

Abstract

Purpose

The numerical computation of magnetization processes in moving and rotating assemblies requires the usage of vector hysteresis models. A commonly used model is the so-called Mayergoyz vector Preisach model, which applies the scalar Preisach model into multiple angles of the halfspace. The usage of several scalar models, which are optionally weighted differently, enables the description of isotropic as well as anisotropic materials. The flexibility is achieved, however, at the cost of multiple scalar model evaluations. For solely isotropic materials, two vector Preisach models, based on an extra rotational operator, might offer a lightweight alternative in terms of evaluation cost. The study aims at comparing the three mentioned models with respect to computational efficiency and practical applicability.

Design/methodology/approach

The three mentioned vector Preisach models are compared with respect to their computational costs and their representation of magnetic polarization curves measured by a vector vibrating sample magnetometer.

Findings

The results prove the applicability of all three models to practical scenarios and show the higher efficiency of the vector models based on rotational operators in terms of computational time.

Originality/value

Although the two vector Preisach models, based on an extra rotational operator, have been proposed in 2012 and 2015, their practical application and inversion has not been tested yet. This paper not only shows the usability of these particular vector Preisach models but also proves the efficiency of a special stageless evaluation approach that was proposed in a former contribution.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 38 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 February 1987

Michael GAITAN and Isaak D. MAYERGOYZ

The development of a numerical implementation of the small signal response of the MOS (Metal‐Oxide‐Silicon) capacitor using time perturbation analysis is discussed. The…

Abstract

The development of a numerical implementation of the small signal response of the MOS (Metal‐Oxide‐Silicon) capacitor using time perturbation analysis is discussed. The effects of nonconstant doping profiles and interface and bulk traps are included. The model uses Fermi‐Dirac statistics to describe the occupancy of the interface and bulk traps. The oxide region is considered to have no mobile carriers and any fixed oxide charge distribution is modeled as a charge sheet at the Si‐SiO2 interface. This technique can be used to find the small signal response of the device from the static solution.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 6 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 19 June 2007

Giovanni Miano, Fabio Villone and Walter Zamboni

To study optical resonances in metallic nanoparticles.

Abstract

Purpose

To study optical resonances in metallic nanoparticles.

Design/methodology/approach

The metallic nanoparticle is modeled as a dielectric body dispersive in frequency with assigned dielectric constant. The electric field is expressed as function of the charge distribution through an integral formulation. By imposing the boundary conditions on the nanoparticle surface, the equations for the induced charge in the nanoparticle is obtained. The numerical solution of such equations allows to treat arbitrary geometries and to estimate the effects of deviations from ideality on the resonance values.

Findings

Plasmon resonances in metallic nanoparticles can be safely studied with an electro‐quasistatic approximation. The resonance frequencies depend greatly on the details of the geometry of the nanoparticles.

Research limitations/implications

The free‐space wavelength is supposed to be much greater than the largest characteristic dimension of the nanoparticles. Consequently, a electro‐quasistatic model is used to evaluate the distribution of the charges induced in the metallic nanoparticle.

Originality/value

Two methods are presented for the evaluation of the resonance frequencies starting from the numerical solution for a given geometry.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 8 March 2011

Miklós Kuczmann

The purpose of this paper is to present a Preisach model to simulate the vector hysteresis properties of ferromagnetic materials.

Abstract

Purpose

The purpose of this paper is to present a Preisach model to simulate the vector hysteresis properties of ferromagnetic materials.

Design/methodology/approach

The vector behavior has been studied at low frequency applying a single‐sheet tester with a round‐shaped specimen, and the locus of the magnetic flux density vector has been controlled by a digital measurement system. An inverse vector Preisach hysteresis model has been developed and identified by using the measured data.

Findings

Finally, the inverse model has been inserted into a finite element procedure through the combination of the fixed point technique and the reduced magnetic scalar potential formulation. The developed single‐sheet tester measurement system has been simulated. The applicability of the realized measurement system as well as the developed model has been proven by comparing measured and simulated results.

Originality/value

The identification technique is original, based on a previous work of the author.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 28 October 2014

Miklós Kuczmann

The purpose of this paper is to develop a viscous-type frequency dependent scalar Preisach hysteresis model and to identify the model using measured data and nonlinear…

Abstract

Purpose

The purpose of this paper is to develop a viscous-type frequency dependent scalar Preisach hysteresis model and to identify the model using measured data and nonlinear numerical field analysis. The hysteresis model must be fast and well applicable in electromagnetic field simulations.

Design/methodology/approach

Iron parts of electrical machines are made of non-oriented isotropic ferromagnetic materials. The finite element method (FEM) is usually applied in the numerical field analysis and design of this equipment. The scalar Preisach hysteresis model has been implemented for the simulation of static and dynamic magnetic effects inside the ferromagnetic parts of different electrical equipment.

Findings

The comparison between measured and simulated data using a toroidal core shows a good agreement. A modified nonlinear version of TEAM Problem No. 30.a is also shown to test the hysteresis model in the FEM procedure.

Originality/value

The dynamic model is an extension of the static one; an extra magnetic field intensity term is added to the output of the static inverse model. This is a viscosity-type dynamic model. The fixed-point method with stable scheme has been realized to take frequency dependent anomalous losses into account in FEM. This scheme can be used efficiently in the frame of any potential formulations of Maxwell's equations.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 January 1993

Bruno Amable, Jérôme Henry, Frédéric Lordon and Richard Topol

Hysteresis is one of the main concepts used in Layard, Nickell andJackman′s book, Unemployment: Macroeconomic Performance and theLabour Market. Attempts to clarify the…

Abstract

Hysteresis is one of the main concepts used in Layard, Nickell and Jackman′s book, Unemployment: Macroeconomic Performance and the Labour Market. Attempts to clarify the concept of hysteresis, from its formal representation to its empirical applications. Emphasizes the idea that hysteresis refers back to a given set of formal properties, independently of the phenomenologies within which it is liable to be encountered. In economics, the fields concerned may indeed vary a lot (labour market, foreign trade, etc.). By highlighting all the formal properties of hysteresis, shows how the assimilation of phenomena characterized by a zero eigenvalue for linear systems (or unit‐root systems for discrete‐time processes) is wrong and, moreover, how the imprecise use of the concepts can lead to the particular constraints affecting unit‐root econometrics being overlooked.

Details

Journal of Economic Studies, vol. 20 no. 1/2
Type: Research Article
ISSN: 0144-3585

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Article
Publication date: 1 September 1999

Carlo Ragusa and Maurizio Repetto

The implementation of a vector Preisach model for the modelling of anisotropic hysteretic soft magnetic materials is outlined. Some comparisons with measurements on…

Abstract

The implementation of a vector Preisach model for the modelling of anisotropic hysteretic soft magnetic materials is outlined. Some comparisons with measurements on alternate and rotational magnetic field excitations are shown. The hysteresis model is inserted inside a two‐dimensional finite element solver formulated in terms of magnetic vector potential and nonlinear solution is handled by means of the fixed point method with H‐scheme. Results obtained on a two‐dimensional geometry are described and discussed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 18 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 19 June 2007

G. Miano, G. Rubinacci and A. Tamburrino

The paper is focused on the numerical modelling of the interaction between electromagnetic fields and metallic nanoparticle.

Abstract

Purpose

The paper is focused on the numerical modelling of the interaction between electromagnetic fields and metallic nanoparticle.

Design/methodology/approach

A full‐wave solution of the field problem is modelled in terms of an integral equation where the unknown is the displacement current. For treating nanoparticles having sizes smaller than the relevant wavelength, particular care is devoted to the choice of the discrete representation of the unknown in view of the condition number of the resulting linear system of equations.

Findings

A critical analysis of the issues to be considered for developing a proper numerical model of the problem is presented. Specifically, it is shown that the electric field inside the nanoparticle is not purely irrotational, as usually assumed in the widespread models based on the electrostatic approximation.

Originality/value

The proposed formulation is applied for the first time to the problem of evaluating the interaction between electromagnetic fields and metallic nanoparticle.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 5 July 2013

Martin Petrun, Krzysztof Chwastek and Drago Dolinar

The aim of the paper is to provide a simple and reliable hysteresis model for prediction of magnetization curves of a resistance spot welding transformer (RSWT) core…

Abstract

Purpose

The aim of the paper is to provide a simple and reliable hysteresis model for prediction of magnetization curves of a resistance spot welding transformer (RSWT) core, operating in a wide range of flux densities and excitation frequencies.

Design/methodology/approach

The hysteresis model considered in the paper is the T(x) description advanced by J. Takács. Three options to extend the model to the dynamic magnetization conditions are considered. The excitation conditions differ from those prescribed by international standards.

Findings

The quasi‐static Takács model combined with a fractional viscosity equation similar to that proposed by S.E. Zirka outperforms other considered options. The effect of eddy currents may be considered as a disturbance factor to the frequency‐independent quasi‐static hysteresis loop.

Research limitations/implications

The combined approach yields in most cases a satisfactory agreement between theory and experiment. For highest frequency considered in the paper (1 kHz) excessive “heels” were observed in the modelled loops. This artifact may be reduced by the introduction of a more complicated relationship for the viscous term. Future work shall be devoted to this issue.

Practical implications

The combined Takács‐Zirka model is a useful tool for prediction of magnetization curves of a RSWT core in a wide range of flux densities and excitation frequencies.

Originality/value

The usefulness of the Takács description has been verified in a practical application. The model is able to predict magnetization curves under non‐standard excitation conditions.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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