C. Pertusa, S. Astier, Y. Lefevre and M. Lajoie‐Mazenc
An approach for electrical machines design by using a software which links the sizing procedure to the magnetic field computation is presented in this paper. After reviewing the…
Abstract
An approach for electrical machines design by using a software which links the sizing procedure to the magnetic field computation is presented in this paper. After reviewing the principles of an electrical machine general design, the process of the development and the use of a special link between the dimensions data and the magnetic field computation is described. The whole solution procedure is conducted automatically. Any change on the machine dimensions can be made and the sequence of the CAD tasks can be prepared and run automatically without any user intervention. The whole procedure is applied to a comparative study of different structures of permanent magnets synchronous motors.
N. Sadowski, Y. Lefevre, M. Lajoie‐Mazenc and J.P.A. Bastos
The paper describes the analysis and the calculation of transient response of a voltage fed electromagnet. This calculation is based on the simultaneous solution of the magnetic…
Abstract
The paper describes the analysis and the calculation of transient response of a voltage fed electromagnet. This calculation is based on the simultaneous solution of the magnetic field equations and the electrical circuit equations. In the modelling of the magnetic fields, eddy currents in solid conductive parts and saturation of magnetic parts are taken into account. This modelling uses Finite Element Method for the calculation of magnetic fields and forces with special quadrilateral elements. Experimental and simulation results for an axisymmetrical electromagnet are presented and compared.
Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines;…
Abstract
Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.
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Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community…
Abstract
Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.
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Abstract
A model coupling magnetic and electric equations is developed in this paper. The unknowns in this model are the magnetic vector potential and the mesh currents. The nature of the resulting matrix system does not permit the use of the classical Cholesky algorithm. A new decomposition, based on the Cholesky method, is introduced to solve it. To illustrate the efficiency of the method, an example of an iron core coil is modelled. Both calculation time and memory storage are compared with classical methods.
G.B. Kumbhar, S.V. Kulkarni, R. Escarela‐Perez and E. Campero‐Littlewood
This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with selective…
Abstract
Purpose
This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with selective bibliography and practical examples, to help postgraduate students, researchers and designers working in design or analysis of electrical machinery.
Design/methodology/approach
This paper reviews the recent trends in coupled field formulations. The use of these formulations for designing and non‐destructive testing of electrical machinery is described, followed by their classifications, solutions and applications. Their advantages and shortcomings are discussed.
Findings
The paper gives an overview of research, development and applications of coupled field formulations for electrical machinery based on more than 160 references. All landmark papers are classified. Practical engineering case studies are given which illustrate wide applicability of coupled field formulations.
Research limitations/implications
Problems which continue to pose challenges to researchers are enumerated and the advantages of using the coupled‐field formulation are pointed out.
Practical implications
This paper gives a detailed description of the application of the coupled field formulation method to the analysis of problems that are present in different electrical machines. Examples of analysis of generators and transformers with this formulation are presented. The application examples give guidelines for its use in other analyses.
Originality/value
The coupled‐field formulation is used in the analysis of rotational machines and transformers where reference data are available and comparisons with other methods are performed and the advantages are justified. This paper serves as a guide for the ongoing research on coupled problems in electrical machinery.
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Andrzej Demenko and Kay Hameyer
The purpose of this paper is to develop and systemize the 3D finite element (FE) description of electromagnetic field in electrical machines.
Abstract
Purpose
The purpose of this paper is to develop and systemize the 3D finite element (FE) description of electromagnetic field in electrical machines.
Design/methodology/approach
3D FE models of electrical machines are considered. The model consists of FE equations for the magnetic field, equations describing eddy currents and equations, which describe the currents in the machine windings. The FE equations are further coupled by the electromagnetic torque to the differential equation of motion. In the presented field‐circuit model, the flux linkages with the windings are expressed by two components. Attention is paid to the description of machine winding. Both scalar and vector potential formulations are analysed. The FE equations are derived by using the notation of circuit theory. The methods of movement simulation and torque calculation in FE models are discussed.
Findings
Proposed circuit description of electromagnetic field in electrical machines conforms to the applied method of electric and magnetic circuit analysis. The advantage of the presented description is that the equations of field model can be easy associated with the other equations of the electric drive system.
Originality/value
The applied analogies between the FE formulation and the equivalent magnetic and electric network models help formulate efficient field models of electrical machines. The developed models after coupling to the models of supply and control system can be successfully used in the analysis and design electric drives.
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Abstract
This paper presents a model based on the 2D finite element method (FEM) which can be used to study a self‐excited induction generator in unbalanced modes. In the proposed model, we take into account the magnetic non linearity of the iron by introducing a B(H) curve which is identified experimentally from magnetic materials. On the other hand, effects such as end windings and the short circuit ring are also taken into account using analytical expressions. The coupling between electrical circuit and FE equations is introduced. After validating the model in steady and transient modes, we will discuss the choice of the different capacitances and give simulated results of a specific unbalanced case.
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The purpose of this paper is to model one of the unsolved problems of magnetism, the reversal of hysteresis loops, in an analytical way. The mathematical models, describing the…
Abstract
Purpose
The purpose of this paper is to model one of the unsolved problems of magnetism, the reversal of hysteresis loops, in an analytical way. The mathematical models, describing the multiphase steel used in engineering practice, without any exception, are unsuited to provide a way to reverse the hysteretic process. In this paper, a proposal is put forward to model it by using analytical expressions, applying the reversal of the Langevin function. This model works with a high accuracy, giving useful answers to a long unsolved magnetic problem, the lack of reversibility of the hysteresis loop. The use of the proposal is shown by applying the reversal of Langevin function to a sinusoidal and a triangular waveform, the two most frequently used waveforms in research, test and industrial applications. Schematic representations are given for the wave reconstruction by using the proposed method.
Design/methodology/approach
The unsolved reversibility of the hysteresis loop is approached by a simple analytical formula, providing close approximation for most applications.
Findings
The proposed solution, applying the reversal of Langevin function, to the problem provides a good practical solution.
Research limitations/implications
The simple analytical formula has been applied to a number of loops of widely different shapes and sizes with excellent results.
Practical implications
The proposed solution provides a missing mathematical tool to an unsolved problem for practical applications.
Social implications
The solution proposed will reduce the work required and provide replacement for expensive complex test instrumentation.
Originality/value
To the best of the authors’ knowledge, this approach used in this study is the first successful approach in this field, irrespective of the required waveform, and is completely independent of the model used by the user.
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Brijesh Upadhaya, Floran Martin, Paavo Rasilo, Paul Handgruber, Anouar Belahcen and Antero Arkkio
Non-oriented electrical steel presents anisotropic behaviour. Modelling such anisotropic behaviour has become a necessity for accurate design of electrical machines. The main aim…
Abstract
Purpose
Non-oriented electrical steel presents anisotropic behaviour. Modelling such anisotropic behaviour has become a necessity for accurate design of electrical machines. The main aim of this study is to model the magnetic anisotropy in the non-oriented electrical steel sheet of grade M400-50A using a phenomenological hysteresis model.
Design/methodology/approach
The well-known phenomenological vector Jiles–Atherton hysteresis model is modified to correctly model the typical anisotropic behaviour of the non-oriented electrical steel sheet, which is not described correctly by the original vector Jiles–Atherton model. The modification to the vector model is implemented through the anhysteretic magnetization. Instead of the commonly used classical Langevin function, the authors introduced 2D bi-cubic spline to represent the anhysteretic magnetization for modelling the magnetic anisotropy.
Findings
The proposed model is found to yield good agreement with the measurement data. Comparisons are done between the original vector model and the proposed model. Another comparison is also made between the results obtained considering two different modifications to the anhysteretic magnetization.
Originality/value
The paper presents an original method to model the anhysteretic magnetization based on projections of the anhysteretic magnetization in the principal axis, and apply such modification to the vector Jiles–Atherton model to account for the magnetic anisotropy. The replacement of the classical Langevin function with the spline resulted in better fitting. The proposed model could be used in the numerical analysis of magnetic field in an electrical application.