Search results

1 – 10 of 131
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 1 April 1995

R. De Weerdt, K. Hameyer and R. Belmans

The calculation of the end winding leakage of a squirrel‐cage induction motor using a three‐dimensional finite element method is discussed. The end winding inductance is thought…

145

Abstract

The calculation of the end winding leakage of a squirrel‐cage induction motor using a three‐dimensional finite element method is discussed. The end winding inductance is thought to consist of a leakage, describing the flux linked with the end winding only, and a mutual part, describing the flux linked with both end winding and end ring. Both leakage and mutual inductance are found to vary for different load conditions.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 4
Type: Research Article
ISSN: 0332-1649

Access Restricted. View access options
Article
Publication date: 17 April 2023

Grzegorz Kostro, Michal Michna, Filip Kutt and Roland Ryndzionek

Calculating the stator end-winding leakage inductance, taking into account the rotor, is difficult due to the irregular shape of the end-winding. The end-winding leakage may…

111

Abstract

Purpose

Calculating the stator end-winding leakage inductance, taking into account the rotor, is difficult due to the irregular shape of the end-winding. The end-winding leakage may distribute at the end of the active part and the fringing flux of the air gap. The fringing flux belongs to the main flux but goes into the end-winding region. Then, not all the magnetic flux occurring in the end region is the end-winding leakage flux. The purpose of this paper was to find a method to accurately separate the leakage from the total flux, taking into account the rotor.

Design/methodology/approach

In this paper, two methods based on energy calculation are presented. Both methods require the assumption that the machine is symmetrical. The first method depends on the total leakage inductance and the machine’s active region length. The second method is based on the energy stored in the end region of the machine. In this case, removing the energy produced by the fringing flux of the air gap is necessary. The model should have a volume-closing fringing flux to remove the part of energy belonging to the end of the air gap.

Findings

The method presented in the paper does not require rotor removal. The values of the end-winding leakage inductance computed based on the proposed method were compared with values computed using the method with the removed rotor. The computations show that the proposed method is closest to the results from the method presented in the literature. Results obtained in the first method present that rotor influence on the value of end-winding leakage inductance exists. The model of the stator end-winding described in the paper is general. Therefore, the proposed methods are suitable for calculating the end-winding leakage inductance of other electric machines.

Originality/value

The method presented in the paper considers the rotor in end-winding leakage inductance calculation. It is not necessary to remove the rotor as in the similar method presented in the literature. The authors elaborated a parametric model with a volume-closing fringing flux to remove the part of energy belonging to the end of the air gap. The authors also elaborated their 3D model of the machine winding for calculations in Opera 3D.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 42 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 1 September 1999

H. De Gersem, D. Lahaye, S. Vandewalle and K. Hameyer

Finite element discretizations of low‐frequency, time‐harmonic magnetic problems lead to sparse, complex symmetric systems of linear equations. The question arises which Krylov…

2104

Abstract

Finite element discretizations of low‐frequency, time‐harmonic magnetic problems lead to sparse, complex symmetric systems of linear equations. The question arises which Krylov subspace methods are appropriate to solve such systems. The quasi minimal residual method combines a constant amount of work and storage per iteration step with a smooth convergence history. These advantages are obtained by building a quasi minimal residual approach on top of a Lanczos process to construct the search space. Solving the complex systems by transforming them to equivalent real ones of double dimension has to be avoided as such real systems have spectra that are less favourable for the convergence of Krylov‐based methods. Numerical experiments are performed on electromagnetic engineering problems to compare the quasi minimal residual method to the bi‐conjugate gradient method and the generalized minimal residual method.

Details

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

Keywords

Access Restricted. View access options
Article
Publication date: 1 June 2000

K. Wiak

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;…

929

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.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 1 June 2002

Herbert De Gersem and Kay Hameyer

A magnetic brake with a solid iron cylinder rotating at high speeds is considered. The rotor iron is both conductive and permeable. The magnetisation curve is non‐linear. Special…

374

Abstract

A magnetic brake with a solid iron cylinder rotating at high speeds is considered. The rotor iron is both conductive and permeable. The magnetisation curve is non‐linear. Special attention is paid to the correct integration of the angular velocity term. A Newton‐Raphson scheme dealing with the non‐linear material characteristics is applied. The numerical oscillations appearing in the finite element model at high velocities are overcome by an adaptive mesh refinement technique combined with the artificial diffusion upwind technique. End effects due to the finite length of the rotor are incorporated by an electric circuit coupling. Simulations are performed to study the influence of the saturation of the moving rotor upon the speed‐torque characteristic of the magnetic brake. It is remarkable that in the case of this solid rotor magnetic brake, the saturation of the rotor iron has a beneficial influence on the device performance.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 21 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 1 June 2001

Aldo Canova, Marco Ottella and Roger John Hill‐Cottingham

Presents the use of a 3D eddy current FE procedure for the analysis and design of two different induction machine structures: a radial and an axial machine. In the first case…

1215

Abstract

Presents the use of a 3D eddy current FE procedure for the analysis and design of two different induction machine structures: a radial and an axial machine. In the first case, attention is devoted to the simulation of locked rotor conditions and a linear 3D time harmonic eddy current FE analysis has been employed. The obtained results have been compared to 2D analysis and experimental data. The axial flux machine is analyzed under fixed speed conditions and a 3D time‐stepping and velocity eddy current problems are solved to evaluate machine performances. Different design configurations are analyzed in order to define the best solution.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 20 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 3 May 2013

István Király

The part of the stator leakage inductance whose quantity changes with the coil pitch is the slot leakage inductance. The purpose of this paper is to determine an analytical…

171

Abstract

Purpose

The part of the stator leakage inductance whose quantity changes with the coil pitch is the slot leakage inductance. The purpose of this paper is to determine an analytical expression which accounts for various slot shapes and the coil pitch change. This approach contrasts with the standard one, in which the same characteristics are inaccurately assumed for each slot shape. A further advantage of the proposed analytical expression is that it can also be used to model the slot leakage inductance for different phase numbers.

Design/methodology/approach

From the calculated coefficients of a slot by the Finite Element Method (FEM), the characteristics of the slot leakage coefficients are determined by an analytical expression. This helps one to study the connection between the slot shape types and the characteristics of slot leakage coefficients for different phase numbers.

Findings

The coefficients, which describe the change of slot leakage, are not the same for every slot type. These inaccuracies can result in deviation from the presented values in the classical literature.

Originality/value

By use of parameters, gained from the FEM calculation of a slot, the characteristics of the slot leakage coefficient can be determined as the function of winding pitch for different phase numbers by an analytical expression. Good accuracy of the analytical method is verified by the determination of the characteristics from the measurement of the two‐, three‐ and six‐phase windings and by the finite element calculations. Beside the speed of the process, it gives an overview about the connection between the slot shape and the coefficients.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 1 January 2012

Luigi Alberti, Nicola Bianchi and Samad Taghipour Boroujeni

To purpose of this paper is to introduce a procedure to compute the d‐ and q‐axis parameters of the induction motor.

234

Abstract

Purpose

To purpose of this paper is to introduce a procedure to compute the d‐ and q‐axis parameters of the induction motor.

Design/methodology/approach

A finite element procedure, based on the d‐ and q‐axis model of the induction motor is adopted.

Findings

Such a procedure is well suited to analyse IM with anisotropic rotor, where an intentionally created saliency is introduced in the rotor bar geometry, so as to detect the IM rotor position without sensor.

Originality/value

The proposed procedure allows one to evaluate the sensorless control capability of the IM. It will be useful for both analysis of the IM performance and design of the machine itself.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 15 November 2011

Erich Schmidt

The purpose of this paper is to discuss the state of the art of finite element analysis of electrical machines and transformers. Electrical machines and transformers are prime…

929

Abstract

Purpose

The purpose of this paper is to discuss the state of the art of finite element analysis of electrical machines and transformers. Electrical machines and transformers are prime examples of multi‐physical systems involving electromagnetics, thermal issues, fluid dynamics, structural mechanics as well as acoustic phenomena. An accurate operational performance with different electrical and mechanical load situations is more and more evaluated using various numerical analysis methods including the couplings between the various physical domains. Therefore, numerical analysis methods are increasingly utilized not only for the verification of contractual values of existing machines, but also for the initial design process and for the design optimization of new machines.

Design/methodology/approach

The finite element method is the most powerful numerical analysis method for such multi‐physical devices. Since optimizations with respect to the overall performance and also the total manufacturing costs will become more important, the utilization of coupled multi‐physical analyses is of growing interest. For the fast and powerful application of this numerical analysis method, special attention should be given to the requirements of these electromagnetic devices.

Findings

Various methods of coupling the different physical domains of multi‐field finite element analyses are described. Thereby, weakly coupled cascade algorithms can be used with most problems in the field of electrical machines and transformers. On the other hand, a prime objective is to derive comprehensive, multi‐physical simulation models which are easily incorporated into design tools used by engineering professionals.

Research limitations/implications

The development of robust and reliable computer‐aided tools for an optimal design of multi‐physical devices such electrical machines and transformers has to argue about the best possible coupling of various simulation methods. Special consideration shall be paid more and more to a treatment of uncertainties and tolerances by means of statistical and probabilistic approaches.

Originality/value

The paper discusses state of the art of finite element analyses of the mentioned devices. Various optimized methods of modelling and analysis concerning the repetitive structure of electrical machines for electromagnetic analyses are compared with their advantages and drawbacks. Further, various methods of coupling the different domains of multi‐field analyses in case of electrical machines and transformers are described.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 10 May 2011

Grzegorz Utrata and Andrzej Kaplon

The aim of the paper is to present the methodology of obtaining an approximate equivalent circuit composed of lumped parameters which describes an electromagnetic state of…

392

Abstract

Purpose

The aim of the paper is to present the methodology of obtaining an approximate equivalent circuit composed of lumped parameters which describes an electromagnetic state of induction machines (IMs) with solid secondary. Higher space harmonic field components are taken into account. The proposed method of machine model constructing is useful for solving electrodynamics states of solid secondary IMs, as well linear machines.

Design/methodology/approach

A determination of equivalent circuit parameters of a polyharmonic machine is divided into two steps. In the first step, frequency plots of the spectral inductances are derived – for each of the space harmonic components – from an electromagnetic field distribution calculated by means of the finite element method. In the second step, each of the spectral inductances are represented by the operational inductances which corresponds to the equivalent circuit composed of parallel connected the magnetizing inductance and branches consisting of resistance and inductance connected in series.

Findings

The proposed method allows the construction of the approximate equivalent circuit with lumped parameters which enables to solve electrodynamic states of solid secondary IMs, as well linear machines. The machine model has been derived with consideration of the higher space harmonic field components.

Research limitations/implications

Saturation effects of a magnetic circuit and an unbalance of phase currents have not been taken into account.

Originality/value

The paper shows the method of constructing a machine field‐circuit model. Lumped parameters of the model have been derived using frequency characteristics of the stator spectral inductance with consideration of the higher space harmonic field components.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

1 – 10 of 131
Per page
102050