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Magnetics, IEEE Transactions on

Issue 3 • Date March 2009

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Displaying Results 1 - 25 of 238
  • [Front cover]

    Page(s): C1
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  • IEEE Transactions on Magnetics publication information

    Page(s): C2
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  • Table of contents

    Page(s): 925 - 939
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  • Message From the General Chairman and the Editorial Board Chairman

    Page(s): 940
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    Freely Available from IEEE
  • The 13th Biennial IEEE Conference on Electromagnetic Field Computation IEEE CEFC 2008 May 11–15, 2008 Athens, Greece

    Page(s): 941 - 943
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  • Parametric Models in Quasi-Static Electromagnetics

    Page(s): 944 - 947
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (253 KB) |  | HTML iconHTML  

    A procedure that speeds up parametric modelling is presented. With the help of manifolds and differential geometry it is possible to use a single mesh for problems corresponding to different parameter values. View full abstract»

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  • Optimal Convergence of the Fixed-Point Method for Nonlinear Eddy Current Problems

    Page(s): 948 - 951
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB) |  | HTML iconHTML  

    A method is presented for the optimal choice of the fixed-point reluctivity in nonlinear eddy current problems solved for steady-state in the frequency and the time domain. The optimal selection is shown to ensure a minimal contraction number for the fixed-point method. The proposed technique is compared to earlier approaches using a 2-D example. View full abstract»

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  • Analytical Computation of the Full Load Magnetic Losses in the Soft Magnetic Composite Stator of High-Speed Slotless Permanent Magnet Machines

    Page(s): 952 - 955
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    This paper presents an analytical model for predicting the stator full load magnetic losses in high-speed slotless permanent-magnet machines with surface-mounted magnets on the rotor and a stator core made of isotropic and conductive soft magnetic composite material (SMC). The losses are derived from the computation of the two-dimensional magnetic field distribution created by the rotor magnets, the currents in the stator windings and the eddy currents that circulate in the SMC stator core, according to the time and space harmonics. Both eddy currents and hysteresis losses are computed. The model is cross-validated by 2-D FE analysis in terms of magnetic field distribution and eddy currents losses. 3-D FE simulations are also carried out to quantify the end-effect on the stator no-load eddy current losses. The developed model is an efficient machine design tool, used here to quantify the variations of both the eddy currents and hysteresis losses under full load operation when the control angle is modified. View full abstract»

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  • Particle Swarm Design Optimization of ALA Rotor SynRM for Traction Applications

    Page(s): 956 - 959
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB) |  | HTML iconHTML  

    Particle swarm optimization (PSO) algorithm is applied to the design optimization problem of axially laminated anisotropic (ALA) rotor synchronous reluctance motor (SynRM) drive. The objective of the optimization is to maximize the developed torque while minimizing the torque ripple as well as the ohmic and core losses for traction applications. The number of flux paths, stator tooth width, and rotor flux path width define the 3-D search space for the optimization problem. An artificial intelligence modeling approach utilizing PSO and finite element-state space (FE-SS) models is used for the characterization and design optimization of a prototype ALA rotor SynRM drive for traction applications. View full abstract»

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  • Equivalent Circuit Approach for Evaluating Low-Frequency Magnetic Fields in the Presence of Non-Ferromagnetic Plates

    Page(s): 960 - 963
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (194 KB) |  | HTML iconHTML  

    An equivalent circuit approach was presented in this paper to evaluate low-frequency magnetic fields in the presence of non-ferromagnetic plates. Thin plates and conductors, as well as others, were modeled as interconnected and coupled circuit components. The eddy currents on the plates were then solved with a circuit analysis technique. The resultant magnetic field was calculated with the Biot-Savart law. The proposed approach was tested on two plate models, and the results were compared with those obtained from the boundary-element method and the laboratory experiment. A good agreement among these results was found. The proposed method is effective in handling multi-plate problems at low frequency. View full abstract»

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  • Reduced Magnetic Vector Potential Formulation in the Finite Element Analysis of Eddy Current Nondestructive Testing

    Page(s): 964 - 967
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB) |  | HTML iconHTML  

    The use of reduced magnetic vector potential (RMVP) in the three-dimensional finite element analysis of eddy current nondestructive testing (ECT) has demonstrated great flexibility, accuracy, and efficiency in case of coil excitation. This paper investigates the application of the RMVP in another class of eddy-current testing applications where the test sample of finite size is immersed in a uniform excitation field. The paper also shows that RMVP cannot be used in eddy-current testing problems having infinite current foil and infinite conducting plates. View full abstract»

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  • Comparison of Error Estimators in Eddy Current Testing

    Page(s): 968 - 971
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB) |  | HTML iconHTML  

    In this paper we present the comparison of error estimators using in 3-D magnetoharmonic FE model dedicated to eddy-current testing. The first error estimator is based on the nonverification of the behaviour law. This estimator is very accurate but requires the solution of both complementary formulations. The second estimator is based on an energetic approach using the Poynting vector in conductive regions and using the variation of the magnetic energy in nonconductive regions. Both estimators are tested within an adaptive meshing procedure and the results are compared with experimental results. View full abstract»

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  • Large-Scale Eddy-Current Analysis of Conductive Frame of Large-Capacity Inverter by Hybrid Finite Element-Boundary Element Method

    Page(s): 972 - 975
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (489 KB) |  | HTML iconHTML  

    This paper reports a large-scale eddy-current analysis of conductive frame of large-capacity inverter. The eddy-current loss obtained by the electromagnetic field analysis is used as a heat source for the thermal analysis. Then, the suitable configuration of the frame for the suppression of temperature increase is investigated and designed. The hybrid finite-element and boundary-element (FE-BE) method is very suitable for the analysis of a complicated-shaped frame because it does not require mesh division for a free space and can easily treat eddy current. For the reduction of large computational costs, the fast multipole method (FMM) is introduced. Furthermore, in order to improve the convergence characteristic of iterative methods for system matrix, we develop the application of the IDR(s) method to the minor iterative preconditioning technique (MIP) and evaluate the performance. Finally, some numerical results that demonstrate the effectiveness of the developed method are presented. View full abstract»

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  • Nonlinear Time-Domain Finite-Element Modeling of Thin Electromagnetic Shells

    Page(s): 976 - 979
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (197 KB) |  | HTML iconHTML  

    A nonlinear time-domain extension of the classical linear frequency-domain thin-shell approach is presented. The interface conditions are expressed in terms of the average magnetic flux density throughout the shell thickness and a number of higher order components. The method is elaborated in the frame of the magnetic vector potential formulation. The nonlinear system of algebraic equations is solved by means of the Newton-Raphson scheme. To validate the new formulation, we consider a magnetic plate placed above a double line carrying a sinusoidal current. Results are compared with those obtained with a fine finite-element model. View full abstract»

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  • Electro-Quasistatic High Voltage Field Simulations of Large Scale Insulator Structures Including 2-D Models for Nonlinear Field-Grading Material Layers

    Page(s): 980 - 983
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (475 KB) |  | HTML iconHTML  

    Resistive field-grading material is applied to nonceramic insulators. For the design of insulator structures, these resistive field-dependent and thus nonlinear material layers are considered as 2-D layers within 3-D transient finite element method (FEM) simulations of electro-quasistatic fields. The 2-D layer modeling approach is validated and compared to conventional 3-D layer modeling for various layer thicknesses. Numerical results for realistic structures are shown herein. View full abstract»

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  • A New Passive Maglev System Based on Eddy Current Stabilization

    Page(s): 984 - 987
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (414 KB) |  | HTML iconHTML  

    In this paper, a new passive maglev system is presented that is capable to levitate at a short distance from a dedicated guide. The magnetic suspension is assured by the repulsion of proper shaped permanent magnets that are present both on the fixed guide and on the moving suspended part. The presence of a conductive (aluminum) sheet that surrounds the magnets on the guide allows to overcome the intrinsic instability of the system when the suspended part is in relative motion with respect to the guide. The motional induced electric currents on the sheet interact with the magnets of the mover producing a stabilizing force. The detailed structure of the proposed system is described and the main results of the simulations by means of a hybrid electromagnetic FEM-MOM code coupled with the equation of motion of the rigid body are shown and commented. View full abstract»

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  • Fast Solution of a 3-D Integral Model for the Analysis of ITER Superconducting Coils

    Page(s): 988 - 991
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (470 KB) |  | HTML iconHTML  

    In this paper, we simulate the electromagnetic behavior of cable-in-conduit conductors (CICCs) and coils using a 3-D integral formulation of magneto-quasistatic Maxwell's equations, where the superconductors are represented by a power-law. The integral equation is numerically formulated using edge-elements and the nonlinear problem is discretized with a quasi-Newton algorithm. The solution of each iteration step is achieved with an iterative GMRES solver, which benefits from an singular value decomposition of the full matrix representing the integral operator. The model is applied to study the electromagnetic behavior of international thermonuclear experimental reactor (ITER) CICC and coils. View full abstract»

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  • Investigation of Algebraic Multigrid Method for Magnetic Field Analysis of an Electric Machine With a Laminated Core

    Page(s): 992 - 995
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1504 KB) |  | HTML iconHTML  

    In this paper, we describe the applicability of algebraic multigrid method (AMG method) as a fast solution for magnetic field analysis of an electric machine with a laminated core. In an experimental analysis, we have found that there are some cases where the calculation speed can be improved by using the AMG method for a fine mesh that models a laminated iron core exactly. Therefore we investigated the convergence characteristic of the standard incomplete Cholesky conjugate gradient method (standard ICCG method) and the conjugate gradient method preconditioned with AMG method (AMGCG method) for the simple and actual analysis models. The numerical results show that the AMGCG method provides fast solutions for laminated mesh models for which the standard ICCG method does not work well in many analysis cases. View full abstract»

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  • Electroquasistatic Analysis of the Gas Insulated Line for the ITER Neutral Beam Injector

    Page(s): 996 - 999
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (714 KB) |  | HTML iconHTML  

    In this paper, we formulate an electroquasistatic problem according to the discrete geometric approach. As an application, the transient behavior of the gas insulated transmission line for the ITER neutral beam injector system is analyzed. View full abstract»

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  • 3-D Electromagnetic Force Distribution in the End Region of Turbogenerator

    Page(s): 1000 - 1003
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (585 KB) |  | HTML iconHTML  

    The paper deals with detailed investigation of the electromagnetic forces in the end zone of turbine generator. The electromagnetic field is analyzed using 3-D FEM computation. The regions of interest are the stator and rotor end cores including the zone of the teeth and the end windings. The dynamic behavior of the local electromagnetic force densities is studied in accordance with the working mode. Two modes at the leading and at the lagging power factor are considered. Comparison between the ratio of the local electromechanical loads under considered modes and the relevant loads at the rated mode is discussed and appropriate conclusions are drawn. Calculations are implemented on a 200 MW turbine generator. View full abstract»

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  • Electrostatic Analysis of Moving Conductors Using a Perturbation Finite Element Method

    Page(s): 1004 - 1007
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (539 KB) |  | HTML iconHTML  

    This paper deals with the analysis of electrostatic problems involving moving devices by means of a perturbation finite element method. A reference problem without any moving parts is first solved and gives the source for a sequence of perturbation problems in subdomains restricted to the neighborhood of these parts. The source accounts for all the previous calculations for preceding positions what increases the efficiency of the simulations. This proposed approach also improves the computation accuracy and decreases the complexity of the analysis of moving conductors thanks to the use of independent and adaptively refined meshes. View full abstract»

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  • 3-D Eddy Current Computation in Carbon-Fiber Reinforced Composites

    Page(s): 1008 - 1011
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1172 KB) |  | HTML iconHTML  

    We propose a model for 3D eddy current computation in carbon-fiber reinforced composites, where only the active parts are discretized. The proposed method is based on the T- phi formulation. We use the finite difference method in the composite material, associated to a volume integral equation in the source region where a current source density is imposed. As a validation, numerical results are compared to analytical calculation, supported by a numerical example in eddy current nondestructive testing. View full abstract»

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  • Boundary Element Calculation of Eddy Currents in Cylindrical Structures Containing Cracks

    Page(s): 1012 - 1015
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB) |  | HTML iconHTML  

    Electromagnetic fields due to excitation coils in boreholes containing cracks have been calculated using a boundary element method formulated in terms of a scalar decomposition of the field. By using a Green's kernel that ensures continuity of the tangential electric and magnetic field at the cylindrical surface, it is only necessary to render the flaw region in a discrete form. The effect of an ideal crack, one with zero opening but acting as a perfect barrier to eddy currents, is here represented by a current dipole layer orientated normal to the crack surface. An integral equation determines the source density on the crack and a numerical solution is found using boundary elements. The coil impedance change due to the crack is then computed using an expression based on a reciprocity principle. View full abstract»

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  • Direct Modeling of Motional Eddy Currents in Highly Saturated Solid Conductors by the Magnetic Equivalent Circuit Method

    Page(s): 1016 - 1019
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB) |  | HTML iconHTML  

    Motional eddy currents are induced in conductors due to a localized vrarrtimesBrarr electric field. Direct modeling of this term by finite-element-based analysis may lead to nonphysical oscillations. In this paper, two modified magnetic equivalent circuit (MEC) methods to calculate motional eddy currents in highly saturated moving solid conductors are presented. The comparison between the results of the proposed methods with the finite-element method (FEM) proves high accuracy of the proposed methods in a wide velocity range for highly saturated solid conductors. The mesh sensitivity analysis shows the higher stability of the calculations of the proposed methods, compared with FEM, as no numerical oscillations occur. View full abstract»

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  • Nonlinear Eddy Current Analysis by BEM Utilizing Adaptive Equation Technique

    Page(s): 1020 - 1023
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (193 KB) |  | HTML iconHTML  

    Eddy currents induced in steel are analyzed by the boundary element method. As the periodic electromagnetic quantities in the steel are distorted due to the nonlinear magnetization property, they are expressed by a Fourier series, whose fundamental and harmonic waves are determined by solving the corresponding integral equations with the surface magnetic fields given as the boundary values. In this paper, we introduce a new combined integration scheme that enables efficient, volume-mesh-less treatment of the practical problems typically characterized by the geometrical singularities like edges and corners. Using this procedure, the internal and surface electromagnetic fields are obtained numerically one after another by applying an adaptive equation technique to obtain the boundary values. View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics publishes research in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology