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Magnetics, IEEE Transactions on

Issue 2 • Date March 1997

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Displaying Results 1 - 25 of 266
  • IEEE Transactions on Magnetics, March 1997 Part II

    Publication Year: 1997 , Page(s): i - ix
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    First Page of the Article
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  • A finite element formulation for eddy current carrying ferromagnetic thin sheets

    Publication Year: 1997 , Page(s): 1173 - 1178
    Cited by:  Papers (13)
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    A finite element formulation for ferromagnetic thin sheets carrying time-harmonic eddy currents is presented. The static field outside the sheets is described by a magnetic scalar potential on one side of the sheet and by a magnetic vector potential on the other side. Special interface conditions resulting in a symmetric finite element system matrix are developed to take account of the sheet. A simple example is presented to demonstrate the efficiency of the method. View full abstract»

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  • Finite element analysis of multiport filters using perfectly matched layers

    Publication Year: 1997 , Page(s): 1480 - 1483
    Cited by:  Papers (7)
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    A 3D edge finite element analysis is presented to calculate the resonance frequencies and quality factors of inhomogeneously loaded cavity resonators (filters) terminated by waveguides (ports). The matching of the ports is modeled by perfectly matched layers (PML). The selection of the PML parameters is discussed. A complex nonlinear eigenvalue problem is obtained which is solved by a special solver with the sparsity of the matrices fully utilized. An approximation is applied to reconstruct the frequency response of the scattering parameters from the field calculated at the resonance frequencies. View full abstract»

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  • Conference Author Index

    Publication Year: 1997 , Page(s): 2219 - 2222
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    Freely Available from IEEE
  • 3-D time-periodic finite element analysis of magnetic field in non-oriented materials taking into account hysteresis characteristics

    Publication Year: 1997 , Page(s): 1584 - 1587
    Cited by:  Papers (3)
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    Problems in analyzing 3-D stationary nonlinear magnetic field in non-oriented material taking into account hysteresis characteristics and eddy current, such as finite element formulation and convergence of nonlinear iteration, are discussed View full abstract»

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  • Wavelet solution of the inverse parameter problems

    Publication Year: 1997 , Page(s): 1962 - 1965
    Cited by:  Papers (2)
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    Previously, we have proposed a method of solving inverse problems, and successfully applied the method to biomagnetic fields as well as the nondestructive testing in metallic materials. In the present article, we propose a novel inverse approach for the parameter determination problems employing wavelet analysis. A simple example of parameter determination demonstrates the validity of our wavelet approach View full abstract»

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  • Numerical analysis of 4-arm Archimedian printed spiral antenna

    Publication Year: 1997 , Page(s): 1512 - 1515
    Cited by:  Papers (3)
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    A numerical technique is applied to find the current distribution on 4-arm Archimedian spiral antennas printed on a dielectric substrate. The integral equation for the current distribution is formulated, which is solved by using the parametric B-spline finite element method. Numerical results of the current distribution for different dielectric permittivities are presented, showing that the current distribution on the 4-arm Archimedian printed spiral antenna has a standing-wave nature View full abstract»

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  • Triangular element refinement in automatic adaptive mesh generation

    Publication Year: 1997 , Page(s): 1740 - 1743
    Cited by:  Papers (4)
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    Given the nature of many magnetic field problems however, where very narrow material regions and curved boundaries exist, the angle condition is often difficult to satisfy using the standard centroid refinement approach. A new refinement strategy is proposed for use in an adaptive procedure. The method developed places new nodes in regions of high solution error such that the benefit of the Delaunay re-triangulation algorithm is fully realised. Results show that the improved mesh geometry obtained with this method compared with the conventional centroid approach produces a more efficient mesh, where less nodes are needed to obtain the same solution accuracy. New algorithms with the purpose of removing thin elements and obtaining a gradual transition in node density in the mesh after each refinement step are also described View full abstract»

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  • Optimization algorithms for magnetics and their parallelizability

    Publication Year: 1997 , Page(s): 1966 - 1969
    Cited by:  Papers (2)
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    Parallelization of optimization routines is now increasingly resorted to, because of the heavy computation associated with the optimization of electromagnetic products in the process of their design. This paper evaluated the possibilities for parallelization in electromagnetic product design. The several optimization algorithms available are evaluated for their parallelizability. It is further shown that, given the present limits of technology in relation to the number of processors available on shared memory computers of parallel architecture, parallelization in electromagnetic optimization is not necessarily worth attempting at present. Thus, works of this nature, are of necessity, for the future, in readiness for that day when a new generation of parallel computer is available to us View full abstract»

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  • Optimal pole shape design for the reduction of cogging torque of brushless DC motor using evolution strategy

    Publication Year: 1997 , Page(s): 1908 - 1911
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    This paper describes a design procedure that reduces the cogging torque of brushless DC motors. This paper proposes that a predefined slot shape on the pole surface reduces the cogging torque. Standard finite elements are used for field calculation, Maxwell stress tensor for torque calculation and an evolution strategy for the optimal design process to determine the slot size. Verified experiment shows that the proposed algorithm reduces the level of mechanical vibration and noise substantially View full abstract»

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  • Edge element analysis of complex configurations in presence of shields

    Publication Year: 1997 , Page(s): 1548 - 1551
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    A finite element (FE) approach is presented to analyze the electromagnetic field in free space considering the field penetration through shields in complex configurations. The shield region is eliminated from the FE domain and substituted by an equivalent surface, where constraint conditions avoid the continuity of the tangential fields. The constraint relationships between the tangential fields on both facets of the surface are obtained by the shielding theory. The implementation of the proposed method is presented to solve the electric field wave equation using edge elements View full abstract»

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  • Modelling HTc superconductors for AC power loss estimation

    Publication Year: 1997 , Page(s): 1568 - 1571
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    AC losses in high-temperature superconductors are modelled as a highly non-linear diffusion process. Two empirical expressions for modelling effective resistivity of the conductor are used. Formulations in terms of both H and E are presented and it is argued, using dimensional analysis, that working with E is numerically more efficient. Typical results calculated using a finite-difference scheme are shown View full abstract»

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  • Eddy current analysis on thin conducting plate by an integral equation method using edge elements

    Publication Year: 1997 , Page(s): 1346 - 1349
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    Eddy current distributions on a thin conducting plate are solved by an integral equation method using edge elements. The normal component of eddy current density across the edge of triangular element is chosen as the unknown variable. In this paper, the authors investigate how to define the set of unknowns. The tree and co-tree of surface eddy current paths are introduced. The unknown surface current densities are defined on the paths of the co-tree and the zero divergence condition is applied to those of the tree. The proposed method is applied to a simple computation model in order to verify the applicability of the method View full abstract»

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  • Force calculation based on a local solution of Laplace's equation

    Publication Year: 1997 , Page(s): 1216 - 1218
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    The finite element method in two dimensions is a common technique to analyse electromagnetic devices. The co-ordinates is given as a series of circular harmonics of Maxwell stress method to calculate forces has an important role in this analysis. To obtain an acceptable accuracy of local field values, higher order elements are required yielding an increased computation time. A local solution of Laplace's equation with the finite element solution as boundary conditions, promises a higher accuracy than the conventional method. The combination with lower order elements gives a good trade-off between accuracy and computation time. Two different methods are compared in the analysis of two applications. A typical example of a rotating machine with a small air gap, a squirrel cage induction machine, is discussed View full abstract»

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  • Calculation of superconducting magnetic bearings using a commercial FE-program (ANSYS)

    Publication Year: 1997 , Page(s): 1572 - 1575
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    A new ANSYS-element, which includes three different macroscopic models for high-temperature superconductors, is presented. The element formulation is verified by comparing experimental results with calculated results. An existing flywheel system is calculated and first suggestions for its geometric optimization are made View full abstract»

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  • A coupling model for analysing dynamical behaviours of an electromagnetic forming system

    Publication Year: 1997 , Page(s): 1638 - 1641
    Cited by:  Papers (13)
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    A coupling model for analysing dynamical behaviour of an electromagnetic forming system consisting of the expansion of a metallic cylinder by means of an internal solenoidal coil is presented. The two equations governing transient magnetic field and dynamic plastic deformation are solved simultaneously by using finite element and Runge-Kutta methods respectively. The electromotive force due to the deformation is considered. Owing to the fact that the mechanical configuration changes during motion, a suitable technique to avoid introduction of a speed term as well as the remesh generation at each time step is proposed. Eddy currents, magnetic force density, radial displacement and velocity of the cylinder are calculated. The numerical results are in good agreement with measurements View full abstract»

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  • Consideration of magnetization and detection on magnetic rotary encoder using finite element method

    Publication Year: 1997 , Page(s): 2159 - 2162
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    This article shows the results of a feasibility study of a high resolution magnetic rotary encoder. The magnetization and the detection processes of a magnetic rotary encoder were simulated using the finite element method. In addition, experimental considerations have been given to the numerical effect of the parameters on a magneto-resistive (MR) output by a method of double interpolation. The optimum condition of a Z phase (i.e., original point of the rotation) signal obtained for the magneto-resistive output was a magnetization gap 0 μm and a magnetization current of 400 mA (i.e., the magnetized state for saturation of the medium). It was analytically determined that an increase in magnetization current or a detection gap reduction saturated the magneto-resistive output voltage. The magneto-resistive output obtained using FEM showed good numerical agreement with experimental results, given conditions when the magnetization current was 200 mA or less. It was an advantage therefore, in the case of the minimum MR element being used with a double interpolation method, to achieve a wider usable detection gap range View full abstract»

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  • A boundary integral equation method for the calculation of the effective permittivity of periodic composites

    Publication Year: 1997 , Page(s): 1580 - 1583
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    We present a numerical method based upon the resolution of boundary integral equations for the calculation of the effective permittivity of a lossless composite structure consisting of a two component mixture, each with its own dielectric and shape characteristics. The topological arrangements considered are periodic lattices of inhomogeneities. Our numerical simulations are compared to the effective medium approach and with results of previous works View full abstract»

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  • Development of EWS aided graphical facilities for computational electromagnetism

    Publication Year: 1997 , Page(s): 1978 - 1981
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    The engineering work station (EWS) and the personal computer (PC) have been applied to various electromagnetic problems in computational electromagnetism, whose practical calculations have been conventionally executed by mainframe computers. Although the practical programs coded under the mainframe computer system may be readily migrated to those on the EWS and the PC, the graphical output facilities are not always available in all the computational environments. The paper proposes the license-royalty free and portable graphical utilities, which comprise the CALCOMP compatible plotter control library PSP that generates the HP-GL codes, the gl2ps that converts the HP-GL data to the Postscript language, and the xngraph that can depict the schematic results using the raw numeric data View full abstract»

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  • A virtual electromagnetic laboratory for the classroom and the WWW

    Publication Year: 1997 , Page(s): 1990 - 1993
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    A virtual laboratory for the classroom as well as for distance education on World Wide Web is presented making use of the various FEM software packages for the numerical calculation of electromagnetic field problems developed at IGTE. For creating interactive educational examples, the HTML-format specification was chosen. The interaction between the HTML document and the FEM software is performed by the widespread Tool Command Language (TCL) View full abstract»

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  • Optimal design of transient eddy current systems driven by voltage source

    Publication Year: 1997 , Page(s): 1624 - 1629
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    The structure and the characteristics of an optimal design procedure of electromagnetic devices are examined and the three different approaches to design sensitivity derivation are reviewed. For the shape design problems of the transient eddy current systems driven by voltage sources, the design sensitivity is derived in an explicit form to the design variables using the finite element algebraic system equation and the adjoint variable method. The original state variable equation is an initial value problem, but the adjoint variable equation is derived as a terminal value problem. Both equations are solved using a time-stepping finite element method. As a numerical example, the coil-positioning problem of an induction heating system is tested and the proposed algorithm is validated View full abstract»

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  • 3D eddy currents modelling by means of a particular reduced scalar potential technique

    Publication Year: 1997 , Page(s): 1350 - 1353
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    The paper uses a particular reduced scalar potential technique enabling 3D eddy currents modelling in cases where the currents are developed in well defined paths (such as shading rings, cages etc.). This method involves a scalar potential in the whole solution domain and a single component vector quantity in the conducting parts. Experimental verification is performed by comparing computed and measured forces, developed in a contactor consisting of an E-shape electromagnet with shading rings View full abstract»

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  • Edge-nodal coupled method for computing 3D eddy current problems

    Publication Year: 1997 , Page(s): 1378 - 1381
    Cited by:  Papers (1)
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    An edge-nodal coupled method, which uses edge elements in the eddy current region and nodal finite elements in the non-eddy current region to discretize H model, is presented for solving 3D eddy current problems. The mathematical models are divided into the “strong” form and the “weak” form model. Special treatment on the interface is presented. The test results are shown for the validity of the proposed algorithm View full abstract»

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  • A greedy genetic algorithm for continuous variables electromagnetic optimization problems

    Publication Year: 1997 , Page(s): 1900 - 1903
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    A greedy genetic algorithm for continuous variables electromagnetic optimization problems is presented. The presented algorithm is characterized by the use of a nonlinear simplex method as a principal optimizer, and of a greedy genetic algorithm to explore the search space, realizing a balance between diversity and a bias toward fitter individuals. The resulting algorithm merges the efficiency typical of calculus-based search with the robustness typical of random methods. A detailed comparison of the performance obtained implementing several strategies is presented, using an electromagnetic design test problem View full abstract»

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  • The inverse problem methodology for the measurement of the permeability of the ferromagnetic materials

    Publication Year: 1997 , Page(s): 2139 - 2142
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    The inverse problem methodology is used to evaluate the permeability of the ferromagnetic materials from the measurement of the impedance of a sensor. The linear case is studied by a harmonic A-V formulation of the Maxwell equations. The nonlinear case is elaborated by a first harmonic equivalent permeability. The Nelder-Mead simplex search method is then used to solve the inverse problem. To obtain the best operating frequency of the installation, the sensitivity of the sensor is calculated as a function of the frequency 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.

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Meet Our Editors

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