Showing papers presented at "IEEE Conference on Electromagnetic Field Computation in 2011"
21 Apr 2011
TL;DR: In this paper, a non-radiative energy transformer based on ''strong coupling'' between two coils which are separated physically by medium-range distances, is proposed to realize efficient wireless energy transfer.
Abstract: A non-radiative energy transformer, commonly referred as Witricity and based on `strong coupling' between two coils which are separated physically by medium-range distances, is proposed to realize efficient wireless energy transfer. The distance between the resonators can be larger than the characteristic sizes of each resonator. Non-radiative energy transfer between the first resonator and the second resonator is facilitated through the coupling of their resonant-field evanescent tails. The proposed system operates as traditional inductive magnetic coupling devices when the operating frequencies are not the resonant frequency. Corresponding finite element analysis (FEA) and experiments have been carried out to facilitate quantitative comparison. Compared with typical magnetic inductive coupling energy transmission devices, the efficiency of the proposed system is much higher. This investigation indicates that it is feasible to use wireless energy transfer technology to recharge batteries, particularly in implant devices.
256 citations
21 Apr 2011
TL;DR: In this paper, the authors investigate a relay effect to extend the energy transfer distance and show that the efficiency of power transfer can be improved significantly using one or more relay resonators.
Abstract: Wireless power transfer using strongly coupled electromagnetic resonators is a recently explored technology. Although this technology is able to transmit electrical energy over a much longer distance than traditional near field methods, in some applications, its effective distance is still insufficient. In this paper, we investigate a relay effect to extend the energy transfer distance. Theoretical analysis is performed based on a set of coupled-mode equations. Experiments are conducted to confirm the theoretical results and demonstrate the effectiveness of the relay approach. Our results show that the efficiency of power transfer can be improved significantly using one or more relay resonators. This approach significantly improves the performance of the present two-resonator system and allows a curved path in space to be defined for wireless power transfer using smaller resonators.
182 citations
21 Apr 2011
TL;DR: The novel analytical expressions are proposed for calculation of faulty machine inductances from healthy machine parameters and can be used in the circuit based fault models.
Abstract: A time stepping FEM is performed for study of PM motor with inter-turn fault. The novel analytical expressions are proposed for calculation of faulty machine inductances from healthy machine parameters. The proposed expressions are validated by FEM and can be used in the circuit based fault models. Finally, the FEM is applied for studying the PM machine under various fault conditions.
93 citations
21 Apr 2011
TL;DR: In this paper, a flux-switching permanent magnet linear generator (FSPMLG) was proposed for wave energy extraction, and the optimal structure of the linear generator has advantages of better voltage waveform and minimal cogging effect.
Abstract: In this paper, a novel flux-switching permanent-magnet linear generator (FSPMLG) is proposed for wave-energy extraction. The 2-D finite-element method (FEM), combined with the equivalent circuit, is implemented to investigate the electromagnetic characteristics of the FSPMLG. The optimal structure of the linear generator has advantages of better voltage waveform and minimal cogging effect. The numerical analysis is validated by experiments. The results indicate that these kinds of linear generators are suitable for the application of wave energy conversion.
85 citations
01 May 2011
TL;DR: In this article, an optimization technique is adopted in order to determine the best shape of the flux barriers with the objective of achieving a smooth torque with a high average value, with regards to both its average value and ripple.
Abstract: Interior permanent magnet (IPM) motors are normally designed with two or more flux barriers per pole. The form of such flux barriers has a direct impact on the torque developed by the IPM motor, with regards to both its average value and ripple. The Machaon structure includes flux barriers of different shape, aimed at reducing the torque ripple. Their shape depends on the number of poles, number of slots, winding arrangements, and PM volume used in the rotor. An optimization technique is adopted in order to determine the best shape of the flux barriers with the objective of achieving a smooth torque with a high average value.
75 citations
21 Apr 2011
TL;DR: In this article, second-order complex Pade approximants are used to compare frequency domain (FD) versus time-domain (TD) simulations of local optical responses and the transmission-reflection spectra for a plasmonic nanostructure.
Abstract: We discuss second-order complex Pade approximants which give a systematic approach to time-domain modeling of dispersive dielectric functions. These approximants, which also reduce to the classical Drude, Lorentz, Sellmeier, critical points and other models upon appropriate truncation, are used to compare frequency domain (FD) versus time-domain (TD) simulations of local optical responses and the transmission-reflection spectra for a plasmonic nanostructure. A comparison is also made using auxiliary differential equations (ADE), and second order recursive convolution (RC) formulations embedded in finite-difference, finite-volume, and finite-element time-domain solvers.
57 citations
21 Apr 2011
TL;DR: In this article, the authors investigated the feasibility of the proposed rotating magnetic field eddy-current (RoFEC) probe which is composed of three windings excited by three-phase ac current.
Abstract: Rotating magnetic field eddy-current (RoFEC) probe for nondestructive evaluation of steam generator tubes in a nuclear power plant offers an alternate method that has compact configuration and higher speed compared to traditional bobbin coil, rotating probe coils, and array probes. This paper investigates the feasibility of the proposed RoFEC eddy-current probe which is composed of three windings excited by three-phase ac current and does not require mechanical rotation of probe. Results of finite-element modeling using reduced magnetic vector potential (RMVP) formulation are presented for modeling the inspection of ferromagnetic and nonferromagnetic tubes. Design parameters of the excitation coils and GMR pick-up sensor are optimized by means of a parametric study.
38 citations
21 Apr 2011
TL;DR: In this article, a method to calculate the 3D ionized field under HVDC transmission lines is proposed based on Deutsch's assumption which is simple, fast, and easy to use and the computation cost of which is low.
Abstract: The ionized field under HVDC transmission lines is actually a 3-D field with considering the influence of wires sag, towers, up-and-downs on the ground, surrounding buildings and other situations and little of its calculation method has been reported. In this paper, a method to calculate the 3-D ionized field under HVDC transmission lines is proposed based on Deutsch's assumption which is simple, fast, and easy to use and the computation cost of which is low. After the validity of the method is testified, some examples are analyzed and some conclusion are given.
33 citations
21 Apr 2011
TL;DR: An effective methodology for a robust global optimization of electromagnetic devices is developed based on the gradient index and multi-objective optimization method and the performance and robustness of the obtained optimal designs from the proposed algorithm are investigated.
Abstract: An effective methodology for a robust global optimization of electromagnetic devices is developed based on the gradient index and multi-objective optimization method. The method transforms a given optimization problem into a multi-objective optimization one by adding another optimization target for minimizing the gradient index. The performance and robustness of the obtained optimal designs from the proposed algorithm are investigated through a numerical experiment with the TEAM Workshop Problem 22.
32 citations
21 Apr 2011
TL;DR: In this paper, a transverse-flux PM linear machine is investigated for series hybrid electric vehicles (HEVs), which is composed of a free-piston engine and a permanent-magnet linear machine.
Abstract: Free-piston energy converter, composed of a free-piston engine and a permanent-magnet (PM) linear machine, is a promising generator concept for series hybrid electric vehicles (HEVs). In this paper, a novel transverse-flux PM linear machine is investigated for such applications. Unlike conventional transverse-flux machines, the proposed machine features simple mechanical structure. Flux leakage of the proposed machine is analyzed, and parameters of the machine are optimized by finite-element method (FEM). Compared with conventional flux configurations, such as radial flux, axial flux and Halbach, the proposed transverse-flux topology showed advantages in low cogging force, low thrust fluctuation, and high efficiency. A prototype was designed and manufactured. Further experiments indicated satisfactory load characteristic of the machine.
31 citations
21 Apr 2011
TL;DR: A meshless method based on local boundary integral equations (LBIEs) to solve electromagnetic problems to solve three-dimensional scalar boundary value problems arising in electromagnetism.
Abstract: In this paper, we apply a meshless method based on local boundary integral equations (LBIEs) to solve electromagnetic problems. The discretization process is carried out through the use of special basis functions that, unlike the Finite Element Method, are not confined to an element and do not require the support of an underlying mesh. The approach herein developed can be applied to general three-dimensional scalar boundary value problems arising in electromagnetism.
21 Apr 2011
TL;DR: An optimal design of surface-mounted permanent magnet motor geometry for achieving minimum torque ripple, minimum RMS value of phase current, and minimum total harmonic distortion of phase currents, simultaneously is dealt with.
Abstract: This paper deals with an optimal design of surface-mounted permanent magnet motor geometry for achieving minimum torque ripple, minimum RMS value of phase current, and minimum total harmonic distortion of phase currents, simultaneously. A classic multiobjective function is formed as a combination of these single objectives. A dynamic physics-based phase variable modeling approach is used to indirectly couple the motor geometry in the finite element domain to the drive circuit in a simulink environment. The physical behavior of motor is calculated by nonlinear transient FE analysis with motion. A fast hybrid genetic-particle swarm optimization process is developed for shape optimization of the motor. The results before and after optimization show the expected performance improvements while reducing magnet material and copper size.
21 Apr 2011
TL;DR: In this article, a time-periodic explicit error correction (TP-EEC) method was proposed for the convergence acceleration to a steady state in transient analysis of synchronous machines.
Abstract: This paper develops the time-periodic explicit error correction (TP-EEC) method for the convergence acceleration to a steady state in transient analysis of synchronous machines. The methods to deal with the movement of the rotor and different time-periodicity in the fixed and moving parts of the mesh are investigated. Furthermore, we propose the novel TP-EEC method based on the polyphase time periodic condition. Numerical results verify the effectiveness of the developed methods.
21 Apr 2011
TL;DR: This paper developed the formulation of the infinite element by adopting the characteristic of conventional edge elements, resulting in a sparse and symmetric matrix, which has the advantage of drastically reducing the computational burden with keeping the analyses' accuracy.
Abstract: This paper proposes a novel effective method for open boundary problems by using the finite-element method (FEM) with a new formulation of the infinite edge element. We developed the formulation of the infinite element by adopting the characteristic of conventional edge elements, resulting in a sparse and symmetric matrix. This proposed technique with the infinite edge element has the advantage of drastically reducing the computational burden with keeping the analyses' accuracy. Some numerical examples which demonstrate the validity of the proposed method are presented.
21 Apr 2011
TL;DR: In this paper, an extended version of PEEC is used to study a real device and results are compared with experimental ones in order to achieve a very good behavior of the TEM cell over a wide frequency range of operation.
Abstract: Two-port TEM cells with rectangular cross section are commonly used to produce plane electromagnetic waves with high electric field. The non-uniform structure makes the use of numerical methods extremely useful in the design phase in order to achieve a very good behavior of the TEM cell over a wide frequency range of operation. In this paper an extended version of PEEC is used to study a real device and results are compared with experimental ones.
21 Apr 2011
TL;DR: In this article, the magnetic field analysis with the voxel modeling is investigated, and the results obtained from the proposed method sometimes converge to true values slowly, whereas it provides acceptable results.
Abstract: To establish a large-scale magnetic field analysis, the magnetic field analysis with the voxel modeling is investigated. To reduce the number of elements, the nonconforming technique is introduced. The accuracy of flux densities, eddy current densities, and forces obtained from the nonconforming voxel modeling is verified by comparing with those obtained from the ordinary voxel modeling in a simple 2-D model. Moreover, the proposed method is applied to a 3-D eddy current model as well as to a 2-D nonlinear IPM motor model. It is shown that the results obtained from the proposed method sometimes converge to true values slowly, whereas it provides acceptable results.
21 Apr 2011
TL;DR: In this paper, a dynamic finite element model for calculating iron loss in ferromagnetic non-oriented grain laminations under PWM excitation was proposed, which accounts for static hysteresis, classical eddy currents and anomalous losses.
Abstract: This paper introduces a dynamic finite element model for calculating iron loss in ferromagnetic non-oriented grain laminations under pulse-width modulation (PWM) excitation. The proposed methodology accounts for static hysteresis, classical eddy currents and anomalous losses and has been validated by measurements in Epstein device in different cases of PWM voltage waveforms. The model is based on a particular 2-D finite-element technique by using standard static iron lamination characteristics and offers sufficient accuracy in all studied cases.
21 Apr 2011
TL;DR: This paper designs several irregularly shaped microstrip antenna structures using a new version of Binary Particle Swarm Optimization (BPSO) algorithm in which the velocity calculation is modified towards a more accelerated and still robust search procedure, particularly aimed for software-defined radio (SDR) applications.
Abstract: In this paper, several irregularly shaped microstrip antenna structures are designed using a new version of Binary Particle Swarm Optimization (BPSO) algorithm in which the velocity calculation is modified towards a more accelerated and still robust search procedure, particularly aimed for software-defined radio (SDR) applications. The optimization results are compared using both the modified and the conventional BPSO algorithms. Pros and cons are studied in terms of optimization length, convergence speed and final design conformability to desired objectives. It is depicted that the modified BPSO achieves the design criterion considerably faster than the conventional one, at the cost of slightly limiting particle exploration ability.
21 Apr 2011
TL;DR: In this paper, a wireless energy transfer system based on resonant energy transfer technology for power transmission and recharging of electrical devices is studied, and the relationship between the energy transfer efficiency and several key parameters of the system is analyzed using finite-element method.
Abstract: A wireless energy transfer system based on resonant energy transfer technology for power transmission and recharging of electrical devices is studied. The relationship between the energy transfer efficiency and several key parameters of the system is analyzed using finite-element method. Thin film resonant cells, consisting of a tape coil on one layer, which is separated by an insulation layer to form a capacitor with another layer, are fabricated. These cells are light, compact, and flexible, and provide convenience and flexibility in the design of wireless devices. The feasibility of this system is demonstrated using practical measurements to showcase its performance.
21 Apr 2011
TL;DR: In this article, a design exploiting full wave numerical simulation of a dual resonant structure with an aim to sense small amounts of chemical and biochemical materials is proposed and investigated exploiting full-wave numerical simulation, where the structure is energized with free space radiation in the terahertz regime.
Abstract: A design is proposed and investigated exploiting full wave numerical simulation of a dual resonant structure with an aim to sense small amounts of chemical and biochemical materials. The structure is energized with free space radiation in the terahertz regime. Thanks to its asymmetric geometry high quality trapped mode resonances are excited. By selectively loading the structure with only small amounts of probe material, a relatively large shift in the frequency response may be achieved. The concept is demonstrated through simulation, while optimization of the structure and the analyte loading is attempted.
21 Apr 2011
TL;DR: In this article, the authors focus on the modeling of multilayer structures under dynamic excitation and the calculated ME coefficient versus frequency shows the enhancement of the magnetoelectric effect at mechanical resonance in accordance with experimental measurements.
Abstract: The magnetoelectric (ME) effect in composite materials results from the combination of the magnetostrictive effect and the piezoelectric effect via elastic interaction. This work focuses on the modeling of multilayer structures under dynamic excitation. The calculated ME coefficient versus frequency shows the enhancement of the ME effect at mechanical resonance in accordance with experimental measurements. The impact of electric conductivity is investigated. Applications on the ME sensor and tunable inductor are proposed.
21 Apr 2011
TL;DR: In this paper, proper generalized decomposition (PGD) and proper generalized decomposition (FGD) have been used to model polymeric proton exchange membranes (PEM) at the heart of fuel cells.
Abstract: Modeling polymeric proton-exchange membranes (PEM) at the heart of fuel cells requires the solution of highly nonlinear partial differential equations in very thin and flat domains. Recently, the Proper Generalized Decomposition methods have emerged as particularly promising methods for these types of problems. This paper introduces the basics of this novel class of approaches to PEM modeling and highlights their potential benefits.
21 Apr 2011
TL;DR: New hierarchical vector basis functions for quadrilateral cells are introduced, and the matrix condition numbers associated with their use are compared to those of existing vector basis families to assess the relative linear independence of the functions.
Abstract: New hierarchical vector basis functions for quadrilateral cells are introduced, and the matrix condition numbers associated with their use are compared to those of existing vector basis families to assess the relative linear independence of the functions. Scale factors are employed to improve the condition numbers. In addition, the proper use of subsets of these families to transition from one order to another (as needed for adaptive p-refinement) without exciting spurious modes is considered.
21 Apr 2011
TL;DR: In this paper, the meshless Local Petrov-Galerkin (MLPG) method is used, based on a local weak form tested with the Heaviside step function and the field is approximated by the Point Interpolation method using radial basis function with additional polynomial basis (RPIMp).
Abstract: This paper describes a meshless approach to obtain solutions for propagating microwave problems The Meshless Local Petrov-Galerkin (MLPG) method is used, based on a local weak form tested with the Heaviside step function The field is approximated by the Point Interpolation method using radial basis function with additional polynomial basis (RPIMp) TEAM workshop problem 18 is solved and its solution is compared with references from the literature The results are in good agreement, showing that MLPG can be used as a good alternative to finite elements for this kind of problems
01 May 2011
TL;DR: Methods for homology basis selection within the modeling software are discussed and a good basis should be as clear and informative to the user as possible and to indicate basis elements' relation to the boundary conditions.
Abstract: With heuristics, computational homology is able to extract the bases of homology spaces of a domain covered with a cellular mesh with an acceptable efficiency. In this paper, methods for homology basis selection within the modeling software are discussed. A good basis should be as clear and informative to the user as possible and to indicate basis elements' relation to the boundary conditions.
23 May 2011
TL;DR: In this paper, a simplified singularity decomposition-explicit error correction (SD-EEC) method is developed to improve the convergence for steady-state analysis, which is applied to an interior permanent magnet (IPM) and an induction motor.
Abstract: In order to improve the convergence for steady-state analysis, the simplified singularity decomposition-explicit error correction (SD-EEC) method is developed. This paper proposes techniques to apply the simplified SD-EEC method to an interior permanent magnet (IPM) motor and to an induction motor. The usefulness of the techniques is verified through the applications to an interior permanent magnet (IPM) motor and an induction motor.
21 Apr 2011
TL;DR: A multiphysics analysis procedure that comprehensively considers electromagnetic, mechanical, and acoustic coupling effects is suggested and the experimental results confirm the validity of the proposed analysis procedure.
Abstract: Mobile phones have become more versatile as a result of advances in mobile communication technology. The latest mobile phones are able to provide dazzling multimedia entertainment with portability. A microspeaker has become a generic electromechanical part of mobile phones that enables multimedia features. Therefore, the performance of the microspeaker must be improved in line with the increasing demand for high-quality sound produced by the phone. Sound pressure level (SPL) and total harmonic distortion (THD) are the two most common evaluation criteria that are used to quantify the performance of the microspeaker. Therefore, it is necessary to implement an analysis procedure that predicts and quantifies the SPL and THD characteristics. This manuscript suggests a multiphysics analysis procedure that comprehensively considers electromagnetic, mechanical, and acoustic coupling effects. The experimental results confirm the validity of the proposed analysis procedure.
21 Apr 2011
TL;DR: In this paper, a procedure is proposed to accurately model thin wires in lossy media by finite element analysis based on the determination of a suitable element width in the vicinity of the wire, which strongly depends on the wire radius to yield accurate results.
Abstract: A procedure is proposed to accurately model thin wires in lossy media by finite element analysis. It is based on the determination of a suitable element width in the vicinity of the wire, which strongly depends on the wire radius to yield accurate results. The approach is well adapted to the analysis of grounding systems. The numerical results of the application of finite element analysis with the suitably chosen element width are compared with both analytical results and those computed by a commercial package for the analysis of grounding systems, showing very good agreement.
21 Apr 2011
TL;DR: In this article, the authors extended the finite element method for transient simulation of the deformation of a thin magneto-elastic film to the case of permanent magnetoelastic materials.
Abstract: We are interested in the deformation of a thin magnetoelastic film. This has many possible applications, such as in microfluidic actuators and sensors. In previous articles a finite element method has been used for transient simulation of the deformation of a film, for the special case of soft magnetic material only. Here the approach is extended to the case of permanent magnetoelastic materials. The key enhancements required for simulation of magnetoelastic materials are a nonlinear hyperelastic Mooney-Rivlin material model, addition of an implicit system of equations for the scalar magnetic potential, and a more complex asymmetric Maxwell stress tensor. A simple test problem was constructed, and simulations for a soft magnetic film and a permanent magnetic film are compared.
21 Apr 2011
TL;DR: In this paper, an analytical magnetic model using Coulombian approach is used and coupled with a mechanical deformation model for a cantilever beam to evaluate contact size and contact force.
Abstract: This paper presents a methodology and a tool for magnetic and mechanical deformation coupling using numerical and analytical modeling. An analytical magnetic model using Coulombian approach is used and coupled with a mechanical deformation model for a cantilever beam to evaluate contact size and contact force. Such a coupling is not available using numerical solution. This paper details the deformation and contact analysis, which is validated by finite element simulation and also details the coupling approach. Such a modeling is dedicated to an optimization process of magnetic MEMS/NEMS in general and to magnetic nano switch in particular.