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This paper proposes a way to represent the anisotropic nonlinear superconducting properties using a discrete model for magnetization with the corresponding critical parameters, equivalent to the Power Law model for currents. This simplified model makes it possible to analyze magnetic systems with superconducting elements in a stationary mode, which reduces the calculation time. Using of proposed model is demonstrated by the calculation of force interactions between high-temperature superconducting (HTS) samples and permanent magnet in zero-field-cooling (ZFC) and field-cooling (FC) modes. HTS bulks in the form of a prism and stack made of HTS tape are considered. The calculation of the electromagnetic field was carried out using the method of integral equations for field sources. The data of calculations are compared with the results of experimental studies. [ABSTRACT FROM AUTHOR]

Accurate and simple magnetic material behavior law is necessary to correctly model complete electromagnetic systems. In this paper, a new formulation based on the scalar quasi-static hysteresis Preisach model extended to dynamic behavior using fractional derivation dynamic contribution is proposed. The fractional contribution is solved using convolution which highly reduces the numerical issues. The order of the fractional derivation provides a new degree of freedom and allows to correctly obtain simulation results on a very large frequency bandwidth. By using such formulation, space discretization techniques (finite differences, finite elements) are avoided which are highly space and time consuming while keeping the global simulation results precise. The numerical implementation of the problem and some experimental validations are shown in this paper. [ABSTRACT FROM AUTHOR]

The nonconformal domain decomposition methods (DDMs) of the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) are presented for computing large electromagnetic scattering/radiation problems. The numerical performance of different transmission conditions between finite element method (FEM) subdomains, and FEM and BI domains is studied in this paper. The Dirichlet transmission condition (DTC) employed at the interface between FEM and BI domains has faster convergence than the Robin-type transmission condition, and this finding is different from the conclusions for the FEM DDMs published in the literature. Furthermore, the cement-element (CE)-based dual-primal finite element tearing and interconnecting (FETI-DP) DDM has faster convergence than the Lagrange-multiplier-based FETI-DP method under the FE-BI system, and is also different from that under the system of the FEM with the absorbing boundary condition (FEM-ABC). It shows that the DDMs of FE-BI-MLFMA have some essential differences from those of FEM-ABC. The analysis of these numerical phenomena is presented in this paper. Further comparison between the DDMs of FE-BI-MLFMA and FEM-ABC demonstrates that the DDMs of FE-BI-MLMFA have essential advantages over those of FEM-ABC. Various numerical experiments confirm the accuracy, efficiency, and flexibility of the nonconformal DDM of FE-BI-MLFMA, which is the CE-based FETI-DP DDM with DTC connecting FEM and BI. [ABSTRACT FROM AUTHOR]

This paper proposes a robust frequency-domain method to tune the d–q decoupled control system used in Modular Multilevel Converter-type Voltage Source Converter (MMC-VSC) systems. A linearized state-space model of the MMC-VSC system is developed and used to calculate the stability-related frequency-domain attributes. The controller design problem is formulated as an optimization problem. In this paper, the simulated annealing optimization technique is applied to find the proportional-integral (PI) controller parameters that give desired damping for the oscillatory modes and desired values for decaying exponential modes. The efficacy of this method is tested on the electromagnetic transient model of a two-terminal MMC-VSC system on the real-time digital simulators, and the results are provided in this paper. Finally, tuned controller parameters for different ac system strengths are discussed and it is shown that this mathematical model is suitable to tune the PI-controller parameters for MMC-VSC systems connected to strong as well as weak ac networks. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics of the electromagnetic noise radiated by an external rotor in-wheel motor (IWM) are investigated with the Doppler effect taken into consideration. First, Maxwell stress tensor method is employed to derive electromagnetic forces on the magnet surface. The effect of common current harmonics is also analyzed. Then, a structural model of the rotor is built and modal test is conducted to validate the model. Nodal forces, which are calculated by finite element method, are transferred from the electromagnetic mesh to the structural model for further vibration prediction. Finally, boundary element method is used to calculate the noise radiated by the rotor. In particular, the Doppler effect is considered. The calculated results are validated by the noise test. It is found that the end cap contributes more to the overall noise than the shell, and obvious sound directivity appears in the noise of the IWM. The noise measured perpendicular to the outer end cap is larger than that measured in other directions. In addition, the Doppler effect would induce additional side-frequency components around high-frequency peaks in the external rotor motor. [ABSTRACT FROM PUBLISHER]

It is popular to use moving elements to improve heating uniformity during microwave heating under some situations. However, it is still a challenge to simulate moving elements during microwave heating due to the complexity of mathematical modeling. In this paper, a novel continuous algorithm based on implicit function and level set methods is developed to compute this heating process. By introducing the implicit function and level set methods, the moving region’s properties are set as a function of space coordinate and time, which means that the movement of the elements is represented by the variation of the parameters. In addition, with the coordinate transformation, the coupling process of electromagnetic field and heat transfer in microwave heating can be performed. A 2-D applicator model and a 3-D applicator model with a rotating turntable are used to illustrate the proposed method in detail. Experiments are also conducted to testify the validity of the proposed method. The results obtained by the proposed method are in accordance with those obtained by experiments. Moreover, compared with conventional methods, the proposed method is more accurate and efficient. [ABSTRACT FROM AUTHOR]

This paper describes a two-dimensional (2-D) analytical model to predict the magnetic field distribution in axial-field magnetic gears by using the sub-domain method. The sub-domain method consists in solving the partial differential equations linked to the Maxwell's equations in each rectangular region (magnets, air gaps, and slots) by the separation of variables method. The proposed model is based on a two-dimensional approximation for the magnetic field distribution (mean radius model) i.e. the problem is solved in 2-D Cartesian coordinates. One of the main contributions of the paper concerns the analytic solution of the magnetic field in a slot open on the two sides (space between the ferromagnetic pole-pieces). Moreover, it is shown that the analytical model and the 3-D finite elements simulations follow the same trends in the determination of the optimum values for the geometrical parameters. As the analytical model takes less computational time than 3-D numerical model, it can be used as an effective tool for the first step of design optimization. [ABSTRACT FROM PUBLISHER]

Determination of the distribution of electromagnetic energy inside electrically large enclosed spaces is important in many electromagnetic compatibility applications, such as certification of aircraft and equipment shielding enclosures. The field inside such enclosed environments contains a dominant diffuse component due to multiple randomizing reflections from the enclosing surfaces. The power balance technique has been widely applied to the analysis of such problems; however, it is unable to account for the inhomogeneities in the field that arise when the absorption in the walls and contents of the enclosure is significant. In this paper, we show how a diffusion equation approach can be applied to modeling diffuse electromagnetic fields and evaluate its potential for use in electromagnetic compatibility applications. Two canonical examples were investigated: a loaded cavity and two cavities coupled by a large aperture. The predictions of the diffusion model were compared to measurement data and found to be in good agreement. The diffusion model has a very low computational cost compared to other applicable techniques, such as full-wave simulation and ray-tracing, offering the potential for a radical increase in the efficiency of the solution high frequency electromagnetic shielding problems with complex topologies. [ABSTRACT FROM PUBLISHER]

Metamaterials with tunable negative permeability are proposed and investigated theoretically in this paper. First, the model of the dielectric bilayer sphere embedded in the dielectric substrate is put forward. Second, expressions of the electromagnetic fields in the model are derived based on the Mie scattering theory, and the general formula for the effective permeability of the model is deduced via the Maxwell-Garnett theory, which is further verified through the simulation results. Finally, the tunable bandwidth of the negative permeability of the metamaterials changing with the geometrical parameters is investigated based on the full-wave simulations, and the relative mechanisms are also discussed. It is believed that the results would be helpful for the practical applications of the metamaterials, and the metamaterials with tunable negative permeability proposed in the paper would facilitate the constructions of the left-handed materials in some degree. [ABSTRACT FROM PUBLISHER]

The main objective of this paper is to provide an efficient computational model for fast and accurate calculation of electromagnetically induced vibrations in electrical machines. Although a three-phase permanent-magnet synchronous machine has been used in this paper, the same methodology can be extended to other types of electric machinery. A brief comparison between the different methods for structural analysis in electrical machines is introduced. The method proposed in this paper uses finite-element analysis in order to extract the impulse responses that are used in calculating the vibration. A field reconstruction method is used for the electromagnetic field analysis. [ABSTRACT FROM PUBLISHER]

This paper presents an exhaustive simulation study performed to validate the adequacy of the equivalencing method promoted by the National Renewable Energy Laboratory for modeling wind power plants by single- and multiple-machine equivalents. The main simulation results are presented for a number of steady state and transient wind turbine generator operating conditions following various faults and a typical low-voltage ride through. The impact of protection systems such as the crowbar is also taken into account. The aggregation technique has shown to be adequate for load flow, stability, and electromagnetic transient studies with limitations, as presented in the paper. [ABSTRACT FROM AUTHOR]

The evaluation of the lightning performance of overhead lines requires, mainly for distribution lines, the calculation of the voltages induced by nearby lightning strokes hitting the ground. Generally, when calculating lightning-induced voltages using the time-domain approach and the TEM assumption, the most time-consuming stage is the calculation of the source terms of the coupling equations, which means, in turn, the electromagnetic field radiated by the lightning channel. Hence, simplified approaches are still desirable in order to save computational time. Analytical solution of the lighting-originated electric- and magnetic field is available in literature for the case of an ideal transmission-line (TL) return-stroke model with channel-base current having a stepwise waveshape. This paper describes an analytical approach that applies to the case of a general waveshape of the channel-base current, based on the piecewise straight-line approximation, in cylindrical coordinates, which is functional when using the TL return-stroke current model and the Agrawal et al. coupling model. This paper reports the exact solution for the case of trapezoidal waveshape of the current at the base of the channel and the analytical solution for the case of piecewise linear waveform. [ABSTRACT FROM AUTHOR]

This paper deals with the use of the integrated circuit electromagnetic model (ICEM) to analyze, predict, and optimize autocompatibility and electromagnetic emission at chip and system level. ICEM is currently under standardization process (IEC62014- 3). The basic ICEM architecture is composed of a power distribution network model and an internal current source modeling digital activity. Such an approach enables the description of any kind of digital or mixed-signal design. This model is useful either for the IC manufacturer or the system manufacturer. The power distribution network of a printed circuit board (PCB) can be optimized using this model by choosing the number and the right values of decoupling capacitors as well as the size of power planes. The IC manufacturer may check out the autocompatibility of an IC and determine the number of power pins as well as the package to be used. As an example, jitter analysis of an integrated phase-locked-loop can be performed using ICEM. This paper demonstrates that this jitter can be predicted by simulation and that corrective solutions can be provided and checked out before implementation. [ABSTRACT FROM AUTHOR]

This paper presents a field-circuit-coupled method to investigate differences between intrinsic and measured permittiveties for a Mn-Zn ferrite. Electric and magnetic fields in a flat cylindrical ferrite, which is used here to construct a ferrite capacitor, are solved analytically. Then, complex power supplied to the capacitor is calculated. On the basis of the complex power, parametears in an equivalent circuit for the ferrite capacitor are extracted. The paper examines the validity of the developed mathematical model. Numerical results show that for a ferrite with high permeabilities, measured permittivities follow intrinsic values well at low frequency but fail to embody the intrinsic values when the frequency runs above several hundred kilohertz. Numerical results also demonstrate that the dimensions of the sample under investigation play a role in measurement errors. The larger the radius of the cylindrical ferrite is, the higher the errors are. Correction curves are generated, from which the measured permittivities can be corrected to reflect the intrinsic values. [ABSTRACT FROM AUTHOR]

Solid dielectrics have been widely investigated as potential attractive candidates in compact portable pulsed-power systems. Slow-wave structure with good dispersion characteristics and broad transmission band can be used to increase the pulse duration while the size of pulse-forming line (PFL) decreases. In this paper, we present two different slow-wave structures, the tape helix for coaxial-line and the meander-line structure for the planar line, to increase the pulse duration of solid PFLs based on dispersion analysis. At first, the characteristic impedances, electric length, and dispersion curve of the PFL with the slow-wave structure are calculated by the electromagnetic dispersion theory. Based on the theoretical calculations, the PFLs are designed and simulated by the electromagnetic field tool. Finally, some test results on the PFLs are introduced. Currently, both the Al2O3 ( \varepsilon r= 9.3 ) helical PFL and the glass–ceramic ( \varepsilon r = 225 ) meander-line PFL can deliver a pulsewith 50-ns width, of which the dimension is \phi ~67~\mathrm mm \times 305 mm and 95~\mathrm mm \times 95~\mathrm mm\times 4 mm, respectively. [ABSTRACT FROM PUBLISHER]

The aim of this paper is to highlight the capabilities of a new hybrid analytical modeling (HAM) approach for the analysis and design of various electromagnetic structures. After an introduction, where the aim of the development of this modeling approach is presented, the modeling approach is described. The new HAM is based on a strong coupling of the magnetic equivalent circuits method and analytical models (AMs). The AM, based on the formal solution of Maxwell’s equations, is established thanks to the separation of variables method. The HAM is applied to different permanent magnet electric machine structures, and the results are validated extensively by comparison with the finite-element analyses. [ABSTRACT FROM AUTHOR]

Numerical techniques for calculating electromagnetic fields within three-dimensional surfaces are computationally intensive. Therefore, this paper presents the application of a mode-matching technique developed for analyzing electromagnetic scattering from periodic comb surfaces illuminated by a plane wave. A set of linear equations has been developed to calculate mode coefficients of the field distribution for both E- and H-polarized incident waves. Analysis is performed for two cases where the comb thickness is either infinitely thin or of a finite thickness. The technique is shown to accurately predict both field intensities within the near-field of the periodic surface and far-field scattering patterns. Results are compared to those obtained using the finite integration techniques (FIT) implemented in CST Microwave Studio. Furthermore, numerical results are compared to measurements of an aluminum prototype. Additional far-field scattering measurements using a bi-static system provide additional confidence in CST simulations and the mode-matching methods presented here. [ABSTRACT FROM PUBLISHER]

A novel hybrid method, combining the conformal time domain finite integral theorem with the conformal particle-in-cell method, is applied to accurately analyze multipactor phenomena. To successfully apply this hybrid method in microwave devices, we propose a novel power-to-amplitude transformation technique in this paper. The PAT technique is effective and convenient to bridge the gap between the average input power in experiments and electromagnetic field amplitude in numerical simulations. In the end, a numerical example is given to demonstrate the effectiveness and accuracy of the proposed method, whose superiority is also greatly verified by experiments. [ABSTRACT FROM PUBLISHER]

The Warp code (and its framework of associated tools) was initially developed for particle-in-cell simulations of space-charge-dominated ion beams in accelerators, for heavy-ion-driven inertial fusion energy, and related experiments. It has found a broad range of applications, including nonneutral plasmas in traps, stray electron clouds in accelerators, laser-based acceleration, and the focusing of ion beams produced when short-pulse lasers irradiate foil targets. We summarize novel methods used in Warp, including: time-stepping conducive to diagnosis and particle injection; an interactive Python-Fortran-C structure that enables scripted and interactive user steering of runs; a variety of geometries (3-D $x$ , $y$ , $z$ ; 2-D $r$ , $z$ ; 2-D $x$ , $y$ ); electrostatic and electromagnetic field solvers; a cut-cell representation for internal boundaries; the use of warped coordinates for bent beam lines; adaptive mesh refinement, including a capability for time-dependent space-charge-limited flow from curved surfaces; models for accelerator lattice elements (magnetic or electrostatic quadrupole lenses, accelerating gaps, etc.) at user-selectable levels of detail; models for particle interactions with gas and walls; moment/envelope models that support sophisticated particle loading; a drift-Lorentz mover for rapid tracking through regions of strong and weak magnetic field; a Lorentz-boosted frame formulation with a Lorentz-invariant modification of the Boris mover; an electromagnetic solver with tunable dispersion and stride-based digital filtering; and a pseudospectral electromagnetic solver. Warp has proven useful for a wide range of applications, described very briefly herein. It is available as an open-source code under a BSD license. This paper describes material presented during the Prof. Charles K. (Ned) Birdsall Memorial Session of the 2013 IEEE Pulsed Power and Plasma Science Conference. In addition to our overview of the computational methods used in Warp, we summarize a few aspects of Ned's contributions to plasma simulation and to the careers of those he mentored. [ABSTRACT FROM PUBLISHER]

An automatic mesh generation method employing a dynamic bubble system can provide a high-quality mesh for electromagnetic finite element analysis. However, it takes a very long time to compute bubbles' movement when a mesh with a large number of elements is generated. The bubbles move according to a force among them, such as the van der Waals force. However, the force received from bubbles of very far distance can be ignored. Therefore, it is unnecessary to calculate the force from all the bubbles. In this paper, we propose a subdivided dynamic bubble system in order to shorten the computation time. The proposed method considers the analysis region to be divided into some tetrahedral subdivisions, and then the bubbles move independently in the tetrahedral subdivisions. As a result, acceleration of the computation time is achieved. [ABSTRACT FROM AUTHOR]

Fast design procedures of electrical machines require the use of adapted modeling approaches. This is particularly true for axial flux permanent magnet (AFPM) machines, which have an intrinsic 3-D electromagnetic structure. Indeed, accurate modeling of AFPM machines requires the use of 3-D finite-element analysis (3-D FEA), which is highly time consuming, especially at first design stages. This paper presents a new quasi-3-D analytical model (AM) that allows modeling accurately AFPM machines while saving a huge amount of time as compared with 3-D FEA. This new approach combines a multislice AM, which takes into account a part of the 3-D effects, and considers the end-effects by a simple and effective radial dependence modeling of the magnetic field in AFPM machines. [ABSTRACT FROM AUTHOR]

Compared with the most popular DC and other emerging AC magnetic bearings, the AC-DC three-degree-of-freedom hybrid magnetic bearing (AC-DC 3-DOF HMB) invented in our research has a lot of advantages in cost savings and consumption reducing. In this paper, to overcome the insufficiency and shortcomings of the previously established classic model, a new mathematical model for suspension force of AC-DC 3-DOF HMB is deduced again to get more accurate results. To illustrate the improvement in the new model, some validation experiments and contrast experiments are designed and implemented to prove their correctness and accuracy. In the validation experiments, the nonlinearity, linearity, electromagnetic cross-coupling and kinematic cross-coupling of suspension force model are validated, which prove the correctness of the improved mathematical model. In the contrast experiments, the encouraging results between the experimentally measured result and two calculated results (classic and improved model results) show that the improved model is closer to the test results. Moreover, system performance comparison results show the control system based on the new model has stronger anti-disturbance characteristics than that based on the classic model. Thus, the improved modeling results on suspension force of AC-DC 3-DOF HMB is more accurate than the traditional results, even if they share the same modeling method (equivalent magnetic circuit method). So only a change of coefficient could help to significantly improve the accuracy of the mathematical model, and also the improved model instance has important reference value for solving other kinds of hybrid magnetic bearings. [ABSTRACT FROM PUBLISHER]

Magnetic components are widely used in power electronics and are the main cause of electromagnetic couplings. Among them, coils with ferromagnetic cores belong to the class of components that are used the most. However the behavior in terms of radiation and coupling to the environment of these components is not widely explored. This paper defines a more accurate model for coils with toroidal ferrite cores in order to get a better understanding of the coupling they created. Then the effects of the winding layout around a toroidal core are first discussed. It is found that the winding topology is the major parameter controlling both the radiated field pattern and its magnitude. A measurement bench has then been developed to validate the hypothesis made. Finally, numerical and analytic models have been elaborated to predict radiated fields from magnetic components. [ABSTRACT FROM PUBLISHER]

Understanding the importance of saturation of parameters in line-start permanent magnet synchronous machine (LSPMSM) and the scanty available research literature on simplistic methods of determining the magnetizing characteristics of LSPMSM, this paper proposes a novel and yet simplistic approach towards its determination. Experimental investigations have been performed on a laboratory LSPMSM based on the proposed dq axis (two-axis)-based methodology and the measured magnetization characteristics of the machine has been incorporated into the machine model. The measured characteristics have hence been validated through dynamic and steady state performance analyses of the machine under direct online (DOL) starting. Furthermore, performance analysis of the machine has also been performed through the developed machine model with and without incorporating the magnetization characteristics of the machine to elicit the effects of parameter saturation during startup and synchronization of the machine. [ABSTRACT FROM PUBLISHER]

This paper proposes a new quantum cellular automaton (quantum CA) for simulating macroscopic electromagnetic fields. The final target is to simulate the macroscopic electromagnetic fields on a quantum computer. In the proposal approach, Maxwell's historical model, which was explained the nature of electromagnetic fields in 1861, has been modified for a quantum CA model to simulate the electromagnetic fields. Then, a state transition rule for CA is determined by a strategy based on the quantum mechanics and the quantum computation theories. One of originalities of the proposed approach is that a system using quantum gates is superstructed to simulate magneto-static fields from currents. First, a modified Maxwell model for applying to quantum CA was shown. Second, by using the quantum computation theory, a quantum gate system to simulate the magnetic fields from currents was described. Finally, the proposed approach was applied to an example of magnetostatic field simulation. [ABSTRACT FROM PUBLISHER]

This paper presents a new physical model for shielded slow-wave coplanar waveguide structures. This lossy electrical model is based on physical behavior of the transmission lines. It allows a better understanding of the losses distribution along the structure. The ohmic losses in the coplanar strips, as well as the ohmic losses and the eddy current losses in the floating shield strips are studied for transmission lines having different geometrical dimensions and hence electrical characteristics. The model is then validated on different CMOS technologies and leads to the efficient optimization of the slow-wave transmission lines, especially concerning the floating shield dimensions. [ABSTRACT FROM AUTHOR]

In this paper, a physics-based high-frequency (HF) model of switching power converters including the insulated gate bipolar transistor (IGBT) unit cells, heat sink, and connective printed circuit board (PCB) traces combined in a single electrical circuit is presented. The IGBT model includes the HF stray components superimposed on the well-known Hefner IGBT model. The HF components were calculated using a 3-D quasi-static finite element (3-D FE) analysis. The proposed complex model of the IGBT was verified both numerically and experimentally at different switching frequencies. The computed IGBT model was used in a low–high frequency model of a motor-drive system, and the common mode ground current was experimentally verified showing excellent results. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental verification and electromagnetic field analysis for an axial flux permanent magnet (PM) synchronous generator (AFPMSG) with a double-sided PM rotor and slotless stator windings based on analytical field computation to offer improved analytical modeling method. An analytical approach to analyze the magnetic field distribution and estimate the equivalent circuit parameters is presented that dramatically reduces analysis time while maintaining high reliability. Since the flux leakage phenomenon is dominant in the inner and outer radii of this type of AFPMSG, it is specifically considered. In addition, an actual device was fabricated on the basis of one of the analysis models, and used to experimentally verify all of the analysis results. [ABSTRACT FROM PUBLISHER]

Subgridding methods are often used to increase the efficiency of the wave propagation simulation with the Finite-Difference Time-Domain method. However, the majority of contemporary subgridding techniques have two important drawbacks: the difficulty in accommodating dispersive media and the inability for physical interfaces to cross the subgridding interface. This paper presents an extension of the frequency-dependent Huygens subgridding method from one dimension to three dimensions. Frequency dependency is implemented via the Auxiliary Differential Equation approach using the one-pole Debye relaxation model. Numerical experiments indicate that subgridding interfaces can be placed in various Debye media as well as across the physical interface . [ABSTRACT FROM PUBLISHER]

The 120° voltage source inverter driven brushless dc (BLDC) motors are very common in many applications. This paper extends the previous work and presents an improved dynamic average-value model for such BLDC motor-drive systems. The new model is explicit and uses a proper qd model of the permanent magnet synchronous machine with nonsinusoidal rotor flux. The model utilizes multiple reference frame theory to properly include the back EMF harmonics as well as commutation and conduction intervals into the averaged voltage and torque relationships. The commutation angle is readily obtained from the detailed simulation. The proposed model is demonstrated on a typical industrial BLDC motor with trapezoidal back EMF waveforms. The results of studies are compared with experimental measurements as well as previously established models, whereas the new model is shown to provide appreciable improvement. [ABSTRACT FROM PUBLISHER]

In the paper, a novel approach to numerical modeling of tube induction welding is proposed. The coupled electromagnetic and thermal model must take into account also the movement of the metal strip: in order to make possible this kind of simulation in reasonable computation time, a simplified approach to the modeling is presented and discussed. [ABSTRACT FROM PUBLISHER]

In this paper, a time-domain variant of the generalized telegrapher's equations for transient electromagnetic field coupling to a finite-length wire above a lossy half-space is derived. The approach is fully based on the thin-wire antenna theory. The lossy ground effects are taken into account by means of the reflection coefficient approximation. The obtained equations are handled numerically via the Galerkin–Bubnov indirect boundary element method. Computational examples are presented for the case of a single-wire line excited by an electromagnetic pulse excitation source. The obtained results for the induced current along the line are compared with those obtained using 1) the method of moments solution of the electric field integral equation implemented in the numerical electromagnetics code (NEC-4), and 2) the transmission line (TL) theory. It is shown that the results obtained by the proposed method are in excellent agreement with those of NEC-4. It is also shown that the TL approximation yields in general results which are in reasonably good agreement with the full-wave results, especially for the early time response and even beyond the limits of the accuracy of the TL theory. The TL theory can, however, give accurate results only for times before the arrival of the first reflection from the TL terminations and it fails to reproduce accurately the dispersion effects occurring after the first reflection. [ABSTRACT FROM AUTHOR]

The well-known TE/TM decomposition of time-harmonic electromagnetic fields in uniaxial anisotropic media is generalized in terms of four-dimensional differential-form formalism by requiring that the field two-form satisfies an orthogonality condition with respect to two given bivectors. Conditions for the electromagnetic medium in which such a decomposition is possible are derived and found to define three subclasses of media. It is shown that the previously known classes of generalized Q-media and generalized P-media are particular cases of the proposed decomposable media (DCM) associated to a quadratic equation for the medium dyadic. As a novel solution, another class of special decomposable media (SDCM) is defined by a linear dyadic equation. The paper further discusses the properties of medium dyadics and plane-wave propagation in all the identified cases of DCM and SDCM. [ABSTRACT FROM PUBLISHER]

Real-time electromagnetic transient simulation plays an important role in the planning, design, and operation of power systems. Inclusion of accurate and complicated models, such as the universal machine (UM) model and the universal line model (ULM), requires significant computational resources. This paper proposes a digital hardware emulation of the UM and the ULM for real-time electromagnetic transient simulation. It features accurate floating-point data representation, paralleled implementation, and fully pipelined arithmetic processing. The hardware is based on advanced field-programmable gate array (FPGA) using VHDL. A power system transient case study is simulated in real time to validate the design. On a 130-MHz input clock frequency to the FPGA, the achieved execution times for UM and ULM models are 2.5 \mu\s and 1.42 \mu\s, respectively. The captured real-time oscilloscope results demonstrate high accuracy of the emulator in comparison to the offline simulation of the original system in the EMTP-RV software. [ABSTRACT FROM PUBLISHER]

Directly coupled electromagnetic field-electric circuit modeling approach for coupling an electrical machine to its associated external circuit and power electronics has been widely reported in the literature. However, the inclusion of a closed-loop control system, such as conventional vector (field-oriented) control, within a directly coupled electromagnetic field-electric circuit model has not been widely studied. This is partly because it is a rather complex task. This paper introduces a directly coupled electromagnetic field-electric circuit computational model in which a conventional vector control system has been incorporated for detail simulation of vector-controlled electric machinery drive systems. The model has been successfully applied in the design and analysis of a vector-controlled wound field brushless starter-generator system prototype. Comparison between the simulation and test results for both motor and generator modes show excellent correlation that validates the efficacy and computational soundness of the modeling approach. [ABSTRACT FROM AUTHOR]

Electromagnetic scattering by penetrable bodies often is modelled by the Poggio-Miller-Chan-Harrington-Wu-Tsai (PMCHWT) integral equation. Unfortunately the spectrum of the operator involved in this equation is bounded neither from above or below. This implies that the equation suffers from dense discretization breakdown; that is, the condition numbers of the matrix resulting upon discretizing the equation rise with the mesh density. The electric field integral equation, often used to model scattering by perfect electrically conducting bodies, is susceptible to a similar breakdown phenomenon. Recently, this breakdown was cured by leveraging the Calderón identities. In this paper, a Calderón preconditioned PMCHWT integral equation is introduced. By constructing a Calderón identity for the PMCHWT operator, it is shown that the new equation does not suffer from dense discretization breakdown. A consistent discretization scheme involving both Rao-Wilton-Glisson and Buffa-Christiansen functions is introduced. This scheme amounts to the application of a multiplicative matrix preconditioner to the classical PMCHWT system, and therefore is compatible with existing boundary element codes and acceleration schemes. The efficiency and accuracy of the algorithm are corroborated by numerical examples. [ABSTRACT FROM AUTHOR]

Modeling the combined electromagnetic (EM)/quantum transport problem in graphene circuits requires the development of novel concepts and novel unified tools. In this paper, we further explore the correlation between Dirac and Maxwell equations, in the time domain, where we derive the transmission-line equations, valid for both EM and quantum current. This is a step forward toward an effective integration of the Dirac theory in the numerical simulation of EM field problems and introducing EM concepts and simulators to describe quantum transport. We show that the familiar Telegrapher's equations can be readapted in order to investigate the mechanisms that govern the space–time evolution of Dirac spinors; two significant examples, having a double quantum/EM meaning, are provided. Final considerations about associated quantum current have also been reported. [ABSTRACT FROM AUTHOR]

This paper develops a parallel fast multipole method specialized for uniform brick elements to achieve large-scale micromagnetic simulations of a practical perpendicular recording head within acceptable computation time. In highly parallel computation, it is indispensable to equally distribute the computing load among processes so as to obtain the good parallel speedup. The load balancing technique which can be regarded as the domain decomposition method based on octree structure in the fast multipole method is discussed. The scalability of the parallel fast multipole accelerated micromagnetic simulation is investigated with 100 or more MPI processes. [ABSTRACT FROM AUTHOR]

This paper deals with the dynamic characteristics of a linear induction motor (LIM) in terms of acceleration times and jerk conditions. We employed Matlab Simulink for conducting simulations of the dynamic modeling of LIM operated by a space vector pulse width modulation inverter. From the simulation results, the maximum load conditions and minimum acceleration times to guarantee passengers' safety were determined. Further, the electromagnetic field theory was employed to derive equivalent circuit parameters, and the results were validated by the finite element method. The analysis model was applied to a magnetic levitation vehicle for providing electromagnetic propulsion force, and its dynamic characteristics were analyzed to predict its operating performance; moreover, experimental results were employed to demonstrate the validity. We believe that the proposed prediction technique for the operating characteristics of LIMs can contribute to improving passengers' safety and riding quality. [ABSTRACT FROM AUTHOR]

This paper deals with the magnet pole shape design of permanent magnet machines for the minimization of torque ripple based on electromagnetic field theory. On the basis of a magnetic vector potential and a two-dimensional (2-D) polar system, analytical solutions for flux density due to permanent magnet (PM) and current are obtained. In particular, the analytical solutions for mathematical expressions of magnets with different circumferential thicknesses can be solved by introducing improved magnetization modeling techniques, resulting in accurate calculations of electromagnetic torque. The analytical results are validated extensively by nonlinear finite element method (FEM). Test results such as back-emf measurements are also given to confirm the analyses. Finally, on the basis of derived analytical solutions, a reduction of torque ripple can be achieved. [ABSTRACT FROM AUTHOR]

Cellular phones are used in the vicinity of the human head, resulting in localized exposure to this part of the body. To simulate exposure during cellular phone use, microwave energy absorption should be focused within the head region of laboratory animals. In this paper, we developed an exposure system using a figure-8 loop antenna to permit localized exposure of a rat head to 1500-MHz microwave fields, simulating human head exposure to cellular phones. We have numerically estimated the specific absorption rate (SAR) in a rat exposed to microwave fields via our new exposure system. The high ratio of SAR averaged over the target tissue (i.e., the brain) to that averaged over the whole body suggests that the figure-8 antenna can realize greater localized exposure than the previously used exposure system. We have also confirmed the effectiveness of our proposed system experimentally. [ABSTRACT FROM AUTHOR]

The hardware commissioning of the Large Hadron Collider required the testing and the qualification of the cryogenic and vacuum system, as well as the electrical systems for the powering of more than 10 000 superconducting magnets. Nonconformities had to be resolved within a tight schedule. In this paper, we focus on the role that electromagnetic-field computation has played during hardware commissioning in terms of the analysis of a magnet quench and electromagnetic-force calculations in busbars and splices, as well as field-quality prediction for the optimization of powering cycles. [ABSTRACT FROM AUTHOR]

This paper introduces an approach which enables very large power systems to be modeled on real-time electro-magnetic transients (EMT) digital simulators. This is achieved using an improved wide-band multi-port equivalent, which reduces a large power network into a small manageable equivalent model that preserves wide-band behaviors. The low-frequency or electromechanical transients are captured with a transient stability analysis (TSA) type electromechanical equivalent derived using coherency-based reduction techniques. The high-frequency behavior is accurately captured by placing in parallel with the TSA equivalent, a passive frequency dependant network equivalent (FDNE). The validity of the proposed technique is demonstrated by comparing the approach with detailed electromagnetic simulations of a modified version of the New England 39-bus test system that includes an HVDC infeed. The power of the method is demonstrated by the real-time electromagnetic transient simulation of a large 2300-bus 139-generator system. [ABSTRACT FROM PUBLISHER]

In this paper, a new approach is presented for determining the substrate parameters of an arbitrary doping profile. It is general, technology independent, nonintrusive, and relies on simple direct-current measurements. A single measurement is required for uniform substrates, whereas two more measurements are needed for each additional layer in the multilayer case. Two different kernels are introduced for substrate resistance computation. One features a closed-form analytical solution of the Laplace equations defining the problem under study. The other relies on a geometric formulation of the current streamlines in order to compute the substrate resistance. Both simulations and measurements are exploited in order to show the validity of the proposed scheme. For measurements, data from literature are utilized and also data from a fabricated test chip. The results demonstrate that the proposed method succeeds in computing the substrate parameters fast and with high accuracy. In uniform substrates, the error falls to zero, whereas, in epitaxial substrates, the average error is kept bellow 4%. [ABSTRACT FROM AUTHOR]

An efficient time-domain discrete model of the interaction of an electron beam with an electromagnetic wave propagating in a slow-wave structure has been described by Kuznetsov. Using a projection of Maxwell's equations onto the eigenmodes of the structure, the evolution of the entire electromagnetic field can be reduced to the evolution of its amplitude alone in each period of the waveguide. The number of degrees of freedom of the system is thus greatly reduced. This model has been successfully applied in the case of coupled-cavity traveling-wave tubes (TWTs) and can be applied to klystrons, where the circuit field is localized between the gaps of the cavities. In this paper, we present the results of numerical simulations performed by applying this model to a helix TWT. We show that the results obtained are in very good agreement with theory. We also compare our results with those from frequency-domain TWT simulation software. [ABSTRACT FROM PUBLISHER]

Overlapping elements can be used to connect non-conforming meshes in the finite-element method. This approach has been developed with the scalar potential formulation and used to solve magnetostatic problems but not in the case of the vector potential formulation. In this paper, we propose to introduce the overlapping element method in this second formulation. [ABSTRACT FROM PUBLISHER]

Flaw profile characterization from nondestructive evaluation (NDE) measurements is a typical inverse problem. A novel transformation of this inverse problem into a tracking problem and subsequent application of a sequential Monte Carlo method called particle filtering has been proposed by the authors in an earlier publication. In this paper, the problem of flaw characterization from multisensor data is considered. The NDE inverse problem is posed as a statistical inverse problem, and particle filtering is modified to handle data from multiple measurement modes. The measurement modes are assumed to be independent of each other with principal component analysis used to legitimize the assumption of independence. The proposed particle-filter-based data fusion algorithm is applied to experimental low-frequency NDE data to investigate its feasibility. [ABSTRACT FROM AUTHOR]

Protection elements are commonly used in electronic systems: digital integrated circuits (ICs) include built-in electrostatic discharge protection devices, and sensitive lines or printed circuit boards traces are often protected using discrete elements, such as clamping or Zener diodes. In order to know if a perturbation is able to disturb or damage ICs, the actual level of signal entering the digital core of the components must be accurately determined, taking into account all the effects of the protection devices. Thus, assessing the perturbation signal at IC core level requires accurate models of the protection elements, even in the case they are inactive. Therefore, this paper focuses on the experimental and theoretical evaluation of the protective behaviors and parasitic effects of these elements. Some limitations of the standard SPICE diode and IBIS models are discussed, and a modeling methodology is presented. Based on a time-domain characterization method associated with a parameter-extraction procedure for enhanced SPICE diode models, the methodology is applied to both discrete and on-chip protection devices and has a good agreement with measurement. [ABSTRACT FROM PUBLISHER]

In this paper, a general domain expression is developed to calculate the horizontal electric field at the ground surface. The expression satisfies stricter conditions than the Cooray–Rubinstein (C-R) and Wait formulae. We proved that the new expression can be reduced into the first approximation of the C-R and Wait formulae. An evaluation that utilized the numerical results obtained by the three formulae was conducted to investigate the error caused by the assumptions made in the C-R and Wait formulae. Finally, the approximate method proposed by Caligaris, Delfino, and Procopio was utilized to evaluate the new formula and the C-R formula through comparison with the results obtained conventionally using the C-R formula. [ABSTRACT FROM PUBLISHER]

A new method for the numerical simulation of the stochastic electromagnetic environment of a mode-stirred chamber is presented in this paper. This method is based on the plane-wave integral representation for the fields and uses a Monte Carlo simulation to replace the analytical integration by numerical summation. Therefore, a field generator is implemented as a program. The numerically generated field distributions and spatial correlation functions are compared to the analytical solutions for the validation of the field generator. With this generator, the field coupling to a simple transmission-line structure can be numerically simulated. The coupled current or voltage has to be regarded as a stochastic value as well, and therefore, parameters like the mean value and the standard deviation along the line are calculated. For the special case of a matched line, an analytic solution is introduced in order to validate the numerical results. The simulation also allows for investigating the statistical distribution and correlation of the coupled current along the transmission line. Numerous simulated results are compared with measurements. [ABSTRACT FROM PUBLISHER]