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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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

This paper presents copper and iron loss models of a classical switched reluctance motor (SRM) and a mutually coupled switched reluctance motor (MCSRM). The iron losses in different parts of machines are then detailed. Based on the power losses model, a lumped parameter (LP) transient thermal model during driving cycles is performed, the analytical results are validated by the finite-element (FE) transient thermal model. Special attention has been paid to model the salient rotor and a method to transform the salient rotor into a nonsalient one has been proposed. A comparison between the maximum temperatures obtained by using different heat source (average power losses or instantaneous power losses during driving cycles) is given. The experimental tests are also realized to verify the analytical and numerical results. [ABSTRACT FROM PUBLISHER]

This paper concerns the modeling of electromagnetic vibration-and-noise sources in permanent-magnet direct current (PMDC) commutator motors. The electromagnetic sources are considered as an electromagnetic field distributed in the air-gap region of a PMDC motor. The latter is then formulated by the two-dimensional field theory in polar coordinates with the consideration of slotting effects and the armature reaction field. Consequently, based on the derived radial electromagnetic field, the radial and tangential magnetic forces acting on the inner surface of the permanent magnets can be expressed as Fourier functions in forms of space and frequency harmonics. The results obtained from the present models agree well with those from the finite-element models. In addition, the measured cogging torque is compared to those calculated by the analytical and finite-element models to validate the formulated electromagnetic field and magnetic forces. Furthermore, experimental investigations are carried out on the electromagnetic vibration-and-noise behavior of a commonly used PMDC commutator motor (such as that in heating, ventilating, and air conditioning (HVAC) systems). By measuring the natural frequencies and the associated mode shapes of the stator, the relationships between the magnetic forces and the measured vibration-and-noise responses are discussed in the frequency domain. [ABSTRACT FROM PUBLISHER]

This paper involves the computation of 3-D magnetic fields in high-performance, long-lifetime solenoid actuators by finite-element (FE) modeling. Operating at frequencies between 150 and 300 Hz, these actuators are unique in terms of the large force they produce (8–15 N) and their very long lifetime (over five billion continuous duty cycles). Their magnetic circuit typically operates at saturation and, because of the compact dimensions, the 3-D nature of the field distribution needs to be taken into account for their design. Results are presented in terms of the effects of design parameters on saturation and force calculation. [ABSTRACT FROM AUTHOR]