bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct torque control of switched reluctance motor for minimizing torque ripple
Authors: Kim Youn-Hyun , Kim Sol , Choi Jae-Hak , Ahn Joonseon , Cho Chang-Hyun , Lee Ju
Published: December 2018

Large torque ripple of the Switched Reluctance Motor (SRM) is a major problem that is an obstacle to spreading over an industry. Nonlinear inductance profile and pulse magnetizing make the torque ripple unavoidable. In order to reduce the torque ripple, it is necessary to control the torque directly because the torque of the SRM is not linearly proportional to a current. This paper shows direct torque control scheme that reduces the torque ripple of the SRM dramatically. To verify the feasibility of control scheme, simulation and experiment are carried out.
Speed estimation with saliency of synchronous reluctance motor
Authors: Ahn Joonseon , Choi Jae-Hak , Go Sung Chul , Kim Sol , Kim Yun-Hyun , Choi Jae-Hoon , Lee Ju
Published: December 2018

This paper presents a sensorless algorithm of the synchronous reluctance motor(SynRM). Conventionally flux estimation method using phase voltage integration has problem in low speed operation. This is due to insufficient terminal voltage in that speed. However in high speed operation, it is enough to estimate rotor flux. Therefore in this paper the current model which uses phase current signal is proposed to compensate the insufficiency of terminal voltage in low speed to estimate rotor position. Computer simulations are performed to confirm the adequacy of the proposed control scheme. The experiments are also performed for verification of proposed algorithm.
A statistical image fusion algorithm for NDE applications
Authors: Kumar Mrityunjay , Ramuhalli Pradeep
Published: December 2018

Data fusion techniques have been used extensively in several application areas, including nondestructive evaluation (NDE) applications. This paper proposes a probability density based pixel-level fusion algorithm for NDE applications. The proposed approach models the fusion process as a convex combination of input data. The model parameters are estimated by optimizing the Kullback-Leibler distance between the density functions of the fused and the input data. Preliminary results on multimodal eddy current NDE data from aircraft lap joints indicate the feasibility of the proposed approach.
Prove the ability of microwave nondestructive method combined with signal processing to determine the position of a circumferential crack in pipes
Authors: Abbasi K. , Ito S. , Hashizume H.
Published: December 2018

This paper presents a technique using microwaves nondestructive testing to detect circumferential crack and its location in stainless steels pipe. This approach is based on the surface current flow in the inner surface of the test pipe, when electromagnetic (EM) waves are propagating inside the pipe. Since the conductive pipe is an excellent waveguide, EM-wave can be propagated inside the pipe above the cutoff frequencies in large distances. To detect circumferential crack in pipes, a suitable EM-wave mode is generated in the inspected pipe with crack. For this purpose, a mode-converter is used to convert rectangular TE _{10} -mode to the circular TM _{01} -mode. This mode is controlled and resonated by a moving a plunger mounted in the mode-converter. To show the crack existence from experimental data, the background signal of a pipe without a crack is subtracted from that one with a crack. The location of the crack is found by knowing the time of flight (TOF) of the reflected waves and the group velocities of the waves in each part of the waveguides used in this study. The TOFs are obtained through an analysis based on the Inverse Fast Fourier Transform (IFFT) of the signals in the frequency domain and a method of signal cancellation. The obtained results show that this NDT method is suitable for determining of crack locations in large pipes without point-by-point screening since electromagnetic waves above their cutoff frequencies can propagate in pipes without significant attenuation loss. Our study is of a fundamental interest in nuclear power plants and piping systems.
Magnetoelectric effects in laminated multiferroic shells
Authors: Zhang C.L. , Yang J.S. , Chen W.Q.
Published: December 2018

Two-dimensional equations for laminated multiferroic shells of piezoelectric and piezomagnetic layers are obtained from the exact three-dimensional equations. Mechanically, the two-dimensional equations represent the so-called first-order theory that describes coupled extensional, flexural and thickness-shear motions. The electric and magnetic fields are described layer by layer. The two-dimensional equations obtained are used to study magnetoelectric coupling in a laminated multiferroic circular cylindrical shell. Both static coupling and the frequency dependence of the coupling in time-harmonic motions are examined.
Inverse problem solution algorithms in magnetocardiography: New analytical approaches and some results
Authors: Primin M. , Nedayvoda I.
Published: December 2018

This paper describes the development of the magnetostatic inverse problem solution methods for studies of the magnetic field of human heart(magnetocardiography – MCG). A set of N different dipole sources is associated with the spatial distribution of the heart magnetic field parameters, measured in the observation plane.

Methods: Estimation of the field sources quantity in the heart for a given time-point of the average cardiocycle is obtained after spatial-and-time analysis of the spatial gradients intensity of the magnetic field in the observation area (plane). Relative powers of the field sources have been obtained by plotting the Voronoi diagram. Mutual locations(coordinates) of the sources in the heart volume are obtained after examining the analytical solution of the magnetostatic inverse problem for each of the N magnetic dipoles.

Results: The analytical solution of the magnetostatic inverse problem for several magnetic field sources, independently distributed in a 3D volume, has been obtained. The validity of the problem solution is supported by the results of numerical and physical simulations.

Conclusions: Algorithm of the magnetostatic inverse problem solution is implemented as a software package for the magnetocardiograph and used for cardiology diagnosis.
Optimal design of interior-permanent magnet synchronous machine for vehicle using improved niching genetic algorithm
Authors: Seo Jang-Ho , Kwak Sang-Yeop , Chung Tae Kyung , Jung Sang-Yong , Jung Hyun-Kyo
Published: December 2018

In this paper, an improved niching genetic algorithm applying the concept of auto-tuning and detecting traces is proposed for asymmetrical multimodal function optimization. Population size and both (right and left) niche radii of each peak in an asymmetrical objective function can be determined automatically. This method is applied to the numerical examples and the optimal design of interior permanent magnet synchronous machine (IPMSM). Through the comparison between simulation results and experimental ones, the validity of the proposed method is verified.
The constitutive equations of half coated metal core piezoelectric fiber
Authors: Bian Yixiang , Qiu Jinhao , Wang Xinwei , Ji Hongli , Zhu Kongjun
Published: December 2018

The half coated metal core piezoelectric fiber (HMPF) is one of the new type piezoelectric devices for sensors and actuators. The constitutive equations of cantilevered HMPFs under various mechanical and electrical loading conditions are derived. The equations can describe the behavior of HMPF subjected to an external voltage V on the electrodes, a bending moment M at the free end of the beam, a lateral force F at the tip of the beam and a uniformly distributed load p on the whole length.

The internal energy density of the beam is expressed in mechanical strain and electrical field. The internal energy is calculated by integrating the energy density over the whole volume of the beam. The voltage V, bending moment M, lateral force F, and distributed load p are generalized force acting on the fiber and their corresponding generalized displacement are the charge Q on the electrodes, the tip angleα, the tip deflection δ, the areal displacement A of the fiber.

The constitutive equations give the dependence of the generalized displacements upon generalized forces. The equations are given in the direct form, with external parameters (M, V),(F, V), and (p, V) as independent variables and also in a linear combination with (M, F, p, V) as variables. The constitutive equations derived in this paper can be used for further analysis of HMPF sensors and actuators.

Two experiments, in which a HMPF was used as a sensor or an actuator, were performed to verify the constitutive equations. The experimental results are compared with the numerical results.
Conductor loss calculation of elliptical, cylindrical coplanar waveguides and coplanar waveguides with finite conductor thickness
Authors: Duyar Mehmet , Akan Volkan , Yazgan Erdem , Bayrak Mehmet
Published: December 2018

In this paper, new and fast analytical formulations have been presented for conductor loss calculations of elliptical (ECPW) and cylindrical coplanar waveguide (CCPW) with finite conductor thickness. These expressions are derived using conformal mapping techniques (CMT) and the validity of them is established by comparing the numerical results in the literature. These comparisons indicate that for the same conductor thickness the conductor losses of elliptical and cylindrical coplanar waveguide are higher than the conductor losses of coplanar waveguide presented in [1]. Calculation method developed in this study is an extension of the approximate technique proposed by Ghione [1].
Theory of operation of direct string magnetic gradiometer with proportional and integral feedback
Authors: Veryaskin Alexey V.
Published: December 2018

A quantitative theory of operation of a novel device, namely Direct String Magnetic Gradiometer (DSMG), is presented. The paper provides a detailed analysis of DSMG basic functions and measured quantities, represented in terms of physical parameters that are known either a priori or can be experimentally determined. It leaves a reasonable degree of freedom to further investigate some of the finer detail of this new instrument based on experimental results coming both from the laboratory environment and from field trials. The analysis also allows us to quantitatively evaluate the error budget for an optimised DSMG.
Topology optimization of a piezoelectric-mechanical actuator with single- and multiple-frequency excitation
Authors: Wein Fabian , Kaltenbacher Manfred , Bänsch Eberhard , Leugering Günter , Schury Fabian
Published: December 2018

We present the topology optimization of an assembly consisting of a piezoelectric layer attached to a plate with support. The optimization domain is the piezoelectric layer. Using the SIMP (Solid Isotropic Material with Penalization) method with forced vibrations by harmonic electrical excitation, we achieve a maximization of the dynamic displacement. We show that the considered objective function can be used under certain boundary conditions to optimize the sound radiation. The vibrational patterns resulting from the optimization are analysed in comparison with the modes from an eigenvalue analysis. Multiple-frequency optimization is achieved by adaptive weighted sums. As a second optimization criterion, a flat frequency response is integrated in the optimization process.
Adaptive sampling technique based on moving meshes for building data-equidistant inversion databases for NDT
Authors: Gyimóthy Szabolcs , Kiss Imre , Pávó József
Published: December 2018

An adaptive sampling method based on simplex-mesh refinement is proposed for creating a database that facilitates the inverse problem solution in NDT. The resulting database is used as a generic interpolator of the forward problem. In order to obtain optimal sampling for the purpose of interpolation, physically based mesh generation technique relying on spring analogy is utilized. The method is tested with a four-parameter crack reconstruction problem. It is demonstrated that the optimized database provides high interpolation quality comparing to regular grid databases.
Fabrication of lead-free barium titanate piezoelectric ceramics from barium titanate powders with different particle sizes synthesized by hydrothermal method
Authors: Zhu Kongjun , Qiu Jinhao , Ji Hongli , Totsuka Atsushi
Published: December 2018

In this study, three types of BaTiO _{3} powders with different particle sizes synthesized by hydrothermal method were used to fabricate the lead-free barium titanate piezoelectric ceramics. The BaTiO _{3} ceramics from these three types of BaTiO _{3} powders were sintered at different temperature(1150–1350°C) using traditional sintering method, and their piezoelectric properties were investigated and compared. The results indicate that the BaTiO _{3} piezoelectric ceramics from BT03 powder exhibit highest d_{33} value (over 350 pC/N). The reasons were also investigated by comparing the properties of three kinds of BaTiO _{3} powders and their compacts sintered at different temperature.
Effective electric and magnetic properties of the infinite chain of circular metallic cylinders
Authors: Rybin Oleg , Raza Muhammad
Published: December 2018

In this paper we investigate the electric and magnetic responses from the infinite chain of infinite circular metallic cylinders periodically imbedded with dielectric matrix. The long-wavelength approximation for the complex effective dielectric and magnetic constants is obtained on base of the Effective Medium Theory. Comparisons of the analytically obtained results with the numerically calculated ones are made. Conclusions about applicability range of the proposed analytical model have been made.
Some studies on the electromagnetic aspects governing the magnetically impelled arcs through experimentation, finite element simulation and statistical analysis
Authors: Vendan S. Arungalai , Manoharan S. , Buvanashekaran G. , Nagamani C.
Published: December 2018

In this study, Magnetically Impelled Arc Butt welding (MIAB) laboratory setup for welding carbon steel tubes of small wall thickness is designed and developed. Magnetically Impelled Arc Butt welding is an efficient two phase process which is used in highly automated factory production lines in high volume industries such as automotive manufactures. In this process, an electric arc generated between aligned and properly gapped pipes are made to rotate along the peripheral butt ends. This arc swiftly rotates along the peripheral edges of the tubes to be welded due to the electromagnetic force resulting from the interaction of the arc current and the externally controlled magnetic field created by magnetic systems. The arc acts as a heating source providing the required heat to the butt ends of the pipes. Further an application of force on the pipe along the axial direction sets the weld. The electromagnetic force responsible for the arc rotation is governed by the magnetic flux density in the gap, the arc current and the arc length (gap size). To be precise the radial magnetic flux density is a critical factor in arc rotation and weld quality. Preliminary trials are conducted to understand the process parameters. Tubes with 45 mm Outer Diameter with 3 mm thickness are used for conducting the investigations. Further, for the first time an attempt is made to analyze the effects of weld input parameters such as welding current, welding voltage, magnetic coil voltage and magnetic coil current on the arc speed in MIAB welding process using software package STATA. The aim of this study also is to explore the distribution of the magnetic flux density in the tube gap region using finite element code ANSYS .The analysis emphasizes that the most significant factor that governs the arc speed is magnetic coil current (that creates magnetic flux density) and the welding current.
A semi-passive vibration damping system powered by harvested energy
Authors: Shen Hui , Ji Hongli , Qiu Jinhao , Zhu Kongjun
Published: December 2018

This paper designs and investigates a vibration damping system powered by harvested energy with the implement of the so-called SSD(Synchronized Switch Damping) technique, which is a semi-passive approach. In the semi-passive approach, the piezoelectric element is switched from open circuit to closed circuit synchronously with the structure motion. Due to this switching procedure, a phase shift induced between the strain of vibration and the resulting voltage, thus creating energy dissipation. A low-power version of the switching circuit for nonlinear processing of voltage has been designed, and by combining the switching circuit with an energy harvesting subsystem, a semi-passive vibration damping system without external power supply has been successfully developed. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results.
Numerical computation of inductance of complex coil systems
Authors: Im Chang-Hwan , Jung Hyun-Kyo
Published: December 2018

In this paper, inductance of complex coil systems is calculated using 3-D finite element analysis (FEA) with a new flux linkage calculation technique. The proposed technique does not require any integral path if current direction in a coil is determined, because the flux linkage is calculated based on the simple volume integration. Moreover, it can consider inconsistent coil cross-sectional areas. The technique is verified by the application to a manufactured deflection yoke (DY) coil. By the comparison with an experimental result, it is shown that the proposed technique is accurate and effective in calculating inductance of complex coil systems such as a DY.
Stabilizing the E-Field Integral Equation at the internal resonances through the computation of its numerical null space
Authors: Angiulli G. , Tringali S.
Published: December 2018

In this paper a technique to protect the Method of Moments solution of the E-Field Integral Equation (EFIE) for the scattering by conducting body from effects of its internal resonances, is presented. This method is based on the evaluation of the numerical null space K of the discretized EFIE operator. In order to verify its effectiveness, results for the plane wave scattering from a perfect conducting cube are presented. It is shown that the proposed method is able to give the correct value of the RCS even in presence of the interior resonances.
A design electromagnetic system of surface finishing processes
Authors: Pa P.S.
Published: December 2018

An intelligent design system was created that efficiently uses a magnetic force to assist in the discharge of the dregs from the electrode gap during electrochemical finishing of cylindrical surfaces. In the current experiment, the author used a cylinder-shape electrode supplied with a continuous and pulsed direct current in the electrochemical finishing. This study used Taguchi's Method to analyze the combination of optimal parameters. The experimental parameters use four factors and three levels to measure the surface roughness of the magnetic-assistance in the electrochemical finishing. These four factors include electric current density, magnetic strength, distance between the two magnets, and rotational speed. For the design system, a high electric current density coupled with electromagnetic-assistance reduces the finishing time and mitigates the issues associated with dreg discharge. A small distance between two electromagnets or a large electromagnetic field produces a larger electromagnetic force enhancing the dreg discharge and subsequently improves the finish. A small tool-electrode diameter enhances electromagnetic-assisted electrochemical finishing. The average effect of the magnetic assistance was greater than the pulsed current while the machining time did not need to be prolonged by the off-time.
A computer model of the annihilation of the electric field in an electromagnetic wave by the elastic stress field of a rotated grain
Authors: Andy A.U. , Abayomi A.T. , Kennefick C.M.
Published: December 2018

Resistance to heat was simulated and measured in a computer model as an annihilation of the elastic stress arising from the electric field in the radiation. The elastic stress created from the electromagnetic wave was superimposed with the elastic stresses produced by the rotation of a grain, which was represented in two dimensions as an ellipse in the simulation. Both the tilt angle of the grain with respect to the applied force and the aspect ratio of the grain were varied in the computer program. Results are reported here for a ratio of wavelength to total grain length of 10. Annihilation of an elastic stress from the electric field of up to 80 to 90 percent was seen for aspect ratios of 8/7 to 2 in several ranges of grain tilt angle. For this same range in aspect ratio, steep transitions in the amount of annihilation were seen near the ends of the grain. An elongated grain, with an aspect ratio of 10 and rotating counterclockwise, exhibited extinction of 50 to nearly 90 percent of the electric field near the lower end of the grain throughout the tilt angle range of 5° to 85°.
Development of improved memory architecture FDTD/FIT dedicated computer based on SDRAM for large scale microwave simulation
Authors: Fujita Yuya , Kawaguchi Hideki
Published: December 2018

Authors have been working in devlopment of the Finite Difference Time Domain (FDTD) / the Finite Integration Technique (FIT) dedicated computer for high performance computation of microwave simulation. Especially the dedicated computer with optimized memory access architecture was proposed to reduce overhead of Neuman bottleneck in FDTD calculation. Based on the optimized memory architecture, dedicated computer was implemented on fully customized Printed Circuit Board (PCB) by using the Field Programable Gate Array (FPGA) and asynchronous Static Random Access Memory (SRAM). This paper presents a newly developed FDTD/FIT dedicated computer based on Synchronous Dynamic Random Access Memory (SDRAM) for larger scale and higher performance simulation.
Long wave layer-specific representation of the optical properties of slab metamaterials
Authors: Rybin Oleg , Raza Muhammad
Published: December 2018

Analytical and numerical optimization method for evaluating the complex effective dielectric and magnetic constants of elementary flat slab of metamaterial is presented. The minimization problem is solved for a cascaded network representation of the slab utilizing the Effective Medium Theory. The algorithm is benchmarked using the free Meep FDTD software package.
Design of Yagi-Uda array using Particle Swarm Optimization
Authors: Rattan Munish , Patterh Manjeet Singh , Sohi B.S.
Published: December 2018

The optimization of Yagi-Uda antenna is a subject of continuous research since its invention because of its multimodal pattern and complexity due to the presence of parasitic elements. Particle Swarm Optimization (PSO) is a new, high performance evolutionary technique, which has recently been used for optimization problems in antennas and electromagnetics. In this paper, PSO has been used to simultaneously optimize the gain, front-to-back ratio, input resistance and beamwidth of Yagi-Uda array. The antenna array geometry with good performance, compared to the results in available literature, has been obtained.
Simulation and verification of the axial force of a linear permanent magnet synchronous actuator
Authors: Al-Sharif Lutfi , Taifour Sinan , Kilani Mohammad
Published: December 2018

A methodology has been developed for the simulation and experimental verification of the axial force exerted by an electromagnet on a concentric permanent magnet. This comprises four stages. The first involves the modeling of the permanent magnet as a current sheet based on the permanent magnet material and its dimensions. This current sheet model is then discretised into a number of coils. The second stage involves the prediction of the radial magnetic flux density from the electromagnet at any point off its axis. The third stage involves the calculation of the axial force exerted by the electromagnet onto a concentric current carrying ring along its axis. The fourth stage involves the calculation of the axial force exerted by the electromagnet onto a number of contiguous rings that represent the model of the permanent magnet developed in the first stage.

Experimental verification has been carried out for the fourth stage by the measurement of the resultant force by the use of weights. The method was implemented in matlab for all the four stages. In addition to the experimental verification, PC based verification was also carried out against a FEM software for the results from all the four stages.
Development of a three-dimensional tactile sensor for minimally invasive instruments
Authors: Takanashi Hiroyuki , Tanaka Mami , Tanahashi Yoshikatsu , Chonan Seiji
Published: December 2018

This paper proposes a three-dimensional tactile sensor that can be attached to the tip of an endoscope or catheter to detect the tip contact conditions. Because conventional minimally invasive instruments (MIIs) without a sensor cannot detect the posture and applied force at the tip, operators cannot obtain accurate information during minimally invasive surgery (MIS). The sensor consists of an elastic cylinder and three strain gauges. The gauges, located on the surface of the cylinder at intervals of 120°, are used to detect deformation of the cylinder caused by contact with the inner walls of the patient's organs. The output voltage signals of the gauges are approximated by a sinusoidal function with a phase difference of 120°. The three-dimensional contact angle and applied force at the tip of the sensor can be estimated accurately from the three sinusoidal functions and measured output voltage signal from the gauges. The operating principle of the sensor is examined through several experimental conditions.
Enhanced construction of the direct radiator electrodynamic loudspeaker
Authors: Merit B. , Remy M. , Lemarquand G. , Lemarquand V.
Published: December 2018

This paper first presents the principle of the electrodynamic loudspeaker. It particularly shows how few evolutions occurred since the first device was designed. Then, it describes the loudspeaker drawbacks whose sources lie in the motor – especially because of the iron-, the moving part and the suspension. Furthermore, the major goal of this paper is to propose examples of evolutions which suppress some of the drawbacks. So, the motors presented are ironless, made with permanent magnets only. Their structure can be optimized to create very uniform magnetic fields in the air gap where a short coil is totally submitted to the field. Moreover, the elastomer suspensions are replaced by ferrofluid seals which guide the moving part. Besides, the moving part itself becomes a lightweight rigid bulk piston. Eventually, these proposals prove that evolution of the electrodynamic loudspeaker is still possible. And the possibilities are of course myriads.
The refined theory of magnetoelastic beams for tension and compression deformation
Authors: Gao Yang
Published: December 2018

Without employing ad hoc assumptions, various equations and solutions for magnetoelastic beams are deduced systematically and directly from the two-dimensional magnetoelasticity. These equations and solutions can be used to construct the refined theory of magnetoelastic beams for tension and compression deformation. By using the general solution for the soft ferromagnetic elastic solids and the Lur'e method, the refined theory can now be explicitly established. In the case of homogeneous boundary conditions, the exact governing differential equations and solutions for beams are derived, which consist of three governing differential equations. In the case of non-homogeneous boundary conditions, a traction free boundary condition is considered. In two illustrative examples of beams, it is shown that the exact or accurate solutions can be obtained in use of the refined theory deduced herein.
Release control of drug-encapsulated liposomes by piezoelectric ultrasonic probe
Authors: Jiang Zhongwei , Chen Guoming , Kawazu Takaaki , Morita Minoru
Published: December 2018

Liposomes as a drug delivery system have been an attracting interest to many researchers. This paper concerns with the study on how to control the release rate of the inner-substances from liposomes by the ultrasonic irradiation. Two kinds of ultrasonic control methods are tested for investigation of the efficiency of the release property of the liposomes. One control method is to increase the input power by fixing its frequency at a frequency near the probe resonant frequencies. Another method is to adjust the input frequency around the probe resonant frequencies but fixing the input power. In the experiments, three kinds of liposomes with different lipid ratio were prepared and calcein as an indicator was enclosed into the liposomes. The release effect was evaluated from the fluorescence intensity changes which was measured by a spectrofluorometer. The results showed that the efficient release property could be achieved both by control of the input power and the input frequency, but adjusting the input frequency around the probe resonant frequency can get higher efficient release performance than that controlled by the input power.
Comparative EGUN and TRAK simulation studies on the design of the magnetron injection gun of a 200kW, 42GHz gyrotron
Authors: Singh Udaybir , Kumar Narendra , Kumar Nitin , Bera A. , Purohit L.P. , Sinha A.K.
Published: December 2018

A triode-type magnetron injection gun (MIG) for a 42 GHz, 200 kW gyrotron was designed by two commercial codes: EGUN and TRAK. An in-house code MIGANS was used as the post-processor of the EGUN. Some basic equations relevant to the problem available in literature were used while using the EGUN code for the purpose. The results on the design output parameters obtained by these two codes were found to be in close agreement.
Research and multi-physical fields analyses of rare earth permanent magnet electrical machines in China
Authors: Tang Renyuan , Han Xueyan , Zhou Ting
Published: December 2018

The status of research and analyses of multiple coupling fields of rare earth permanent magnet electrical machines in China is introduced. Permanent magnet electrical machines with novel structure, Permanent Magnet Wind Power Generators, Permanent Magnet AC Servo Motors and Premium- efficiency Line-Start PMSMs are reported respectively.
The influences of MHD control direction on the hypersonic inlet flow
Authors: Qin Penggao , Chen Zhihua , Sun Xiaohui , Li Baoming
Published: December 2018

Local MHD hypersonic flow control of a scramjet inlet has been conducted in this paper. Two dimensional Euler equations with MHD terms are used for describing the flow filed variations during the control process. An explicit second order Godunov-type scheme is employed to solve the equation, the immersed boundary condition and a block-structured adaptive mesh refinement technique are adopted to handle the complex boundary and high pressure gradient, respectively. Our numerical results show that the MHD control can be used to restore the oblique shock waves at off-design conditions with the force applied at the forebody of the first ramp in proper directions.
Assessing anomalous losses with dynamic hysteresis models
Authors: Mazauric Vincent , Drouineau Mathilde , Rondot Loïc
Published: December 2018

A new approach to face the problem of dynamic hysteresis and assess extra-losses in soft magnetic materials is investigated. Thanks to a spatial averaging technique and a variational principle, a dedicated formulation is derived. It takes into account microscopic magnetization mechanisms and domain wall motion-induced Joule losses. A validation is proposed by assessing time-harmonic losses on a 2D-Pry and Bean iron sheet. Discussion includes also a confrontation with the delayed diffusion model and Bertotti's experiments.
Electrofluid dynamic (EFD) energy conversion in gas flows with suspended nanoparticles
Authors: Machado José Márcio , Shiyou Yang
Published: December 2018

This work presents simulations of the Electrofluid Dynamic energy conversion process in slender channel devices having very small particles (in both micro and nano scales) as charge carriers. Solutions are discussed for a system composed by coupled differential equations, which includes the equation for the total current along the channel, the equations for total energy and momentum of the mixture (gas and solid particles), the continuity equation and the equations for energy and momentum of a single particle. Results for suspended particles of higher diameters have been previously published in the Literature, but the simulations here presented exhibit an appreciable increase in the values for output currents.
Fast calculation and characteristic analysis of array lateral-logging responses
Authors: Dun Yueqin , Tang Zhanghong , Zhang Fang , Zou Jun , Yuan Jiansheng
Published: December 2018

To simplify the calculation of the logging response, a fast approach for simulating the cylindrical electrode only with a point source is presented in this paper. This approach transforms the problem with hollow cylindrical electrodes to that with point sources, which does not only simplify the calculation, but also makes the numerical mode-matching (NMM) method can be employed directly in the calculation. The NMM method is an efficient half-numerical and half-analytical method. By using the approach and the NMM method, a high-efficiency code has been developed and valified. The characteristics between responses and parameters are analyzed, which is crucial to the inversion problem of logging and useful for logging engineers.
Numerical simulation of 3D stray field and short circuit impedance for a phase-shifting rectifier transformer
Authors: Wang Jianmin , Jing Chongyou , Fan Yana , Liu Lanrong , Du Yong , Zhang Junjie , Jiao Cuiping , Cheng Zhiguang
Published: December 2018

The simplified 3D FEM model coupling with the equivalent electric-circuit (EEC) is well established for a phase-shifting rectifier transformer (PSRT). The 3D stray fields, the parallel branch currents and the short-circuit impedances are calculated by the field-circuit coupling method(FCCM). The validity of the proposed analysis method is verified based on real product, which proved to be more efficient for the design of the PSRT.
A self-consistent analysis of subband alignment in a superlattice with one larger well
Authors: Tanaka Roberto Yuji , Passaro Angelo , Abe Nancy Mieko , Vieira Gustavo Soares , Stephany Stephan
Published: December 2018

Self-consistent calculations of multi-quantum well semiconductor structures based on a Finite-Element Method are presented. The self-consistent calculation is specially needed when wells of different width are present in the structure, generating a larger charge separation and affecting significantly the tunneling conditions. The object-oriented computer code used was implemented using a finite-element class library developed and used in previous works. Results for an asymmetric heterostructure with a larger well and contact layers are also presented.
Optimal design of a single-phase induction motor considering magnetically balanced operation
Authors: Choi Myoung-Hyun , Song Jeong-Hyun , Woo Kyungil , Kim Byung-Taek
Published: December 2018

In this paper a design condition for magnetically balanced operation in a single phase induction motor is presented in analytic forms. In addition a condition for minimal stator copper is deduced under condition that the balanced operation is satisfied. Using these conditions, an optimal induction motor is designed by a proper optimization algorithm, and its loss characteristics are investigated. From the results, the validity of the proposed method is verified.
Performance analysis of multiply connected thin shields
Authors: Ciric Ioan R. , Hantila Florea I. , Moraru Augustin , Maricaru Mihai
Published: December 2018

By performing holes in a thin electromagnetic shield, its weight and price can be reduced, without practically changing the shielding efficiency for certain geometries and frequencies. A new method for solving the integral equation of the surface current density in thin shields with holes is applied, where the current density is represented by a linear combination of specialized surface vector functions associated with the interior nodes of the discretization mesh and with the sets of nodes on each hole contour. A Galerkin technique is applied to determine the scalar coefficients of these functions. The magnetic flux density in the shielding zone is obtained accurately, in terms of exact analytical formulas, from these vector functions.
Calculation of electrostatic field in 3-D unbounded non-uniform domains by FEM with kelvin transformation
Authors: Zhang Fang , Tang Zhanghong , Dun Yueqin , Yuan Jiansheng
Published: December 2018

An approach for solving the electrostatic field in 3-D unbounded domains is introduced in this paper, which is the combination of the finite element method (FEM) and the Kelvin transformation. The principle of this method is dividing the whole infinite region into two parts by a spherical surface. In the inner part with a sphere as the boundary, the ordinary finite element method is employed. As for the outer open-boundary part, the approach first transforms it into a finite closed domain that is of the sphere as the boundary, in which the transmuted FEM is used. It is allowed that the exterior open-boundary part is of non-uniform medium, such as unlimited domains or different shapes with different materials whose interfaces might extend to infinity.
A study on magneto-thermal analysis of IPMSM for electrical vehicle with water-cooling system
Authors: Seo Jang-Ho , Jung Hyun-Kyo
Published: December 2018

In this paper, we present a magneto-thermal model of an interior-permanent magnet synchronous machine (IPMSM) for electrical vehicle. Both magnetic and thermal field aspects are described based on 2-D finite element method (FEM). For accurate estimation of heat sources in the machine, we analyzed harmonic iron loss using variable loss coefficients and magnet loss in the electromagnetic field. In addition, we estimated convective exchange coefficient considering water-cooling system of the machine. Finally, experimental results on 60 kW, 3600 rpm are reported and compared with the simulation results.
An energy-based error criterion for eddy current analysis
Authors: Rondot Loïc , Mazauric Vincent , Ladas Dimitrios
Published: December 2018

In order to improve the finite element modeling of macroscopic eddy currents, a quadratic energy-based error criterion is derived from a thermodynamic description of electromagnetism. While the conservation of the electromagnetic power is assessed locally to highlight the ill-checked elements, the state functions provide the global convergence of the calculation within an adaptative procedure. The criterion is shown: suitable for 2D and 3D, independent of the formulation, supporting the body motion. A validation is given on a Thomson's effect device.
A study on the performance simulation of interior permanent magnet synchronous motor for electric vehicle considering nonlinear parameters
Authors: Kim Ki-Chan
Published: December 2018

In this paper, we propose a simulation algorithm for driving characteristics of interior permanent magnet synchronous motor (IPMSM) for electric vehicle considering nonlinear parameters like d-axis and q-axis inductances as well as core loss. D-axis and q-axis inductances as well as core loss parameter are changed according to both current magnitude and current angle between q-axis and current axis because of nonlinearity of magnetic flux density in stator and rotor core. Therefore, the calculation of d-axis and q-axis inductances with nonlinearity of magnetic flux density and core loss is performed by using FEM. We can get precise driving performance of traction motor for electric vehicle adopting nonlinear d-axis and q-axis inductance table and core loss table.
Nonlinear eddy current analysis by BEM for thin plate employing simple iterative approach
Authors: Ishibashi Kazuhisa , Andjelic Zoran , Pusch David
Published: December 2018

Nonlinear eddy currents induced in steel plate are formulated by the boundary integral equations. The integral equations for the nonlinear analysis are derived by regarding nonlinear terms as fictitious sources. As the periodic electromagnetic quantities in the steel plate are distorted, these fields are expressed with the help of Fourier series, whose fundamental and harmonic fields are determined by solving the corresponding integral equations with the surface magnetic fields given as the boundary values. The internal and surface electromagnetic fields are obtained numerically one after the other until convergence. In this iterative solution, Newton-Raphson method has been adopted but it is not applicable if the plate thickness approaches zero. So as to solve the difficulty, we adopt a simple iterative method and have confirmed that the method is effective.
Analysis of complex spatiotemporal behaviors in a time-delayed Chua's circuit
Authors: Zou Jianlong , Chen Feng , Ma Xikui
Published: December 2018

The time-delayed Chua's circuit (TDCC) is an infinite-dimensional electromagnetic system with boundary nonlinearity. An analytic nonlinear model is established for the TDCC. Through simulation, it has been revealed that complex spatiotemporal behaviors characterized by irregular space-time patterns may happen in the TDCC. These complex spatiotemporal behaviors result from the boundary nonlinearity and the space-time coupling. Moreover, it has been found that the initial values during one round-trip delay play an important role in the evolvements of spatiotemporal behaviors at the different locations of the transmission line.
Optimum inducement of eddy current for NDE of deep lying defects: An analytical approach
Authors: Cheng Weiying , Komura Ichiro
Published: December 2018

A line-current model is proposed to calculate eddy current induced by rectangle coils. Eddy current induced by rectangle coils are analytically calculated using this model, and a coil configuration to induce eddy current deeper into a conductive material is proposed. Optimum excitation frequency is also calculated.
Simulation of frequency influence on detection of the inner corrosion for the pipeline
Authors: Ding Keqin , Xin Wei
Published: December 2018

Pulsed eddy current (PEC) detection technology is a new non-destructive testing technology. It can be used to detect the inner corrosion of the low-carbon steel pipeline. The frequency is an important parameter affecting the detection results. In this paper, the influences of frequencies on the detection of inner corrosion are investigated by numerical simulated. By using the method of time-domain difference, the optimization of frequency for detecting the inner corrosion of pipeline is performed. The research results can provide reference for frequency selection in the practical inspection.
Magnetic characteristic analysis and measurement of three-phase generator utilizing grain-oriented silicon steel sheets
Authors: Ishikawa Seiji , Todaka Takashi , Enokizono Masato , Mauchi Chikara
Published: December 2018

This paper presents results of magnetic characteristic analysis of a three-phase generator utilizing grain-oriented silicon steel sheets. In the analysis, the finite element method taking account of the two-dimensional magnetic properties is used to make clear rotational iron loss distributions. In this paper, the knowledge obtained in the numerical simulations by means of the integration-type dynamic E&S modeling is reported. Also, the measurement results of a prototype generator designed with the magnetic characteristic analysis are shown.
Magnetic characteristic analysis of an induction motor model core considering two-dimensional vector magnetic properties
Authors: Kunihiro Naoki , Todaka Takashi , Enokizono Masato
Published: December 2018

This paper presents magnetic characteristic analysis of an induction motor model core considering two-dimensional vector magnetic properties. In order to reduce rotational iron losses, which generate in the stator core, we tried to make holes at the tooth base parts. As a result, the rotational flux distribution was effectively controlled by making holes. The results showed that reduction of the total iron loss might be possible by finding out effective holes' size, shape and position.
Kinetic characteristics of transformer windings under short circuit condition
Authors: Liu Yanqin , Wang Shuhong , Meng Xiangjun , Qiu Jie , Feng Bin , Wei Caixia , Liu Fanghua
Published: December 2018

In this paper, the kinetic characteristics of high voltage power transformer under short-circuit operation are simulated and the influence of prestress is analyzed for the winding stability. Firstly, the finite element method (FEM) is applied to calculate the leakage magnetic field of transformer and electromagnetic force of windings. Secondly, the axial electromagnetic force under short-circuit condition acts on the transformer windings, which are regarded as complex viscoelastic system. The characteristics of the vibration responses, such as dynamic displacement and dynamic force, are illustrated and their frequency responses are analyzed. Finally, the relationship between prestress and peak value of dynamic force, and as well as displacements of each pancake coil, are discussed.
Transient electromagnetic force analysis of high temperature superconducting fault current limiter
Authors: Fang Xu , Qiu Jie , Xiao Hongli , Wang Shuhong , Zhang Jingyin , Gong Weizhi , Xin Ying
Published: December 2018

In this paper, the transient short-circuit current of three-phase saturated core high temperature superconducting (HTS) fault current limiter(FCL) is investigated by using a method of combining 3-Dimensional (3D) finite element analysis (FEA) and equivalent dynamic nonlinear circuit model. The numerical computations are verified by the experiment results on a FCL prototype with rated voltage 380V. Based on the short-circuit current of three-phase saturated core HTS FCL with rated voltage 220 kV, the three-phase transient magnetic field is simulated and analyzed. According to the simulation results, the transient short-circuit electromagnetic forces distribution is obtained.
Coupling plasmas and 3D passive structures in the JET tokamak
Authors: Albanese Raffaele , Artaserse Giovanni , Bellizio Teresa , Rubinacci Guglielmo , Fresa Raffaele , Viola Bruno , Palumbo Maurizio Furno , Villone Fabio , Liu Yueqiang , Contributors JET-EFDA
Published: December 2018

The impact of the 3D effects on the dynamic response of the plasma in the JET tokamak is assessed on the time scale of interest for plasma magnetic control and stabilization. These effects are due to the limbs of the magnetic circuit and to the eddy currents in the 3D metallic structures. The plasma behaviour is taken into account by a specific matrix of modified inductances interacting with the remaining part of the system via a virtual coupling surface.
Conversion of web texts into Braille characters for real time reading through arrays of electromechanical actuators
Authors: Tronco Mário Luiz , Machado José Márcio
Published: December 2018

This paper describes an electronic device conceived to convert common web texts into sequences of corresponding Braille signals, which are immediately reproduced onto an array (keyboard) of electromechanical actuators. These actuators are reconfigurable in real time, displaying the Braille characters as matrices of points composed by small stems which can be lowered or raised according to the Braille code. The device, together with its conversion software package, can provide direct access to web texts in any personal computer, thus avoiding the use of complicated Braille printers.