International Journal of Applied Electromagnetics and Mechanics - Volume 49, issue 4

Authors: Zhou, Yinghui | Huang, Zhengyu | Shi, Lihua | Fu, Shangchen

Article Type: Research Article

Abstract: In this paper, a novel solution based on Associated Hermite polynomials finite-difference time-domain (AH-FDTD) method is proposed to analyze the field-to-transmission line coupling problems. Incorporated with the AH transformation, the method is suitable for dealing with the frequency-domain parameters in transmission line (TL) equations, no convolution integral is involved with. And it is an unconditionally stable scheme, not limited by the Courant condition. Numerical results show that the proposed method is agreeable with the frequency-domain solutions.

Keywords: Associated Hermite polynomials, coupling, FDTD, field-to-transmission line

DOI: 10.3233/JAE-150020

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 443-451, 2015

Authors: Teimouri, Hamid | Afrand, Masoud | Sina, Nima | Karimipour, Arash | Isfahani, Amir Homayoon Meghdadi

Article Type: Research Article

Abstract: In this article, the effect of a radial magnetic field on the steady, laminar and natural convection flow of molten potassium in a long horizontal annulus between two horizontal cylinders is investigated numerically. The inner and outer cylinders are at TH and TC temperatures, respectively, with TH >TC . A finite volume code based on SIMPLER-algorithm is used to solve the governing equations of the model. Simulations are carried out for a wide range of the Rayleigh number (Ra), Hartmann number (Ha) and radii ratio (λ). It is shown that for a given radii ratio as the …strength of magnetic field increases, the convection heat transfer reduces. For narrow annulus, the effect of Hartmann number on the maximum absolute value of the stream function is not eminent compared to the case of high radii ratio. Furthermore it is found that for a given Ha and Ra, the average Nusselt number increases up to about λ = 5 and then reduces gently as λ enhances. Moreover, for all Hartmann numbers the effect of radii ratio on the average Nusselt number has almost the same trend. Show more

Keywords: Liquid metal, radial magnetic field, free convection, horizontal annulus, numerical simulation

DOI: 10.3233/JAE-150028

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 453-461, 2015

Authors: Wei, Tong | Zhao, Lin | Zhao, Lishuang

Article Type: Research Article

Abstract: System identification is an important basis of adaptive control and fault identification of active magnetic bearing (AMB) system. Among all the identification algorithms, least square method (LS) is a comparatively simple one with small calculation amount but a poor performance as well under colored noise, and particle swarm optimization algorithm (PSO) has a good performance under colored noise but a huge calculation amount. Taking advantage of the complementation of LS and PSO, the identification based on LS-PSO algorithm was proposed, which combines the briefness of LS and the high precision of PSO. In the novel algorithm, PSO updates the poles …of identified transfer function model, and LS estimates the numerator optimally. The output error variance is minimized by repeating the procedure. In simulation, the calculation amount declined by 91.4% on average comparing with PSO, and the experiments validated that the error variance of LS-PSO declined by 92.92% relative to LS. The experimental results show that LS-PSO retains high precision of PSO under colored noise, while its calculation amount is greatly reduced by introducing LS, which is significant to practical application. Show more

Keywords: Magnetic bearing, model identification, least square method, particle swarm optimization

DOI: 10.3233/JAE-150025

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 463-473, 2015

Authors: Sun, Hucheng | Zhong, Zheng | Guo, Yong-Xin

Article Type: Research Article

Abstract: This article proposes a compact rectenna for wireless power transmission (WPT) miniaturization applications. A specific rectenna design for powering a wearable optical stimulator is presented. As a critical factor, the required size of the rectenna should be within 1.5 × 1.5 × 1 cm3 . The rectenna is formed by an antenna and a rectifying circuit, which are designed separately and then integrated together. In order to make full use of the limited size, a loop antenna is utilized in this design and the rectifying circuit part is positioned inside the loop. In addition, to further miniaturize the …design, the rectifying circuit is directly matched to the antenna without using of the matching circuit. After fabrication, the rectenna is first linked to a resistive load to test its capability of output DC power. Then, the rectenna is connected to a super-capacitor to store the converted DC power. During the measurements, a standard horn antenna is used to transmit the incident wave to the rectenna. It shows that with proper power input to the transmitting horn antenna, the performed voltage and harvested power of the rectenna can satisfy the design requirements. Show more

Keywords: Wireless power transmission, rectenna, miniaturization, loop antenna, rectifier

DOI: 10.3233/JAE-150031

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 475-482, 2015

Authors: Jang, Sang Dong | Mun, Seongcheol | Min, Seung-Ki | Kim, Hyun Chan | Kim, Jaehwan

Article Type: Research Article

Abstract: Design of rectenna, a key component in wireless power supply, is important for efficient wireless power transmission technology. However, its simulation of rectenna is not so easy because it consists of a microstrip antenna and a rectification circuit, which requires different simulation regimes. In this paper, a coplanar dipole rectenna is simulated by bridging its antenna simulation and rectification circuit simulation. The antenna simulation result is used for the rectification circuit simulation. The simulation results are verified by fabricating and testing the dipole rectenna. Detailed simulation scheme and its experimental verification are explained.

Keywords: Dipole rectenna, coplanar strip antenna, schottky diode, simulation

DOI: 10.3233/JAE150052

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 483-490, 2015

Authors: Fu, Song | Zhang, Yun-Hua | Chen, Xi | Yin, Hong-Cheng | Zhu, Guo-Qiang

Article Type: Research Article

Abstract: A new accurate numerical algorithm is presented for creeping ray tracing on the arbitrarily shaped surfaces modeled by the Non-Uniform Rational B-spline (NURBS) surfaces. The main problem in calculating the uniform geometrical theory of diffraction (UTD) surface diffracted fields on NURBS surfaces lies in the difficulty in determining the geodesic paths which the creeping rays propagate along. In this paper, a novel method is developed based on the property of geodesic to compute geodesic paths on NURBS surfaces. Actually a complex object generally needs to be modeled as a combination of several connected NURBS patches. Therefore a transition method is …presented to handle the transition of the creeping rays when the rays propagate from one patch to another. The proposed creeping ray tracing algorithm is efficient and accurate for ray tracing on arbitrarily shaped complex shapes. And the algorithm can also extend the applicability of UTD for practical engineering. The validity and efficiency of the algorithm is verified by numerical results. Show more

Keywords: Creeping ray, diffraction, NURBS, surface waves, UTD

DOI: 10.3233/JAE-150053

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 491-503, 2015

Authors: Shi, Yan | Peng, Anqi | Jing, Yuan | Xu, Jiajun

Article Type: Research Article

Abstract: This paper presents a novel direct-drive linear compressor for air brake system in electric vehicles. By integrating the free piston and mechanical springs into a moving-coil type electromagnetic linear oscillating actuator (EMLOA), the structure of the proposed linear compressor is increasing compact. Moreover, the novel features, such as high thrust force constant, better controllability, and high resonant frequency, enable the linear compressor to operate most efficiently at resonance. The thrust force constant is enhanced by employing quasi-Halbach array and is tested to be high (74 N/A) and unchanged over the whole stroke. Dynamic modeling and experiment validation are performed to …analyze dynamic characteristics of the linear compressor. The experimental and simulated data agree well, by regulating the frequency and amplitude of the excitation current, the high efficiency of the EMLOA (91.7%) and the low energy volume ratio of the linear compressor (7.3 kW/(m3 /min)) indicate that the proposed linear compressor is significant energy saving compared with conventional compressors. Show more

Keywords: Direct drive, linear compressor, linear oscillating actuator, linear motor, resonance

DOI: 10.3233/JAE-150054

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 505-512, 2015

Authors: Zheng, Shijie | Tong, Liyong | Luo, Quantian

Article Type: Research Article

Abstract: The present paper derives a 3-D finite element formulation and an iterative algorithm for multiphysics analysis of coupled anomalous photovoltaic, photo-thermal and pyroelectric effects in PbLaZrTi (PLZT) ceramics. The distinction in the computation aspects of electrical potential, electrical field strength and electrical charge for 0-1 and 0-3 polarized PLZT wafers are discussed thoroughly. The element performance is improved by using an assumed natural strain approach and an enhanced assumed strain method. The transverse displacements of a bimorph 0-1 polarized PLZT actuator were predicted using the present finite element formulation and then verified with the existing analytical solution and experimental results. …The static analysis of a cantilevered beam bonded with a 0-1 or 0-3 polarized PLZT actuators was also presented and compared with the theoretical solutions. The numerical simulations demonstrate that the present formulations and algorithm possess superior performance. Show more

Keywords: Finite element, 0-3 polarized PLZT, multiphysics analysis, solid-shell element, iterative algorithm

DOI: 10.3233/JAE-150058

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 513-530, 2015

Authors: Yin, Congbo | Zhang, Zhendong | Sun, Yuedong | Xie, Nailiu | Cheng, Qiang

Article Type: Research Article

Abstract: GDI (Gasoline Direct injection) injector is one of the most important components in GDI engine, which requires high precision and dynamic response. The magnetic circuit configuration as the key part of GDI injector which decides the magnetic force, dynamic response, energy loss and temperature rising. All these factors directly or indirectly impact on the GDI injector comprehensive performance. The aim of this investigation is to optimize the magnetic circuit configuration and improve the comprehensive performance for GDI injector. The specific factors that influence the optimum operation of the GDI injector have been analyzed based on physical theories. MOSA (Multi Objective …Simulated Annealing) algorithm is used to implement the multi-objective parameters optimization for the magnetic circuit configuration. To validate the optimization results the multi-physical fields coupling simulation based on Finite Element Method (FEM) is used, and the simulation results were validated by experiments. Compared the initial configuration to the optimized one, the comprehensive performances have great improvement after optimization. The results indicate that the methods can be used to GDI injector concept design and performances prediction. Show more

Keywords: GDI injector, multi-physical fields, MOSA algorithm, FEM

DOI: 10.3233/JAE-150065

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 531-546, 2015

Authors: Yi, Shuchun | Wang, Wei | Su, Sanqing

Article Type: Research Article

Abstract: Metal magnetic memory (MMM) is an effective magnetic method in evaluating stress concentration and early damage. To get the normal component of surface spontaneous magnetic signal of the specimen under different loads, three-point flexural test and four-point flexural test of Q235B steel specimens were carried out. Von Mises yield criterion was employed to calculate equivalent stress. The results show that the magnetic signal curve has a strong regularity during loading stage. For a three-point bending specimen, the magnetic signal curve presents ``triangle'' distribution. For a four-point bending specimen, the magnetic signal curve of the flange and web present ``trapezoid'' and …``saddle'' distribution, respectively. The symmetry of magnetic signal curve can be used to determine whether a specimen is under eccentric compression. The main tendency and local extrema of equivalent stress are coinciding with that of magnetic signal. A reasonable qualitative correlation is found between the distribution of equivalent stress and magnetic signal. Show more

Keywords: Metal magnetic memory (MMM), bending test, equivalent stress, von Mises yield criterion, qualitative correlation

DOI: 10.3233/JAE-150067

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 547-556, 2015

Authors: Gan, Jinqiang | Zhang, Xianmin

Article Type: Research Article

Abstract: Hysteresis behavior of piezoelectric actuators considerably degrades the precision positioning system's performance. Many hysteresis models are developed to describe rate-independent hysteresis, while few models are presented to characterize rate-dependent hysteresis. In this paper, a modified Prandtl-Ishlinskii model is developed to describe rate-dependent hysteresis in piezoelectric actuators. The modified model integrates input frequencies and quadratic polynomials. Meanwhile, the parameters of the developed model are identified easily by the experimental data using self-adaptive particle swarm optimization (SAPSO) and the least square method (LSM) through MATLAB offline. Compared with other models, this model simplifies the modeling of complicated rate-dependent hysteresis behaviors. The validity …of this developed model is demonstrated by comparing simulation results with experimental data at different frequencies in the range of 0.5-100 Hz. Show more

Keywords: Piezoelectric actuators, rate-dependent hysteresis, Prandtl-Ishlinskii model

DOI: 10.3233/JAE-150070

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 557-565, 2015

Authors: He, Wei | Zhang, Yajie | Xu, Zheng | Cui, Xianjun | Luo, Haijun

Article Type: Research Article

Abstract: This paper presents a simple design for a nuclear magnetic resonance (NMR) sensor and its application for detecting turbine oil in two power stations. The magnet, which is composed of two identical cuboid permanent magnet blocks and two iron shimming sheets of a special shape, generates a relatively homogeneous static magnetic B0 field (∼ 364 ppm) on a 10 × 10 mm2 region of interest. In the vertical direction, it produces a constant gradient of ∼15.5 T/m within 5 mm which allows for self-diffusion measurements and 1 dimensional imaging. This NMR sensor can produce a deep penetration …depth into the samples with relatively strong and uniform B0 strength. The NMR sensor was specially designed for assessing the aging status of turbine oil in a power station, and a group of turbine oil of different service times was measured. Results demonstrate that an increase in the service time of the turbine oils clearly decreases transverse relaxation time T2 . This portable sensor can be used in fields and provide quantitative evaluation parameters of the aging status of turbine oil during periodic inspection. Show more

Keywords: Aging level, constant gradient, portable nuclear magnetic resonance (NMR) sensor, turbine oil

DOI: 10.3233/JAE-150080

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 567-576, 2015

Authors: Zhou, Zupeng | Tan, Yonghong | Dong, Ruili | Zhang, Lieping

Article Type: Research Article

Abstract: In the real application, realizing the accurate fault prediction of non-smooth sandwich system with hysteresis which widely exists in the real engineering systems is of great importance. Therefore, a novel dynamic robust observer is proposed in this paper. First, the non-smooth sandwich system with hysteresis is transformed into a system in which conventional dynamic robust observer design method can be applied by converting the non-smooth item into a general disturbance. Then, by zeros assignment and minimizing the H∞, F /H-,F indicator on the basic operation zone, the feedback matrices of this observer can be obtained. After that, …the simulation results are presented. The comparison between the proposed robust non-smooth scheme and the conventional method demonstrated that the proposed robust fault detection approach can detect the actuator and sensor faults accurately and quickly which the conventional observer can not detect the faults at all. Moreover, the missing and false alarms are effectively reduced by the robust observer. Show more

Keywords: Robust observer, hysteresis, sandwich system, fault detection

DOI: 10.3233/JAE-150081

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 577-595, 2015

Authors: He, Wei | He, Zhonghua

Article Type: Research Article

Abstract: A combination of passive shimming procedures is employed in the design of a unilateral Nuclear Magnetic Resonance magnet. The first shimming procedure used movable permanent magnets to correct the inhomogeneity of the B0 field to a relatively low level. In the second shimming procedure, the small iron pieces were used as shimming units, and their sizes and locations were predicted by using an integer programming method. Finally, the distribution of the shimming pieces was optimized and a special mathematic model was established. This hybrid technique provides a computational algorithm for optimizing the B0 homogeneity and for minimizing the number of …iron shimming pieces. A prototype unilateral NMR magnet has been built with this method. The B0 field measurement results were compared before and after the shimming. Employing this hybrid shimming method improved the uniformity of the B0 field from 4200 ppm to 796 ppm with only one iteration. Show more

Keywords: Passive shimming method, integer programming, unilateral nuclear magnetic resonance (UNMR)

DOI: 10.3233/JAE-150092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 597-606, 2015

Authors: Ezzat, M.A. | El-Bary, A.A.

Article Type: Research Article

Abstract: The model of the two-dimensional equations of magneto-thermoelasticity with fractional order heat transfer in a perfectly conducting medium is established. The method of the matrix exponential which constitutes the basis of the state-space approach of modern control theory is applied to the non-dimensional equations. Laplace and Fourier integral transforms are used. In this formulation, the governing equations are transformed into a matrix equation whose solution enables us to write the solution of any two-dimensional problem in terms of the boundary conditions. The resulting formulation is applied to a perfect conducting half-space problem. Some comparisons are shown in figures to estimate …the effects of the Alfven velocity and the fractional order on all the considered fields. Show more

Keywords: Magneto-thermoelasticity, new fractional taylor's series, state space approach, fractional calculus, numerical results

DOI: 10.3233/JAE-150095

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 607-625, 2015

Article Type: Other

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 627-633, 2015