International Journal of Applied Electromagnetics and Mechanics - Volume 50, issue 4

Authors: da S. Fonseca, Wellington | de S. Lima, Diorge | Lima, Adry K.F. | Soeiro, Newton S. | Nunes, Marcus V.A.

Article Type: Research Article

Abstract: The main objective of this paper is to assist in the investigation of electromagnetic forces, structural deformation, stresses, and Safety factor when energizing unloaded transformers. The methodology is based on modeling of a single-phase 50 MVA transformer subjected to inrush currents through finite element method (FEM). In this perspective, the conditions of inrush currents are used to estimate the magnetic field density dispersion in the transformer and to find the values of forces in axial and radial directions. These components are distributed along the energized windings for observing the loads in high-voltage windings. Thus, this article will contributes with …the investigations of a structural Analysis on transformers when subjected to inrush current. Show more

Keywords: Electromagnetic-mechanical stress, inrush current, transformers, safety factor, finite elements method

DOI: 10.3233/JAE-150044

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 511-524, 2016

Authors: Shi, Tongyu | Wang, Dazhi | Li, Zhao | Zheng, Di

Article Type: Research Article

Abstract: In order to solve the problem of immeasurability of eddy current density on the conductor plate and magnetic field intensity in the air gap, this paper establishes the eddy current soft measurement model. Eddy current density of the PM eddy-current driver during run time can be calculated by measured data of slip speed and air gap in this model which is based on equivalent magnetic circuit. Then, the calculation formula of the torque can be deduced by applying this model. Transmit performance which provides an important basis for optimization calculation and preliminary design is also analyzed. All calculated soft measurement …results are compared with results of finite element method using ANSYS software and experimental data. FEM results and experiment results confirm the validity of the soft measurement mechanism model. Show more

Keywords: Disk-type permanent magnet eddy-current driver, equivalent magnetic circuit method, finite-element method, soft measurement

DOI: 10.3233/JAE-150096

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 525-535, 2016

Authors: Mohamed, Ramizi | Sarker, Mahidur R. | Mohamed, Azah

Article Type: Research Article

Abstract: The vibration based piezoelectric energy harvester system is considered as an alternative solution for micro-devices, especially for remote area. This paper presents an optimization approach to determine the optimal cantilever beam of a rectangular shape piezoelectric energy harvester to run the micro devices in which power is unavailable. In this study, PZT-5H material has been utilized. The motivation behind this research is to maximize the power behavior by optimizing the cantilever beam's length, width and thickness. Therefore, the proposed rectangular cantilever beam has been optimized by using modified particle swarm optimization (MPSO) algorithm and designed in COMSOL software. Finally, the …optimization results of MPSO are compared with other technique to validate the outcomes. The findings show that the performance of the proposed technique is better than other technique in terms of quality and convergence speed. Show more

Keywords: Energy harvesting, modified particle swarm optimization, materials, piezoelectric, micro-device

DOI: 10.3233/JAE-150129

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 537-548, 2016

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

Article Type: Research Article

Abstract: A new mathematical model of two-temperature electro-thermo viscoelasticity theory has been constructed in the context of a new consideration of heat conduction with memory-dependent derivative. The resulting formulation is applied to several concrete problems, a thermal shock problem and a problem for a half-space subjected to ramp-type heating as well as a problem of a layer media. The exact solutions for temperature, stress and displacement are obtained in the Laplace transform domain for each problem. According to the numerical results and its graphs, conclusion about the new theory has been constructed. The predictions of the theory are discussed and compared …with dynamic classical coupled theory. The result provides a motivation to investigate conducting thermoelectric viscoelastic materials as a new class of applicable materials. Show more

Keywords: Thermoelectric viscoelastic materials, two-temperature theory, memory-dependent-derivative

DOI: 10.3233/JAE-150131

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 549-567, 2016

Authors: Xue, Xiaoyan | Tian, Xu | Zhang, Di | Liu, Xudong

Article Type: Research Article

Abstract: Positioning stage with high resolution and high stiffness are always required in the micro/nano manipulation. This paper presents the design, fabrication and experimental tests of a piezo-driven positioning stage based on the inchworm principle, which can provide a large motion range with high resolution and high stiffness. The positioning stage mainly consists of a monolithic compliant mechanism and four piezoelectric actuators, which form one linear driving unit and two clamping units with complementary structures. Two piezoelectric actuators connected in parallel are utilized to drive the linear moving section for high stiffness. To facilitate the parameter design, the analytical models are …derived in detail and validated by finite element analysis. A prototype of the positioning stage is designed, fabricated and tested to further demonstrate the feasibility of the proposed idea. Experimental results well verify the effectiveness of the developed design. Show more

Keywords: Precision positioning, piezoelectric actuator, compliant mechanism

DOI: 10.3233/JAE-150134

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 569-581, 2016

Authors: Parent, Guillaume | Penin, Rémi | Lecointe, Jean-Philippe | Brudny, Jean-Fran\c cois | Belgrand, Thierry

Article Type: Research Article

Abstract: The most critical areas in power transformers are their corner joints where the magnetic flux distribution presents a very high heterogeneity. This heterogeneity results from several parameters such as the geometry of the magnetic core, the anisotropy level of the electrical steel laminations and a critical induction. This paper is focused on the magnetic steel grades influence on the critical induction, adding a new parameter to those classically considered, such as the number of steps in a multiple step lap stack. Due to the difficulty to perform local measurements inside a real transformer corner, the study is performed both experimentally …and by Finite Element analyses on a simplified magnetic core structure. The paper highlights that, in a corner of a core, it exists a critical induction level which depends on the magnetic steel grades and that, in a lamination, the magnetic flux density value along the Transverse Direction can be of the same order that it has along the Rolling Direction. Show more

Keywords: Finite element method, grain oriented electrical steel, magnetic cores, transformers

DOI: 10.3233/JAE-150135

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 583-592, 2016

Authors: Liu, Zhe | Su, Ying | Li, Yaping | Pan, Zhen | Wang, Xiuchen

Article Type: Research Article

Abstract: Numerical calculation of shielding effectiveness (SE) of electromagnetic shielding fabric (EMSF) is a research difficulty and there is not an effective method to resolve the difficulty at present. The finite difference time domain (FDTD) method is used to study this issue in this paper. Firstly, this paper constructs a structure model based on the warp and weft densities and yarn diameter according to the structure feature of the EMSF. Secondly, a physical model of the EMSF is built by determining the partition coefficient, the Yee's mesh discretization method, and the absorption boundary which are suitable for the structure model. Then …the excitation parameters are set using the EastFDTD electromagnetic computing software and the SE is obtained by the numerical calculation for the physical model. Finally, a number of silver fiber EMSFs and stainless steel fiber EMSFs with different fabric weaves, densities and metal contents are tested to verify the proposed model. The calculation data are compared with actual test data. By analyzing the differences and influencing factors between the two data, we concluded that the proposed model can calculate the SE of the EMSF and the results were satisfied. This paper provides a new method for the numerical calculation of the SE of the EMSF, and possesses an important reference value for the SE forecast, shielding mechanism analysis, shielding rules researches and related shielding electromagnetic computation of the EMSF. Show more

Keywords: Finite difference time domain, electromagnetic shielding fabric, shielding effectiveness, numerical calculation

DOI: 10.3233/JAE-150144

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 593-603, 2016

Authors: Li, Ran | Li, Lin

Article Type: Research Article

Abstract: To study the characteristics of wireless power transfer (WPT) resonators via magnetic resonant coupling (MRC), distributed parameter models based on partial element equivalent circuit (PEEC) are built for MRC-WPT resonators and coupling link between two resonators, which is essential to design a MRC-WPT system. The track of one turn in WPT coil is modeled as a complete ring carrying constant current, and the parasitic parameters and high-frequency losses are considered in this modeling method. The circuit parameters of PEEC network are calculated by numerical integrals and analytical formulas. This modeling method can predict resonant frequency and power transfer capability for …MRC-WPT system. Impedance and scattering parameter S21 of circular spiral resonators are also calculated by method of moments (MoM), and the proposed modeling method shows good agreement with the simulated results and has high calculation efficiency. Two types of WPT resonators are designed in laboratory. Impedance and scattering parameter S21 are measured for each of the cases, and the results show that the PEEC modeling method has a better accuracy and can predict resonant frequency and power transfer capacity for MRC-WPT system. Show more

Keywords: Magnetic resonant coupling (MRC), partial element equivalent circuit (PEEC), scattering parameter, wireless power transfer (WPT)

DOI: 10.3233/JAE-150145

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 605-615, 2016

Authors: Zhang, Yang | Lin, Heyun | Fang, Shuhua | Huang, Yunkai

Article Type: Research Article

Abstract: Permanent magnet vernier machine (PMVM) based on flux modulation principle has attracted increasing attention in low-speed direct-drive applications due to its high torque capability. A dual-stator PMVM topology with sandwiched spoke-array PM rotor is presented to produce higher air-gap flux density and larger torque in this paper, and the space utilization and the energy conversion efficiency are improved significantly. Two representative dual-stator PMVMs (DS-PMVMs) are designed with this topology, the pole/slot combinations and gear ratios of which are 18 slots/30 poles and 18 slots/28 poles, 5 and 3.5, respectively. In order to reveal the advantages of the proposed topology and …assess the torque characteristics of the proposed machines with different pole/slot combinations, the electromagnetic characteristics of these two machines are quantitatively compared and analyzed by using finite element method (FEM). The results demonstrate that the 18 slots/28 poles DS-PMVM can offer higher output torque, lower torque ripples, lower cogging torque and higher power factor owing to its optimal pole/slot combination. In addition, the unbalanced magnetic pulls (UMPs) of the two machines are also investigated, and the UMP of the 18 slots/30 poles DS-PMVM is smaller than that of its counterpart due to its symmetrical winding. Show more

Keywords: Direct-drive, dual stator, flux modulation, permanent magnet machine, vernier machine

DOI: 10.3233/JAE-150148

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 617-626, 2016

Authors: Su, Yu-Gang | Zhang, Shuai | Hu, Chao | Tang, Chun-Sen | Zhou, Wei

Article Type: Research Article

Abstract: Transmitter coil is one of the most critical part in an inductive power transfer (IPT) system for electric vehicles (EVs) application. For the traditional transmitter coils, due to the switch process between the adjacent coils, two serious problems of pick up voltage fluctuation and high power loss on the windings affect the stability and efficiency of the wireless EV charging. In order to solve these problems, this paper proposes a novel segmented transmitter coil for wireless power transfer on EV. A mutual inductance model is established based on the Neumann's Formula, moreover, a key parameters selection method and turns ratio …optimization method of the proposed segmented transmitter coils are also presented to keep the mutual inductance in a constant level while the transmitter coils switching one by one. Both of the simulations and experimental results verify the validity and effectiveness of the proposed transmitter coils and its key parameters selection method. Show more

Keywords: Magnetic coupler, transmitter coils switching, inductive power transfer (IPT), electric vehicle (EV)

DOI: 10.3233/JAE-150149

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 627-636, 2016

Authors: Park, Eui-Jong | Suzuki, Kenji | Kim, Yong-Jae

Article Type: Research Article

Abstract: Along with the increased interest in high-load transport system, the linear motor has evolved from the conventional single-sided model to a double-sided model with armatures on both sides of the mover. However, the linear motor generally has armatures installed on the full length of the transport path, resulting in the increase in material costs and manufacturing time and thus limiting the application of this double-sided linear motor to long-distance transport systems. As a means to solve this problem, in this study, we propose a stationary discontinuous armature system and solve its problem which increasing the cogging force by ends between …armatures. Show more

Keywords: Double-sided PMLSM, discontinuous armature, armature offset, end cogging force, ripple, winding method

DOI: 10.3233/JAE-150152

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 637-645, 2016

Authors: Sun, Tongsheng

Article Type: Research Article

Abstract: This study aims to improve the directivity of coupled antennas for microwave heating of asphalt mixture. For this purpose, the total electric fields radiated by two antennas were modeled on H & E-planes, the antenna radiation power densities on H & E-planes were explored, and the directivity factor models of coupled antennas on H & E-planes were established. Analysis of the relationship between the directivity factor on H & E-planes, the gap between adjacent horn antennas, the structure parameters of horn antennas reveals that the directivity factor is increased with an increase in the horn length inside H & E-planes, …begins to increase and then shows a downward trend after reaching the peak with an increase in aperture length, and is reduced with an enlargement of the antenna gap. Based on the findings, recommended values for the configuration parameters of the microwave heating antenna, including optimum length, optimum aperture size, and optimum gap size of the antenna array, were suggested to increase electromagnetic field distribution uniformity. Show more

Keywords: Asphalt mixture, microwave heating, directivity factor, horn antennas

DOI: 10.3233/JAE-150153

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 647-663, 2016

Article Type: Other

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 665-671, 2016