International Journal of Applied Electromagnetics and Mechanics - Volume 53, issue 4

Authors: Gong, Fei | Li, Xin | Weng, Chun-Sheng

Article Type: Research Article

Abstract: In this paper two-dimensional (2D) numerical simulations have been carried out taking into account the effects of different layered armatures on melt-wave erosion (MWE) in electromagnetic launcher. A 2D model is developed and the finite difference method is utilized to solve the unsteady magnetic diffusion and heat transfer equations simultaneously. The results indicate that erosion occurs at the rear corner of the armature and spread along the armature/rail (A/R) interface. Three different layered armatures are used to prevent MWE and delay the onset of the transition. The inverse L-shaped layered pattern shows the best performance. Important electrothermal and geometrical parameters …of the contact layer are analyzed through comparing the erosion time, erosion distance and maximum temperature. It is observed that a protective layer with high electrical conductivity and thermal conductivity is useful to restrain the spread of MWE. The results are inspiring and contribute to the armature design. Show more

Keywords: Electromagnetic launcher, layered armature, melt-wave erosion, finite difference method

DOI: 10.3233/JAE-150139

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 579-589, 2017

Authors: Zhou, Yu | Li, Huaishu | Xue, Zhiqiang | Xia, Fei | Man, Xin

Article Type: Research Article

Abstract: In this paper, an analytical method for predicting the armature-reaction field distribution of surface-mounted permanent-magnet machine accounting for slots in the stator and rotor was presented. The analytical model is divided into three types of subdomains. And the field solution of each subdomain is obtained by applying the interface and boundary conditions. The non-overlapping or overlapping windings are also considered. The prototype machine with 4-poles/24-stator slots/20-rotor slots is used for validation. The FE (finite element) results confirm the validity of the analytical results with the proposed model.

Keywords: Permanent-magnet machines, armature reaction field, slot, subdomain model

DOI: 10.3233/JAE-150176

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 591-604, 2017

Authors: Fang, Lei | Tan, Guojun | Yin, Shi | Hu, Kun

Article Type: Research Article

Abstract: This paper focuses on the analysis of the starting capacity and temperature field of the line-start permanent magnet synchronous motor with the anti-salient pole. In order to further improve the performance of the traditional LSPMSM, the magnet structure is optimized to get better starting properties. Further, the models have been applied to investigate the impact of anti-salient pole on the efficiency and power factor. The temperature field of proposed motor with anti-salient pole has been compared to the traditional LSPMSM with classical rotor. Prototype machines with the two rotors have been built and tested. Experimental results are compared in terms …of starting, efficiency, power factor and temperature. It has been found that anti-salient pole improves the overall properties of the LSPMSM. Show more

Keywords: Line-start permanent magnet synchronous motor, anti-salient pole, starting characteristic, temperature field

DOI: 10.3233/JAE-150179

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 605-616, 2017

Authors: Napieralska-Juszczak, Ewa | Komeza, Krzysztof | Morganti, Fabrice | Sykulski, Jan K. | Vega, Guillaume | Zeroukhi, Youcef

Article Type: Research Article

Abstract: During manufacturing of multi-strand cables the conductors are subjected to twisting and pressing which result in a creation of contact regions between individual wires. The resistivity of such contact regions differs from the resistivity of copper or aluminum. In this paper the resistivity is established by comparing measurements of resistivity with simulations using a finite element method. The non-homogeneity of the contact imprint has been accounted for and the presented results show the dependence of the contact resistance on several parameters, including compression force, imprint depth, intersecting angle and stranding pitch.

Keywords: Contact resistance, contact area, compressing force, mechanical deformation, multi-strand cables

DOI: 10.3233/JAE-160025

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 617-629, 2017

Authors: Hussain, N. | Karsiti, M.N. | Yahya, N. | Jeoti, V. | Yahya, N.

Article Type: Research Article

Abstract: Wavelet-based numerical method for solution of partial differential equations (PDE) is more efficient and accurate than the conventional finite difference (FD) and finite element (FE) techniques. The application of wavelet for solving the governing field equations of marine controlled source electromagnetic (CSEM) method is considered to be relatively new. Among the important properties of wavelet includes locality in space, compact support, adaptivity and orthogonality. These properties allow the wavelet-based numerical solution to provide an accurate, efficient and powerful numerical solution to PDE. In this work, a wavelet Galerkin (WG) method is proposed for the computation of EM field in two …dimensional stratified layered media that is radiated by a mobile point source. The proposed method solves the wave equation of marine CSEM by using compactly supported Daubechies wavelets which are differentiable according to the requirement. The results generated are verified against with solution obtained by FD and FE methods. The distinctive features of the proposed method shows that the obtained results are close enough and it effectively approximate the solution with very less computational time as well as elapsed memory. Show more

Keywords: Wavelet, electromagnetic, Daubechies, geophysical modeling, forward modeling

DOI: 10.3233/JAE-160028

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 631-644, 2017

Authors: Ding, Xiaofeng | Liu, Guanliang | Zuo, Zongyu | Guo, Hong

Article Type: Research Article

Abstract: This paper presents an optimal design of an axial flux mircoelectromechanical systems (AF-MEMS) micromotor with enhanced power density and efficiency. The micromotor is characterized with dual-rotor and external diameter only around 10 mm. The characteristics of the MEMS micromotor are presented and modeled for optimization design. With the simple but powerful population-based stochastic search technique for solving global optimization problems, the differential evolution (DE) algorithm is adopted for the optimization design of this special motor. Furthermore, according to the characteristics of the micromotor, such as nonlinear, small size and different convergences of optimal variables, a constraint matrix (CM) and a …depth search (DS) are proposed to enhance the conventional DE. Such improved DE is beneficial for the search efficiency and accuracy according to calculation results whilst giving an optimal motor with high power density and high efficiency. Experiments and 3D finite element analysis (FEA) are employed to analyze the optimized micromotor and verify the feasibility of the proposed DE. Show more

Keywords: An axial flux microelectromechanical systems (AF-MEMS), differential evolution (DE), power density, efficiency, finite element analysis (FEA)

DOI: 10.3233/JAE-160035

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 645-661, 2017

Authors: Zhu, X.J. | Ma, Y.H.

Article Type: Research Article

Abstract: In this paper, a radial electromagnetic gear with less pole difference is proposed. Operating principle of the radial electromagnetic gear is introduced and equations of the geometrics for the radial electromagnetic gear are deduced. The equations of the magnetic induction intensity for the stator windings are given and the electromagnetic field distributions of the stator windings are investigated. The equations of the torques between the planetary rotor and stator windings are developed. The available parameters of the radial electromagnetic gear with less pole difference are presented. Changes of the maximum torque between the planetary rotor and stator windings along with …the available parameters are researched. The result shows that the pole-pair number, the radial tooth thickness, and the center distance of the gear have obvious influence on the maximum torque. In order to obtain large load carrying ability of the radial electromagnetic gear, the maximum torque must be improved. So a large radial tooth thickness, a proper pole-pair number, a small center distance, a large winding's circle number, and large current should be chosen. Show more

Keywords: Eelectromagnetic gear, less pole difference, torque, magnetic induction intensity, parameters

DOI: 10.3233/JAE-160042

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 663-672, 2017

Authors: Su, Yu-Gang | Ma, Jun-Hao | Xie, Shi-Yun | Zhao, Yu-Ming | Dai, Xin

Article Type: Research Article

Abstract: The capacitive power transfer (CPT) technology is a novel solution to transfer power wirelessly by using electric field. Although there is an insulating layer on the coupling plates, leakage electric field is still existing around the plates. So there might have an electric shock hazard when a human body touches the conductors placed around the coupling plates. To solve this problem, an equivalent capacitor model of the metallic conductor and the coupling plate is established. Besides, a human body impedance model is introduced to obtain equivalent circuits of the CPT system when a human touches the conductor. The formulas of …the four coupling plate voltages are derived for a full bridge series resonant CPT system. Moreover, the distributed voltages of the conductor placed above different coupling plates are given. The correctness of the theoretical analysis has been verified by the experimental results. Show more

Keywords: Capacitive power transfer (CPT), coupling plate, distributed voltage, safety issues

DOI: 10.3233/JAE-160046

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 673-684, 2017

Authors: Yan, Liang | Zhang, Lu | Wang, Tianyu | Jiao, Zongxia

Article Type: Research Article

Abstract: Conventional linear machine consists of only one stator and one mover. In this paper, a slotless permanent magnet (PM) linear motor with multiple tubular movers is proposed to improve the efficiency of stator field. The outer and inner movers can produce independent motions by interacting with the PM stator. It can be used in large systems requiring multiple driven elements to increase space utilization. The employment of tubular structure helps to reduce the flux leakage and improve the system working efficiency. The design concept and operating principle of the proposed linear machine are introduced. The magnetic field distribution is formulated …by using Laplace's and Poisson's equations of magnetic vector potential. Numerical computation is also conducted on the flux field. It shows that the derived analytical result fits with finite element analysis (FEA) well. The influence of winding currents on the magnetic field distribution is also considered. The magnetic field distribution in four different working situations is simulated, i.e., nonexistence of working current, power supply for inner mover and outer mover respectively, and energizing both movers simultaneously. It is verified that the winding current does not affect the magnetic field distribution significantly and the multiple movers can achieve linear motions independently. Show more

Keywords: Actuator, magnetic field, tubular machine, permanent magnet

DOI: 10.3233/JAE-160055

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 685-695, 2017

Authors: Xu, Wei | Ding, Wenfeng | Zhu, Yejun | Yang, Changyong

Article Type: Research Article

Abstract: This article mainly carries out the numerical simulation and experimental verification of heating temperature characteristics during fabrication of monolayer brazed cubic boron nitride (CBN) grinding wheels using the rotating induction brazing technique. Effects of the critical heating factors in the rotating induction brazing process, such as induction current, current frequency, heating gap and scanning speed are analyzed, respectively. It was found that, the maximum value of heating temperature increases nonlinearly with the increasing induction current and current frequency, and with decreasing of the heating gap and scanning speed. The empirical formula of heating temperature is established, and the rotating induction …heating parameters are accordingly optimized to control the brazing temperature range of 880-940°C, which has been confirmed valid during the rotating induction brazing operation of monolayer CBN grinding wheels. Show more

Keywords: Rotating induction brazing, numerical simulation;, heating temperature;, optimization;, steel wheel matrix

DOI: 10.3233/JAE-160083

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 697-713, 2017

Authors: Hasan, Alfaisal A.

Article Type: Research Article

Abstract: The electrodynamic stability of a dielectric selfgravitating streaming fluid cylinder, density ρ^e, ambient with a different dielectric selfgravitating streaming fluid, density ρ^i, has been discussed. The problem is formulated, the governed basic equations are solved and upon appropriate boundary conditions the dispersion relation is derived and discussed analytically and the results are verified numerically. The electrodynamic force has very effective effect on the dielectric streaming system and this is physically explained. The streaming has a strong destabilizing influence for all short and long wave lengths. The stable and unstable states are depending on ρ(=ρ^e/ρ^i) an ρ < 0.5 there …will be stable and unstable domains but when ρ > 0.5 the system is totally unstable with infinite maximum growth rate. The gravitational instability of the present model will be suppressed. Show more

Keywords: Electrodynamic, selfgravitating, streaming

DOI: 10.3233/JAE-160084

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 715-725, 2017

Authors: Li, Junfeng | Yin, Haibin | Tan, Yuegang

Article Type: Research Article

Abstract: The purpose of this research is to present a new kind of soft finger which can achieve variable stiffness actuation by heating the fixed SMA fibers. First, the material and design method of the soft finger are described. Next, the stiffness of the finger with different heating currents for the SMA is measured and the results show the increase of stiffness around 21.5 per cent from the low stiffness to high stiffness. Finally, the maximum pulling force of the soft gripper with variable stiffness is measured, which demonstrates that output force of the finger's tip can be adjusted by changed …stiffness. This variable stiffness structure for a manipulator could greatly benefit applications such as human-safe robotics and systems in which robots need to exhibit high flexibility to conform to their environments. Show more

Keywords: Variable stiffness, SMA actuator, gripper

DOI: 10.3233/JAE-160091

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 727-733, 2017

Authors: Wang, Xiaoguang | Zhang, Xiao | Zhao, Xuan

Article Type: Research Article

Abstract: Magnetic bearing with redundant structure can regain supporting ability by way of reconstruction under the condition of coil failure. In this paper, the influence of parameters on stiffness is studied by way of simulation and experiment using PID control algorithm, and the reconstruction strategy is proposed. The range of feasible parameters of redundant reconstruction is determined and the weight of the parameters is found out. The control parameter that makes stiffness of magnetic bearing constant is found out. The experimental results are in agreement with the simulation results in tendency, but the experimental results are less than the simulation results.

Keywords: Magnetic bearing, coil failure, reconstruction stiffness, PID control algorithm

DOI: 10.3233/JAE-160095

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 735-743, 2017

Authors: Lu, Qinfen | Ma, Xuedong | Huang, Xiaoyan | Ye, Yunyue

Article Type: Research Article

Abstract: Linear switched-flux permanent-magnet machines (LSFPMMs) exhibit high thrust force density and low cost, which is especially suitable for long stroke application. They have big normal force so that the assembly becomes difficult. The mechanical flux adjuster is a suitable method to lower the big normal force. This paper investigates the performances of two kind odd primary pole LSFPMMs with mechanical flux adjuster based on FEA, including E- and C-core structure. The analysis results show this method can effectively lower the magnetic field in air gap. The structure parameters of mechanical flux adjuster are also optimized, and the operating curves are …calculated with or without mechanical flux adjuster. With this method, not only does the assembly become easier, but also the operating range extends at small load. Show more

Keywords: Linear machines, longitudinal end effect, mechanical flux adjuster, odd primary pole, switched-flux

DOI: 10.3233/JAE-160104

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 745-756, 2017

Authors: Huang, Yunkai | Guo, Baocheng | Guo, Youguang | Zhu, Jianguo | Hemeida, Ahmed | Sergeant, Peter

Article Type: Research Article

Abstract: In this paper, an analytical quasi three-dimensional method is used to model an axial flux permanent magnet (AFPM) machine with various eccentricities. AFPM machines (AFPMMs) have various advantages but they are sensitive to geometrical imperfections for manufacturing aspect. The main aim of this paper is to propose a general analytical model to analyze the AFPMMs with various types of eccentricities. The radial and tangential magnetic flux densities in the air gap under healthy condition are obtained via combination of Maxwell's equations and Schwarz-Christoffel (SC) mapping firstly. Next, in order to investigate the eccentricities, equations for air gap length and radii …are deduced. The back electromotive force (EMF) is calculated and compared with those from healthy condition and finite element (FE) analysis, respectively. The results show that the analytical predictions agree well with the FE results. Moreover, using this method has a significantly less time consuming than the 3D FM simulation process, which is a great advantage of this method. Finally, the analytical model is verified via experimental results. Show more

Keywords: Analytical model, axial flux PM machines, back EMF, conformal mapping, double rotor, eccentricities

DOI: 10.3233/JAE-160106

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 757-777, 2017

Article Type: Other

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 779-788, 2017