International Journal of Applied Electromagnetics and Mechanics - Volume 53, issue 1

Authors: Wu, Li | Tao, Junwu | Lacout, Jean-Louis | Vuong, Tan-Hoa

Article Type: Research Article

Abstract: Since radiofrequency heating could be an attractive alternative over microwave heating for processing porous media, and intermittent heating was reported to be an optimization for homogeneous temperature distribution in the sample, this paper, applying both advantages, proposed a coaxial cell to research radiofrequency intermittently heating potatoes with different phases: solid, liquid and gas. In simulation, the sample and coaxial cell are both simplified into a 2D axis-symmetric model, which lowers the calculation requirement of computer but maintains the calculation accuracy. The effects of different process periods are studied and analyzed. Corresponding experiments are also conducted to measure the temperature change …during the heating process. The simulated results compare qualitatively with the measured ones. Show more

Keywords: Radio frequency heating, porous media, multiphysics, dielectric property

DOI: 10.3233/JAE-150150

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 1-15, 2017

Authors: Li, Xiangchao | Zhang, Jing

Article Type: Research Article

Abstract: In terms of the fuse breaking performance in 8/20 μ s waveform of lightning current, the method that the fuse and surge protective device can work together is proposed. When the lighting current flows through the fuse, the instant temperature of its melt stream rises, and the fuse breaking action time is first analyzed. Meanwhile, when lighting current flows through a conductor, the influence of ponderomotive force on current-carrying conductor is then analyzed. Finally, a lead aluminum alloy fuse is selected, and the impulse test is carried out using 8/20 μ s waveform of lightning current. The test conforms to …let-through energy I2 t theory when the fuse melting current under power frequency is below 5 A; while it conforms to the theory that the applied force vector sum of the transverse electric field and all directional drift electrons are ponderomotive force, when the fuse melting current under power frequency is above 5 A. Show more

Keywords: Lighting current, fuse, let-through energy, ponderomotive force

DOI: 10.3233/JAE-150154

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 17-27, 2017

Authors: Wu, Jie | Jiang, Xuezheng | Li, Qingtao | Yao, Jin | Li, Hua | Li, Zhaochun

Article Type: Research Article

Abstract: This paper presents a new configuration and optimal design of a novel multilayered cylindrical magnetorheological (MR) brake. Compared to the traditional ones, this designed MR brake employs several coils setting along the circumferential direction in order to increase the magnetic field strength within the MR fluid. Four annular working gaps of each serpentine gap are used to reduce the effect of centrifugal force at high speed rotating conditions. Furthermore, this novel MR brake provides flexible options for torque enhancement because either the axial or radial dimensions of the working gaps can be adjusted. After describing the structure, exact closed-form expressions …of the braking torque have been derived in order to calculate the braking torque and evaluate the merits of the designed MR brake. The magnetic circuit analysis of the MR brake is conducted to theoretically estimate the magnetic field strength in the working gaps. After that, simulations were performed to optimize the structure sizes of the designed MR brake, and evaluate its performance. The results indicate that the proposed MR brake can generate a considerable braking torque while maintaining a feasible magnetic circuit design and a compact structure. Show more

Keywords: Magnetorheological (MR) brake, multilayered, braking torque, magnetic circuit analysis, optimization

DOI: 10.3233/JAE-150158

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 29-50, 2017

Authors: Kouki, Hajer | Fredj, Mouldi Ben | Rehaoulia, Habib

Article Type: Research Article

Abstract: This article discusses the modeling of double star induction machines (DSIM). Its main objective is to study the impact of the stator mutual leakage inductance on the modeling of such machines, in steady-state and dynamic operations. For that purpose, experimental and simulation results are conducted on two squirrel cage induction machines with equal ratings. The stator of each machine is specifically conceived with two sets of three phase windings. Spatial shifting θ , between the two stars, is made 0° for the first machine and 30° for the second. Regarding the machine modeling, the study encompasses three cases. First, …the mutual leakage inductance is included. Second, the mutual leakage inductance is considered as a self-leakage inductance. Third, the mutual leakage inductance is simply neglected. However, by defining a couple of parameters (α _k, β _k)an original compact model is developed. The approach applies either in steady state or in transient operation. In addition, to enhance the accuracy of the modelling process, the effect of magnetic saturation is introduced in the d-q mathematical model of the double star induction machine (DSIM), whatever the electrical shifting between the two stator stars. Predictions of various electrical and mechanical characteristics have shown the importance of taking into account the mutual leakage fluxes in the DSIM modeling, especially in transient operation. Analysis of simulation and practical results has also confirmed the correct model. Show more

Keywords: Double star induction machine (DSIM), modeling, mutual leakage inductance

DOI: 10.3233/JAE-150160

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 51-61, 2017

Authors: Bao, Xiaohua | Cheng, Zhiheng | Di, Chong

Article Type: Research Article

Abstract: Air-gap eccentricity is commonly occurred in large induction motors, especially submersible motors. Based on this failure, a more accurate curved eccentricity model is established and current analysis of the faulty machine is conducted in this paper. To carry out calculation, winding function method is proposed aiming at calculation of the inductance matrix in the multi-loop model and theoretical derivation is also presented. A curved eccentricity model is set up by simulating the deflection of the shaft and such model is applied to prototype (1200 kW submersible motor). By analyzing harmonic characteristics in line current, the result proves feasibility of current …monitoring on curved eccentricity. Show more

Keywords: Curved eccentricity, winding function method, induction motor, current analysis

DOI: 10.3233/JAE-160005

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 63-76, 2017

Authors: Uygun, Durmus | Bal, Gungor

Article Type: Research Article

Abstract: The goal of this study is to address preliminary design and prototyping of a novel 5-phase segment-type switched reluctance motor (SEG-SRM) with 10/8 pole configuration. The proposed SEG-SRM includes a stator having salient poles and a rotor having segmental steel cores which are embedded in aluminum block. The operation of SEG-SRM depends on exciting two adjacent phases respectively at all times by creating mutual coupling, thus leading less eddy current effects on silicon steel sheets of the stator and better efficiency. A quick design methodology covering all geometrical details of SEG-SRM is given. This comprehensive method is useful for initial …machine design and eliminates the machines with undesired outputs. Besides, the performance characteristics of the designed SEG-SRM are investigated by finite element method (FEM). Finally, a prototype is manufactured and tested in the laboratory based on computed analytical parameters and the operational outcomes of the developed system are presented by verifying finite element studies. It is completely substantiated that this new preliminary design can be used in applications ranging from low speed to medium speed. The comparative study among simulation and experimental studies seeks to address torque production/prediction versus current variation. Show more

Keywords: Switched reluctance motor, bipolar excitation, segmental rotor

DOI: 10.3233/JAE-160006

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 77-94, 2017

Authors: Qi, Conghui | Zhao, Zhiqin

Article Type: Research Article

Abstract: An efficient computational electromagnetic method and compressive sensing (CS) algorithm are applied to investigate the multipath effects from environment for synthetic aperture radar (SAR) imaging when the target is on rough ground. This method can greatly reduce the computational time for electromagnetic (EM) simulation, so that the extra large scale problem can be solved efficiently. Besides, EM multipath effects between target and ground can be quantified. Compared to free-space problem, it is found the multipath effects will worsen the useful information and cause ambiguity in detection and identification of the targets. With the degradation of the sparsity of radar signal, …the peak signal-to-noise ratio (PSNR) will be reduced accordingly in the reconstruction of target images by using the CS algorithm. Show more

Keywords: Synthetic aperture radar, compressive sensing, multipath, computational electromagnetic

DOI: 10.3233/JAE-160009

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 95-105, 2017

Authors: Jagieƚa, Mariusz | Kulik, Marcin

Article Type: Research Article

Abstract: The paper aims to determine and analyse the frequency characteristics of an electromechanical vibration energy harvesting converter that comprises of a metal cantilever-beam spring driving a linear-motion permanent-magnet generator with a single-phase cored armature winding. The nonlinear parametric resonance phenomenon is analysed that the system exhibits due to action of the electromagnetic forces developed by the generator. In order to determine the steady-state frequency characteristics of the system a 1-D complex quasi-dynamic structural finite element model is coupled with 2-D magnetostatic finite element and circuit models. The nonlinearity and electric loading are taken into account. The region of feasible operation …is determined involving physical limitations of the system that result from the assumed system topology and physical properties of materials used. The observations on bistability of the frequency characteristics are carried out. The results show that the converter should operate loaded due to risk of spring devastation at the bistable operation point. The quasi-optimal value of loading resistance providing maximum power at average value of the external excitation force is determined. The considerations are supported by laboratory experiments. Show more

Keywords: Energy harvesters, nonlinear resonance, finite element analysis, coupled structural-magnetic-circuit analysis

DOI: 10.3233/JAE-160015

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 107-120, 2017

Authors: Liu, Baowen | Ma, Hongzhong | Ju, Ping

Article Type: Research Article

Abstract: For a good understanding of EHV GIS external induced currents in multipoint grounding systems, generation mechanism, distribution characteristics and influence factors analysis of the induced currents have been proposed in this paper. According to the structural characteristics of the multipoint grounding system, self and mutual inductances in GIS were calculated by using Biot-Savart Law. Based on Lenz's law, external flux balance equation of GIS was proposed, which can be used to calculate the induced circuiting currents. And the composition of induced currents in different locations of EHV GIS has been analyzed. Furthermore, 3-D analytical models of GIS were established. And …the finite element method (FEM) was used to analyze the influence factors and the distribution characteristics of induced currents. Not only the amplitude but also the phase angles of the induced currents were analyzed in this paper. Show more

Keywords: Multipoint grounding systems, induced current, generation mechanism, influence factor analysis, distribution characteristics

DOI: 10.3233/JAE-160017

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 121-137, 2017

Authors: Chesné, S. | Jean-Mistral, C. | Gaudiller, L. | Wang, Z.

Article Type: Research Article

Abstract: The next challenge in the field of embedded structures is the development of an efficient, energetically autonomous vibration control technique. The proposed new approach consists in transferring energy between modes of the same structure: energy is harvested in a uncontrolled mode to increase attenuation in a targeted mode. This approach may even permit a `stand-alone' design by generating constant voltages by using the structural motion with an energy harvesting technique. The proposed electrical architecture - called synchronized switch damping and harvesting (SSDH) - is composed of a harvesting circuit (synchronized switch harvesting on inductor [SSHI]), a DC-DC converter (buck-boost topology), …and a modal circuit to control vibration (similar to combining the synchronized switch damping on voltage [SSDV] and modal synchronized switch damping on inductor [SSDI] methods). The theoretical analysis and numerical simulation of this architecture addressed the transfer of modal energy through a smart structure based on an academic case: a cantilever beam. The study aimed to increase damping in a selected mode by using the energy of other modes in configurations with realistic energy distributions. The circuit and energy transfer were analyzed to determine the minimum modal contributions necessary to achieve this aim and to ensure long-term stability (steady state). Compared with traditional SSDI, the bi-harmonic excitation used with this new technique increased attenuation damping by 13 dB. The proposed general approach can be extended to the majority of complex or composite industrial structures subjected to vibration. Show more

Keywords: Semi-active control, energy harvesting, smart structures, modal energy transfer

DOI: 10.3233/JAE-160018

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 1, pp. 139-150, 2017