International Journal of Applied Electromagnetics and Mechanics - Volume 55, issue 1

Authors: Tan, Cao | Chang, Siqin | Liu, Liang

Article Type: Research Article

Abstract: Moving-iron electromagnetic actuators have been widely used in industry. But the properties are conflict in high levels of linear force, long stroke, low power consumption and high force/volume ratio. A hybrid excited linear actuator (HELA) was proposed to provide an innovative high-performance solution for direct drive valves. The characteristics of static electromagnetic force were optimized and analyzed. Meanwhile, dynamic performance was simulated by 3D finite element method taking into account the eddy current loss of materials. The simulation results agree well with the experiments. And the results show that the prototype’s magnetic paths distribution is regulated by the structural parameters, …which leads a linear output force within a stroke of ± 3 mm. Besides, the prototype’s force/volume ratio is up to 4.5 × 10 7 N/m 3 . The holding force at the ends of stroke is more than 120 N. Therefore the holding current is eliminated, which reduces the power consumption effectively. Furthermore, the prototype’s time of step voltage response is 4.3 ms and frequency response (- 3 dB) of the displacement reaches about 60 Hz. Additionally, the eddy current is a significant factor affecting the dynamic performance, which increases more than 8 percent in the step voltage response time. Show more

Keywords: Electromagnetic linear actuator, hybrid excitation, direct drive valve, force behavior, dynamic performance

DOI: 10.3233/JAE-160072

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 1-12, 2017

Authors: Dahlmann, Martin | Sattel, Thomas

Article Type: Research Article

Abstract: A partial inverse design is introduced to derive a mutually coupled two-phase reluctance machine concept. The inverse design part begins with the torque as a function of inductance and current. For given torque characteristics the required inductance characteristics are calculated and including a magnetic circuit yields required reluctance or permeance characteristics for the air gaps. Such inverse design focuses on possibilities of reluctance machines in general, independent of any machine geometry. The derived two-phase motor concept uses self and mutual inductance independently to obtain up to four shifted harmonic torque characteristics. This allows to generate a bidirectional torque at every …rotor position. Thus, there is no self-start problem and reduced torque ripple. The theoretical operation is shown with a linear magnetic circuit model and non-linear FEM calculations for a 2D and a 3D machine design. Show more

Keywords: Reluctance, machine, design, inductance, characteristic

DOI: 10.3233/JAE-160087

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 13-27, 2017

Authors: Deng, Xianming | Cheng, En | Liu, Na | Li, Shaowu | Wang, Wenwen

Article Type: Research Article

Abstract: Considering the challenge that the parameter of inductor is fixed and its adjustment is difficult in traditional power electronic circuit, herein we present a newly structural transformer with adjustable leakage inductance which integrates transformer and inductor. Its leakage inductance can be adjusted online. Secondary winding of the newly structure transformer is connected in series with the inductance winding and the leakage inductance can be changed by adjusting the contact area of the transformer core and the inductor core. The structure and principle of the transformer with adjustable leakage inductance are introduced. A newly structure transformer is designed using equivalent magnetic …circuit method. The transformer with leakage inductance adjustable are modeled and simulated by finite element simulation software Ansoft Maxwell. The variation of inductor inductance with the core contact area and the electromagnetic properties of the new transformer with leakage inductance adjustable are shown in this thesis. Finally, the transformer with leakage inductance adjustable is manufactured, and the experimental platform is built. The results show that the principle of the transformer with leakage inductance adjustable is reasonable and its design is feasible. Show more

Keywords: Leakage inductance adjustable, transformer, finite element analysis

DOI: 10.3233/JAE-160110

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 29-43, 2017

Authors: Zhao, Jianhui | Shi, Yong | Grekhov, Leonid | Ma, Xiuzhen

Article Type: Research Article

Abstract: Numerical calculations of high speed solenoid valves (HSV) are performed to understand the effects of the driving current and structural parameters on electromagnetic energy conversion in HSV. The results show that the driving current plays a prominent role on the capability of electromagnetic energy conversion. The changes in the electromagnetic force are determined by the total magnetic reluctance and the range of the driving current. For large driving currents, the capability of electromagnetic energy conversion is not significantly influenced by the driving current and is only slightly affected by the working air-gap. The larger the driving current becomes, the smaller …the increase of the electromagnetic force is with an increasing of the working air-gap. Within a certain range of driving currents, the armature thickness has positive effects on the capability of electromagnetic energy conversion, but the effects are not significant at large driving currents. At different driving currents, the effect of the number of coil turns on the electromagnetic force is mostly determined by the effects of the coil turns on the total magnetic flux and the total magnetic reluctance. Show more

Keywords: Static electromagnetic characteristic, solenoid valve, common rail injection, driving current, working air-gap

DOI: 10.3233/JAE-160129

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 45-60, 2017

Authors: Wang, Junhua | Dai, Zhongyu | Long, Mengjiao

Article Type: Research Article

Abstract: In this paper, a wireless charger based on the novel witricity technology has been proposed for implanted deep brain stimulation (DBS). The simulation structure and the experiment model have been illustrated respectively. And the inductance, the resistance, the coupling coefficient have been compared between the simulation results and the measured results. Finally, the charger for implanted DBS power supply was proposed. The simulations have been done for coils with different copper tape arrangements to select the well match. Then a fabricated small “box” for the receiver has been designed and a head phantom has been constructed for the study of …electrical energy delivery. The experiments have been carried out and the input voltage, input current, charging voltage and charging current have been measured for verification. In the end, the electric distributions have been studied to make sure its safety for human beings. Show more

Keywords: Wireless charger, witricity technology, deep brain stimulation, copper tape arrangements, transmitter, receiver

DOI: 10.3233/JAE-160135

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 61-74, 2017

Authors: Díaz Flórez, Guillermo A. | Mombello, Enrique E. | Voss, Stephan

Article Type: Research Article

Abstract: This paper presents a new methodology to calculate eddy current losses and Lorentz forces in foil winding transformers. This methodology is based on the equivalent winding current distribution in the foil winding and the iron core obtained by means of the Semianalytic Integral Method (SAIM) [1 ]. The main advantage of the calculation technique presented in this paper is that it is based on mathematical expressions which are compact and easy to evaluate, thus achieving a considerable reduction in the overall time required to determine the design parameters of the transformer. The results obtained from the proposed formulation have been …compared to those obtained using the finite element method (FEM) using as a case study a 10 MVA transformer and an excellent agreement between both techniques has been obtained. Show more

Keywords: Integral methods, surface current, finite-element method (FEM), skin effect, proximity effect

DOI: 10.3233/JAE-160144

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 75-88, 2017

Authors: Song, Ningran | Ma, Shuyuan | Zhang, Zonqing

Article Type: Research Article

Abstract: A novel sandwiched maglev positioning stage is proposed in this paper. Mathematical model and finite element models are made up to analyze levitation force and driving force on maglev stage in two different structures—ordinary and sandwiched, which can verify the better performance of sandwiched structure. Also, the analysis of the relation between current input and working forces help a lot to the control of the maglev stage.

Keywords: Sandwiched, maglev, finite element analysis

DOI: 10.3233/JAE-160152

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 89-100, 2017

Authors: Yang, Maosheng | Ding, Changjiang | Zhu, Jingcheng

Article Type: Research Article

Abstract: The aim of this work is to study the drying quality of Chinese wolfberry fruits and the effect of energy consumption on the drying process using electrohydrodynamic (EHD) drying. The drying rate, nutrient content and energy consumption of the Chinese wolfberry fruits which were dried in an EHD system at two levels of electric field intensity and five levels of the discharge gap were investigated and compared against oven drying and the control. The results showed that the drying rate have no significant difference at different voltages and discharge gaps under same electric field intensity. Experimentally, the polysaccharides content in …the EHD system was improved when compared to oven drying. The specific energy consumption decreased with the decrease of the discharge gap and voltage. The drying rate can be enhanced and the energy consumption was greatly reduced at lower discharge gap and voltage in EHD system. The effect of degree of cell damage is smaller during EHD drying. Therefore, this work provides guidance for optimizing and improving the drying efficiency of Chinese wolfberry fruits in an EHD system. Show more

Keywords: Electrohydrodynamic drying, nutrient content, energy consumption, Chinese wolfberry

DOI: 10.3233/JAE-170010

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 101-112, 2017

Authors: Su, Yufeng | Zhang, Kun | Ye, Zhitong

Article Type: Research Article

Abstract: To better understand and make use of its characteristics, a diamagnetic levitation structure, which consists of NdFeB permanent magnets and pyrolytic graphite sheets, is studied in this report. Finite element analysis is performed to analyze the influence of floating magnets with different structures and sizes on the equilibrium spacing and movement space of a floating magnet. The key factors that affect the equilibrium spacing and movement space are obtained, and the effectiveness of the simulation is verified experimentally. Compared to the experimental results, the maximum simulation error is less than 10%. A forced vibration model with a single degree …of freedom is used to denote the diamagnetic levitation structure, and the natural frequency is analyzed to be 4.87 Hz for the structure in this study. The nonlinear characteristics of the system are studied to obtain a better understanding of the vibration of the nonlinear system. The diamagnetic levitation structure has great potential in the application of vibration energy harvesters or noncontact sensors and actuators. Show more

Keywords: Diamagnetic levitation, magnet, pyrolytic graphite, nonlinear, movement space, equilibrium position

DOI: 10.3233/JAE-170011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 113-128, 2017

Authors: Tian, Lisi | Yu, Qiang | Tang, Chaoquan

Article Type: Research Article

Abstract: In this paper, a novel analytical magnetic circuit network model is proposed to simulate saliency effect with high magnetic saturation for electrical machines. Such a network is featured by dividing magnetic paths according to airgap flux distribution characteristics. Magnetic saturation on salient poles is modeled with discretized and in size adaptable reluctance elements. The method uses basic magnetic circuit principles without empirical estimation. The method can be applied without power or speed limit to various machine geometries featured by prominent saliency structure.

Keywords: Switched reluctance machine, double saliency structure, magnetic equivalent circuit, magnetic saturation, flux linkage

DOI: 10.3233/JAE-170018

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 129-138, 2017

Authors: Liao, Y.-H. | Zhu, H.-C. | Huang, K.-M.

Article Type: Research Article

Abstract: In this paper, an efficient finite element method (FEM) in solving electromagnetic scattering from body coated by thin-layer materials based on nonlinear coordinate transformation is presented. To solve scattering thin-layer material problems accurately, the traditional FEM employs rigor meshes to discretize the thin-layer structure resulting in numerous meshes, unknowns and ill-conditioned matrices. It requires much expensive storage and computational time. The proposed approach employing nonlinear coordinate transformation maps the dense thin-layer geometry space into a sparse space. In this manner, the need of rigor local mesh refinement can be eliminated. Thus, it provides an efficient approach to compute scattering from …body coated by thin-layer materials. Two examples validate the efficiency and accuracy of the proposed method. Show more

Keywords: Thin-layer materials, efficient FEM, electromagnetic scattering, nonlinear coordinate transformation, constitution relationship

DOI: 10.3233/JAE-170028

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 139-150, 2017

Authors: Santos, Kenedy Marconi G. | Novo, Marcela Silva | Fontgalland, Glauco | Perotoni, Marcelo Bender

Article Type: Research Article

Abstract: This paper presents a simple methodology to measure the shielding quality in coaxial cables and connectors through the Shielding Effectiveness (SE) parameter at high frequencies. The discovery of complications as soon as possible is of paramount importance in order to avoid unpredicted costs in advanced phases of the project. This proposal describes an SE measurement setup using standard Electromagnetic Compatibility instrumentation such as electric field probe, signal generator, and power meter in a semi-anechoic shielded chamber and comparing physical measurement with computational simulations. A virtual model has been created based upon the physical coaxial cable, respecting dimensions and materials characteristics. …The agreement between measurements and simulations is good in the considered frequency range 240 MHz to 3 GHz. Show more

Keywords: Electric field, shielding effectiveness, coaxial cable, connectors

DOI: 10.3233/JAE-170032

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 151-166, 2017

Authors: Jiang, Zhaoneng | Zhang, Qingchun | Zha, Liping | Yang, Xiaoyu

Article Type: Research Article

Abstract: For the electrically large problems, the discrete unknowns of surface integral equation are very large, resulting in the matrix condition is relatively poor. The high order hierarchical basis functions are utilized to reduce the discrete unknowns, thereby reducing the memory consumption and computation time. Meanwhile, modified multilevel compressed block decomposition (MMLCBD) is applied to accelerate the matrix-vector multiplication operations, which utilizes novel technique to improve the solving efficiency by combining a less accurate truncating threshold in MLCBD with a rapid and cheap iterative refinement process. Combining the high order hierarchical basis functions with MMLCBD can make good use of their …respective advantages to analyze the large-scale electromagnetic problems efficiently. The numerical results demonstrate that the proposed method is much more efficient than conventional MLCBD for analyzing the large-scale electromagnetic problems. Show more

Keywords: Multilevel compressed block decomposition (MLCBD), high order hierarchical basis functions, direct solution

DOI: 10.3233/JAE-170035

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 167-175, 2017

Authors: Codecasa, Lorenzo | Di Rienzo, Luca

Article Type: Research Article

Abstract: An approach to quantify uncertainty in linear three-dimensional magnetostatic problems with correlated random reluctivities is proposed. Such strategy is based on a reduced-order model and a spectral approximation of the deterministic parametric magnetostatic problem for accurately and efficiently estimating the statistics of the quantities of interest.

Keywords: Uncertainty quantification, magnetostatics, finite integration technique

DOI: 10.3233/JAE-170063

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 1, pp. 177-183, 2017