International Journal of Applied Electromagnetics and Mechanics - Volume 39, issue 1-4

Authors: Yamaguchi, Tadashi | Kawase, Yoshihiro | Suzuki, Satoshi | Koyanagi, Wataru | Hirata, Katsuhiro | Ota, Tomohiro

Article Type: Research Article

Abstract: Recently, miniature electromagnetic relays are required to have high reliability. The reliability of the relay is lost by numerous collisions of a contact. Therefore, we calculate the collision energy of a miniature electromagnetic relay with a permanent magnet through the dynamic characteristics analysis using the three-dimensional finite element method (3-D FEM). The effects of the material of the armature and the number of coil turns on the collision energy are numerically clarified.

Keywords: Finite element method, electromagnetic relay, collision energy

DOI: 10.3233/JAE-2012-1525

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 657-664, 2012

Authors: Renhart, Werner | Magele, Christian | Brandstätter, H. | Koplenig, M. | Scharrer, G. | Heubrandtner, T. | Prochazka, W.

Article Type: Research Article

Abstract: The performance of Li-ion batteries under variant operating conditions requires a highly developed battery management. In attaining this a very accurate knowledge of the temperature profile within the cells is of great importance. This contribution deals with the numerical approximation of the temperature behaviour as well as of the heat sources caused by the current flow inside the battery. Thereby a coupled electro-thermal finite element based computation scheme will be applied.

Keywords: Li-ion batteries, current flow, thermal problem, finite elements

DOI: 10.3233/JAE-2012-1526

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 665-669, 2012

Authors: Watanabe, Kota | Watanabe, Yuta | Igarashi, Hajime | Waki, Hiroshi

Article Type: Research Article

Abstract: This paper proposes double antennas which consist of receiver and backscatter antennas for passive long range UHF-band IC (Integrated Circuit) tags. The passive IC tags reply to reader's queries by using backscatter modulation. For this purpose, variable impedance elements are inserted between the antenna and a voltage multiplier which generate dc power. This decreases the efficiency of received power in the voltage multiplier and reduces the communication range. To solve this problem, we propose to use …an independent antenna for backscatter modulation. Experimental results and numerical simulation results show that the double antennas successfully reply data from IC tag to the reader. Show more

Keywords: Antenna, backscatter, FDTD, RFID

DOI: 10.3233/JAE-2012-1527

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 671-676, 2012

Authors: Kiss, Imre | Benkö, Péter Tamás | Gyimóthy, Szabolcs

Article Type: Research Article

Abstract: In this paper a modeling technique enabling the fast analysis of antenna arrangements built-up from metallic parts is presented in detail. A calculation method which accelerates the solution of integral equations discretized by the Method of Moments have been implemented in a massively parallel computing environment, a general purpose video card (GPU). Rao-Wilton-Glisson edge basis functions are used to expand surface currents, while radiated field is computed using the dipole model. Since the entire …computation takes place on the GPU exclusively, the overall computational time could be significantly reduced. To obtain such an acceleration, a novel computational technique is proposed for the filling of the impedance matrix, which takes full advantage of the given platform. Show more

Keywords: CUDA, GPU computing, optimal filling, parallel MoM

DOI: 10.3233/JAE-2012-1528

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 677-683, 2012

Authors: Di Barba, Paolo | Savini, Antonio

Article Type: Research Article

Abstract: An approach based on the use of Thévenin-like conditions, in order to define a reduced domain for finite-element analysis (FEA), is proposed to help the solution of optimal synthesis problems in a cost-effective way. In particular, the mismatch of nodes discretizing the common boundary between reduced and complementary domain is considered. A case study in 2D magnetostatics, where the field domain is an open-boundary region, is considered.

Keywords: Optimal shape design, field diakoptics, finite element analysis, generalized Thévenin theorem

DOI: 10.3233/JAE-2012-1529

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 685-691, 2012

Authors: Ceclan, Andrei | Ţopa, Vasile | Micu, Dan D. | Czumbil, Levente | Şimon, Anca | Creţ, Octavian

Article Type: Research Article

Abstract: This paper presents an alternative framework for computing the electric potential in (non)homogeneous media using a Monte Carlo-based method. The implementation relies on the use of FPGA to improve the computational speed. Compared to the previous software implementations, this approach allows increasing the variation range of all parameters involved in the computation, thus yielding more accurate and faster results. The obtained computation time is more than one order of magnitude less than classical software solutions.

Keywords: FPGA, Monte Carlo, numerical analysis, computational speed-up

DOI: 10.3233/JAE-2012-1530

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 693-698, 2012

Authors: Ohji, Takahisa | Miao, Zhen | Matsushima, Koji | Amei, Kenji | Sakui, Masaaki

Article Type: Research Article

Abstract: This paper describes the operating state improved by using phase-advanced capacitors for the ac induction type magnetic levitation (maglev) system. In case many coils are set up in yoke such as this type of maglev, the impedance of electric circuit of the stator has strong inductivity; therefore, a phase-advanced capacitor should be inserted to achieve power-saving operation for the inductive circuit. However, the ferroresonance state occurs as the power-factor of the circuit approaches 1, and then …the current steeply increases even if the voltage increases slowly. Thereby, a non-magnetic plate greatly oscillates when it starts to levitate. To improve the starting oscillation, we adopted the method of switching two different capacitors. As a result, both smooth starting of levitation and minimum input power operation functioned successfully. Show more

Keywords: Ac induction type maglev, phase-advanced capacitor, power-factor correction, ferroresonance

DOI: 10.3233/JAE-2012-1531

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 699-704, 2012

Authors: Cundeva-Blajer, Marija | Arsov, Ljupco

Article Type: Research Article

Abstract: In the paper an analysis of the influence of the objective function during the process of metrological optimal design of an electromagnetic measurement system is made. The case study is a combined measurement transformer. The optimal design of the transformer is made by using an original program based on the genetic algorithm. Four different objective functions comprising the main metrological parameters of the transformer (voltage and phase displacement error of the voltage measurement core and current …and phase displacement error of the current measurement core) are posed for the optimal design. Two metrological approaches are embedded in the objective functions: 1) the conservative (with certain measurement errors) and 2) the Guide EA-4/02 "Expression of the Uncertainty of Measurements in Calibration" (GUM) statistical approach. The optimal design solutions derived for the different objective functions are compared and discussed. Show more

Keywords: Instrument transformer, genetic algorithm, design of electromagnetic system, objective function

DOI: 10.3233/JAE-2012-1532

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 705-710, 2012

Authors: Ishibashi, Kazuhisa | Andjelic, Zoran | Takahashi, Yasuhito | Takamatsu, Tomoaki | Tsuzaki, Kenta | Wakao, Shinji | Fujiwara, Koji | Ishihara, Yoshiyuki

Article Type: Research Article

Abstract: The volume integral equation approach replaces magnetic materials with the magnetization in magnetostatic analysis. The concept of magnetic shell relates the magnetization with loop currents. The loop current is equivalent to the magnetic double layer, which gives an integral form of the scalar potential. The nonlinear magnetic field is formulated by regarding the nonlinear magnetization as volume magnetic charges. This paper presents how to utilize the volume charge to solve nonlinear problems. In the case of …constant volume element we replace the volume charges with the surface loop currents to derive the nonlinear boundary integral equations having the line and surface loop currents as unknowns. The boundary integral equation is solved iteratively while improving alternately the loop and surface currents. Show more

Keywords: Boundary integral equation, loop currents, magnetic charges, magnetic double layer, nonlinear magnetostatic analysis

DOI: 10.3233/JAE-2012-1533

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 711-717, 2012

Authors: Wang, Cheng | Bai, Junqing | Li, Jiaojiao | Dong, Longlei | Yan, Guirong | Sun, Zengguo

Article Type: Research Article

Abstract: In order to overcome the problem of classical K-means clustering algorithm, such as sensitiveness to its initial cluster centers selection and easiness of falling into local optimization, this paper proposed max-min K-means clustering algorithm. The algorithm adopts max-min principle to determine initial cluster centers of K-means clustering algorithm. Comparison of clustering effects of the new method with that of muilt-restart K-means clustering algorithm on artificial data set showed the better effect and the …greater excellence of max-min principle. Then, the max-min K-means clustering algorithm was applied to analyze vibration response signal of cylindrical shell automatic in order to discover space distribution feature of dynamics response. Clustering results tallied with feature of dynamic response of cylindrical shell, which validated the effectiveness and reasonableness of the new clustering method itself. Show more

Keywords: Signal feature extraction, clustering, K-means, max-min

DOI: 10.3233/JAE-2012-1534

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 719-724, 2012