International Journal of Applied Electromagnetics and Mechanics - Volume 58, issue 2

Authors: Zheng, Li | Wei, He | Lingqi, Liu | Qunjing, Wang

Article Type: Research Article

Abstract: In this paper, a new type of permanent magnet type 3-DOF hybrid driven motor is proposed in view of the poor precision of existing deflection movement control and low speed of multi-degree-of-freedom motor rotation. The motor contains two part named lateral rotation module and internal deflection modules. The output torque of the motor, the rotation speed and control precision are improved by the coordinated control of rotation movement and deflection movement. The magnetic field shielding and optimization of two modules inside and outside the motor are realized by using Halbach permanent magnet array, and the magnetic field characteristics of the …motor are improved. First, using analytical method and finite element method, the magnetic field characteristics and distribution of the permanent magnet of the motor are analyzed, and the electromagnetic characteristics of load and no load condition and output torque of the motor is analyzed by finite element method. Then, the loss of this motor is analyzed and calculated, the motor response surface equation is built by using taguchi method and central composite design method. Finally, the optimal structure parameters of motor is proposed by the numerical model based on maximizing the motor output torque of the target, and it is compared with finite element and experiment to verify the accuracy of the structural parameters. It provides a new theoretical basis for the follow-up optimization of the motor. Show more

Keywords: 3-DOF motor, Halbach array, permanent magnet, magnetic field calculation, torque, structure optimization, taguchi method

DOI: 10.3233/JAE-180058

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 121-155, 2018

Authors: Zhan, Jiawen | Lu, Qinfen

Article Type: Research Article

Abstract: In order to reduce the transverse edge effect of linear induction motors (LIMs) for low-speed Maglev train, this paper proposes a novel single-sided LIMs (SLIMs) with V-shaped ladder-slit secondary. Firstly, the topology of this SLIMs is introduced based on the erected 3-D finite element model. Secondly, for the V-shaped ladder-slit secondary, the effect of slot combination is investigated, and then the secondary is optimized by a single-parameter optimization method, including the width of secondary side-bars, secondary slot width, transverse width of secondary slits and the skew angle of V-shaped slits. Thirdly, the air gap flux density, eddy current, thrust force …and normal force of this SLIMs are calculated, respectively. By comparing to those of two SLIMs with available double ladder-slit and cap-solid secondary, the results show the proposed novel SLIMs can improve the performance due to effectively reducing the transverse edge effect. Finally, to the proposed SLIMs, the effect of the middle bar in V-shaped ladder-slit secondary is studied. It is found that adopting middle bar can improve the performance and increase the mechanical strength, which is more suitable for low-speed Maglev train. Show more

Keywords: Double ladder-slit secondary, linear induction motor, low-speed Maglev train, optimization design, edge effect, V-shaped

DOI: 10.3233/JAE-180036

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 157-174, 2018

Authors: Zou, Fangli | Huang, Shangyu | Lei, Yu | Zhang, Jifa | Zhou, Mengcheng | Yan, Shiwei | Feng, Fei

Article Type: Research Article

Abstract: Weight reduction is a primary concern in the automotive and electrical industries because of the intensive requirements of energy conservation and emission reduction. As the lightest structural metal, magnesium (Mg) alloys are widely used in the automotive and aerospace industries. However, the current industrial application of this material is mainly limited to pressure casting parts due to its poor formability at room temperature. Therefore, identifying the factors that affect the formability of Mg alloy is highly important. In this study, forming limits of Mg alloy sheet under electromagnetic forming (EMF) condition were analyzed at different temperatures based on the Johnson–Cook …constitutive model and the failure model. The complete forming limit diagrams of AZ31 Mg alloy at different temperatures and high strain rates were established. The effects of voltage, capacitance, and temperature on the forming limit of AZ31 Mg alloy under EMF were systematically investigated. Results showed that increased discharge voltage and temperature can effectively improve the EMF limit of Mg alloy. The effect of increasing capacitance on the formability of Mg alloy was not obvious. Show more

Keywords: AZ31 magnesium alloy, electromagnetic forming, warm forming, high strain rates, forming limit diagrams

DOI: 10.3233/JAE-180028

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 175-192, 2018

Authors: Zhao, X. | Liu, J. X. | Qian, Z. H. | Gao, C. F.

Article Type: Research Article

Abstract: The fracture behaviors of a piezoelectric-piezomagnetic sandwich structure with an eccentric internal crack subjected to two kinds of in-plane electromechanical loads have been studied in this paper. A singular integral equation with Cauchy kernel is obtained by means of Fourier transform and further solved by using Gauss-Chebyshev technique. Then the stress intensity factors are obtained and some numerical results are presented to show the effects of the material properties, structure geometries, electromechanical loads and the crack location on the stress intensity factors. The conclusions of the present paper may be useful for the design and fracture prediction of layered piezoelectric-piezomagnetic …structures. Show more

Keywords: Piezoelectric-Piezomagnetic composite, sandwich structure, plane strain problem, integral transformation, stress intensity factor

DOI: 10.3233/JAE-180039

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 193-214, 2018

Authors: Jun, Zhu | Dandan, Song | QiaoLi, Han | Shaolong, Li | Jinmei, Wang | Guanghuai, Li | Di, Cao

Article Type: Research Article

Abstract: In order to improve the suspension characteristics of passive magnetic bearings in vertical axis wind power generation system, T-shaped group of passive magnetic bearing with three rings which owns high suspension characteristics are proposed. The working principle of the structure is described briefly. The multi-objective optimization is achieved with high bearing capacity and high magnetic stiffness by studying its impacts on the magnetic ring with variable geometric parameters: the height of the magnetic ring, the thickness of the magnetic ring and the air gaps between the magnetic rings. The research shows that suspension characteristics of the novel structure are 2 …times of the traditional radial magnetic bearings. Its the bearing capacity is at least 1.75 times before optimization and the magnetic stiffness is at least twice as high as before optimization which provides a reference for the suspension characteristics of the vertical axis wind turbine suspension system. Show more

Keywords: Vertical axis, high magnetic stiffness, high bearing capacity, suspension characteristics

DOI: 10.3233/JAE-180020

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 215-226, 2018

Authors: Kim, Ki-Hoon | Jeong, Byung Hwan | Woo, Dong-Kyun

Article Type: Research Article

Abstract: In this paper, the overhang structure, which has been used in the radial flux permanent magnet motor, was applied to the axial flux permanent magnet (AFPM) motor. Moreover, the overhang effect was investigated for different overhang structures. Because the AFPM motor has an enlarged form along radial direction, the leakage flux and the saturation effect are considerably different at inner and outer radius of the stator. Therefore, inner and outer overhang part could have different overhang effects. This can lead to the optimization problem with optimal overhang length. Because the AFPM motor requires 3D finite element analysis from its 3D …structure, an efficient optimization algorithm is required for optimal overhang structure. In order to increase the convergence speed of the optimization algorithm, this paper proposed the gradient assisted contour method. Show more

Keywords: Axial flux permanent magnet motor, finite element method, overhang effect, overhang structure

DOI: 10.3233/JAE-170158

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 227-237, 2018

Authors: Díaz Flórez, Guillermo A. | Mombello, Enrique E. | Marulanda, Geovanny A.

Article Type: Research Article

Abstract: Power transformer design normally includes an optimization process which involves the assessment of a great number of design alternatives. This calculation process normally requires a high computation time and its reduction is always a desirable goal. Circulating currents in parallel connected conductors in transformer windings are a critical design aspect to be analyzed. This article presents a new methodology for the fast calculation of circulating currents for parallel connected conductors in power transformers. The formulation for solid conductor modeling has been developed using the same calculation strategy as in Semianalytic Integral Method (SAIM) [1 ], which allows a significant reduction …of computational effort. A realistic case study of a 25 MVA transformer was used to validate the proposed methodology. As for the accuracy of the calculations, the comparison of the results obtained by the proposed methodology and those calculated using the Finite Element Method (FEM) shows an excellent agreement between both approaches. However, the computational performance of the new approach was found to be much higher than that of FEM. This makes the proposed method much more efficient for transformer design purposes. Show more

Keywords: Circulating currents, power transformers, integral methods, skin depth

DOI: 10.3233/JAE-170034

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 239-260, 2018

Authors: Zhang, Pengning | Li, Lin | Zhang, Juanjuan | Gao, Chong

Article Type: Research Article

Abstract: The vibration and noise produced by the anode saturable reactor (ASR) in the HVDC transmission converter valve are very serious, and the long-term vibration can accelerate the aging of the equipment and damage the friendly environment. In this paper, a core with race-track shape from the ASR in ±800 kV/4750 A project is used as the research object. An excitation winding is wounded on the core, and the vibrations and noises are measured when the winding is excited respectively by sine wave and rectangular waves at different frequencies. In order to reduce the noise, the polyurethane damping elastomer is filled …into the box of core, and the vibrations and noises of core with polyurethane damping elastomer under different excitations are measured. The results show that the polyurethane damping elastomer can efficiently reduce the vibrations and noises of the anode saturated reactor core, especially under non-sinusoidal excitation. This research is of significant reference value for the vibration and noise reduction of ASR and other high frequency equipment. Show more

Keywords: Anode saturable reactor, vibration, noise, damping elastomer

DOI: 10.3233/JAE-180050

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 2, pp. 261-273, 2018