International Journal of Applied Electromagnetics and Mechanics - Volume 61, issue 1

Authors: Cheng, Yuhua | Qian, Gaorong | Chen, Guoxiong | Sun, Haoran | Wang, Gaofeng

Article Type: Research Article

Abstract: L-type impedance matching circuits (IMCs) can maximize the power transfer efficiency (PTE) by converting the load to the optimum one in the wireless power transfer system. However, their effectiveness is inadequately studied. In this work, the applicability of the L-type IMCs is carefully examined under the restriction of capacitance realization. The sensitivities with respect to the deviation of the capacitance in mass production as well as the variations of the load and the mutual inductance are analyzed in detail and validated by experiments. By comparison with the basic-type IMCs, the L-type IMCs have higher, nearly equal and lower sensitivities with …respect to the deviation of the capacitance, the variation of the load, and the variation of the mutual inductance, respectively. Show more

Keywords: L-type impedance matching circuit, sensitivity, power transfer efficiency

DOI: 10.3233/JAE-180089

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 1-11, 2019

Authors: Zhang, Pengfei | Wang, Zhiheng | Xi, Guang

Article Type: Research Article

Abstract: This paper proposes a general multi-objective optimal design methodology for a new type of no-thrust-disk/thrust hybrid magnetic bearing that has been designed to reduce wind loss in centrifugal compressors. The approach dispenses with initial design results and has adjustable design objectives. To establish the proposed method we begin with its conceptual design, then look at how a parametric geometric model can facilitate manufacture, installation and cooling, before presenting a magnetic circuit model that can take into account eddy-current effects and significant magnetic leakage. The key optimization objectives selected include bearing capacity, mass, axial length, copper loss, iron loss, wind loss, …and outer diameter. The approach also takes into account the performance deterioration of permanent magnets at high temperatures. By using an optimization method that combines penalty factor and selection factor, we have been able to incorporate a function for adjusting and re-adjusting the optimization goals. To verify the validity of the approach we present a concrete design case. Out of four possible schemes, a scheme based on minimum mass and axial length proves to be the best solution in this example (assuming sufficient cooling capacity). Show more

Keywords: Thrust hybrid magnetic bearings (THMB), equivalent magnetic analysis, multi-objective optimization (MOO), eddy-current effect, wind loss

DOI: 10.3233/JAE-180062

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 13-42, 2019

Authors: Wajnert, Dawid

Article Type: Research Article

Abstract: A hybrid magnetic bearing (HMB) with six poles is an effective construction of the magnetic bearing. It is energy efficient due to the presence of permanent magnets and it can be supplied from a three phase inverter. Unfortunately, the cross-coupling effect and nonlinearity of magnetic force occur in the 6-pole construction of the HMB. The purpose of this paper is to investigate the cross-coupling effect and nonlinearity of magnetic force as well as to propose two methods of reducing them. The proposed methods include division of the stator joke into three parts and exciting an additional current in one winding. …Presented HMB was analysed with the 3D finite element method. The numerical model was verified by measurement. Show more

Keywords: Hybrid magnetic bearing, electromagnetic calculations, cross-coupling effect, magnetic nonlinearity

DOI: 10.3233/JAE-180088

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 43-57, 2019

Authors: Martinez-Muñoz, Miriam | Diez-Jimenez, Efren | Sanchez-Montero, Rocio | Lopez-Espi, Pablo Luis | Martinez-Rojas, Juan Antonio

Article Type: Research Article

Abstract: Magnetic actuators, magnetic gears, vibrational energy harvesters and other micro-electromagnetic devices requires micro-magnetic rotors with alternant magnetizations to optimize their performance. Different approaches have been used for multipole magnetization of micro-magnets like fixed micro-fixtures, thermomagnetic patterning or laser machining. The main limitation of the previous techniques is that the inversion of the magnetic polarizations is only partially done. In this work, a concept based on 2D multipole magnetization printing of micro-magnets is proposed and analyzed to overcome current limitations. The fixtures are designed to be printed on a standard 35 μm PCB. The dependence of the magnetizing field with respect …to the geometrical parameter of the fixture is analyzed. Maps of the required current for the magnetizing fields are also given. Some design recommendations to optimize the magnetizing field and to minimize current, thus the heat, are given. Show more

Keywords: Magnetizing fixtures, magnetic polarization patterning, micro-magnets

DOI: 10.3233/JAE-180121

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 59-71, 2019

Authors: Aguib, Salah | Nedjar, Ali | Zerrouni, Nassim | Djedid, Toufik | Tourab, Mohamed | Guedifa, Réda

Article Type: Research Article

Abstract: This paper is devoted to an experimental and theoretical study of the magneto-mechanical behavior of an elastomer loaded with 25% of ferromagnetic particles of micrometric size; elaborated under the action of a magnetic field. The characterization of the rheological properties and the interaction between the micron size ferromagnetic particles as a function of the intensity of the magnetic field are studied. The results obtained clearly show a high energy dissipation properties of the composite, accentuated by its modified structure from the interaction forces between the particles that are aligned, which gives adjustable viscoelastic structures properties, depending on the volume fraction …of particles and the magnetic field intensity. Show more

Keywords: Magneto-mechanical behavior, micrometric particles, rheological properties, magnetic force, elastomer

DOI: 10.3233/JAE-180108

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 73-85, 2019

Authors: Shi, Minxia | Zhang, Xuanrui | Qiu, Aici | Li, Junhao

Article Type: Research Article

Abstract: As the core material of electrical equipment, electrical steel sheet is often under rotational magnetization and DC-biased magnetization simultaneously. The rotating magnetic flux density, rotating magnetic field strength and total iron loss density under various DC-biased magnetizing condition are measured and analyzed in this paper to investigate the effects of DC magnetizing angle and amplitude on rotating magnetic properties. An improved model considering saturation and hysteresis is established for describing the rotating magnetic properties of electrical steel sheet under DC-biased field based on experimental results. It can be concluded that offset and distortion of the rotating magnetic parameters loci occur …with the increase of DC-biased magnetization. When the electrical steel sheet is magnetized to deep saturation, the total loss density decreases due to the diminishment of magnetic domain walls. The impact of DC-biased excitation on rotating properties is most obvious in hard magnetization direction. Show more

Keywords: Electrical steel sheet, DC-biased magnetization, rotating magnetic properties, iron loss density

DOI: 10.3233/JAE-180125

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 87-96, 2019

Authors: Tang, Mingdong | Gu, Youlin | Wang, Shigang | Liang, Qinghua | Wang, Xiaoxi

Article Type: Research Article

Abstract: With the popularization of intelligent substations, hot-line working robots that can replace the manual operation without shutting down the power of the corresponding equipments are increasingly widely applied in the maintenance and monitoring of substations. Robotic operation can ensure the safety of the operators and reliability of operation while improving the economic benefits of substation. However, because of the compact structure of the intelligent substations, the operating space is small. Further, as the main material of hot-line working robots is metal, which greatly changes the strength and distribution of the electric field around its working position when entering the working …position and in the process of operation. In serious cases, interphases or phase to ground air breakdown occurs. Hence the working space of hot-line working robots is limited not only by the narrow space between devices in the substation but also by the electrical safety clearance of phase to phase and phase to ground. Therefore, it is necessary to find a safe working space (“SWS”) for the robot which should not be too small for the robot to accomplish the task effectively. The purpose of this paper is to provide: (i) a design reference for hot-line working robots which can not only guarantee the electrical safety distance but also minimize the effect to the electric field and (ii) a method to find the SWS of the robot in which the robot can accomplish the task effectively with the example of the hot-line working robot for isolated circuit breaker (“ICBot”). We analyze the influence of different installation positions and postures of the manipulators on the electric field in this paper and present a calculation method of the SWS of the manipulator in a very non-uniform electric field caused by the intervention of manipulators, which is significant to the research on hot-line working robots. The SWS has been tested in simulated and energized experimental system, and the experiment results show that the robot can work safely and efficiently. Show more

Keywords: Hot-line robot, electric field distortion, air breakdown, substation insulation

DOI: 10.3233/JAE-180057

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 97-110, 2019

Authors: Liao, Yaoyao | Lian, Zisheng | Yuan, Hongbing | Feng, Jiling | Cui, Hongwei

Article Type: Research Article

Abstract: The solenoid valve used on the hydraulic roof support in the coal mine is an intrinsically safe solenoid. It requires the solenoid valve to achieve large electromagnetic force at low current. The load can not be driven if the current is too low, while a large temperature rise and energy loss would occur in the form of heat if the current is too high. In order to solve this contradictory problem, the load force of the solenoid valve was analyzed first. Then the ANSYS models of the solenoid were established to carry out the simulation jobs. The effects of the …three parameters, the sleeve length, the seat length and the boss height, on the electromagnetic forces and magnetic fields were researched so as to optimize the three parameters. The static and dynamic characteristics of the optimized solenoid valve were also studied. An experimental setup was established to verify the simulation results finally. Results show that the simulation values are in good agreement with the experimental values. The peak value of starting current and holding current is small and the solenoid responses rapidly. This study proves the accuracy and reliability of the simulation models and the methods. It also provides valuable references for the design and optimization of the intrinsically safe solenoid valve. Show more

Keywords: Solenoid, electromagnetic force, magnetic field, ANSYS, hydraulic roof support

DOI: 10.3233/JAE-190011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 111-122, 2019

Authors: Guo, Liang | Lu, Wenqi | Cai, Junjun

Article Type: Research Article

Abstract: Double-sided air-cored tubular generators (DSTG) have higher power density than traditional air-cored generators, and are desirable for applications in renewable energy conversion systems. In order to achieve best power quality and maximum efficiency with minimum cost, multi-objective optimization of the DSTG is carried out. Aim to decrease the computational time and guarantee the accuracy of the multi-objective optimization of DSTGs, a new integrated modeling method is proposed and focused in this paper. The new modeling method integrates the analytical models and the machine learning models together. The experimental results prove that the new integrated model can provide higher accurate calculation …results than analytical models and need fewer samples than machine learning models. The optimization time needed by the new model is 5 times shorter than that needed by the FE model. Show more

Keywords: Double-sided tubular generator, machine learning, multi-objective optimization

DOI: 10.3233/JAE-190015

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 123-135, 2019

Authors: Ouili, Mehdi | Mehasni, Rabia | Feliachi, Mouloud | Belounis, Abdallah | Latreche, Mohamed El Hadi

Article Type: Research Article

Abstract: The aim of this work is the investigation of the simultaneous separation of magnetic (𝜇r > 80) and conductive (𝜎 ≈ 6 ×107  S/m) particles in a designed magnetic separator. Such a separator consists mainly of a drum on which permanent magnets are arranged and a conveyor belt carrying the material to be purified. The separately driving of the drum and the conveyor belt allows the independent control of the frequency of the generated magnetic field and the displacement speed of the material to be treated. To generate high magnetic field, identical NdFeB permanent magnet bars with residual magnetic flux …density B r = 1.2 T are used. To compute the particles trajectories, the magnetic field and the particle dynamic governing equations have been solved using the numerical finite element (FEM) and Runge Kutta (RK4) methods. The computing results have shown that the proposed separator permits the simultaneous separation of magnetic and conductive particles. To check the validity of the numerical results, experiments have been carried out on ferromagnetic powder and conductive particles of different sizes. Show more

Keywords: Magnetic separation, drum, particle trajectories, finite element, permanent magnets

DOI: 10.3233/JAE-180101

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 1, pp. 137-155, 2019