International Journal of Applied Electromagnetics and Mechanics - Volume Pre-press, issue Pre-press

Authors: Aguilar, Arturo | Rubio, José de Jesús | Meda-Campaña, Jesús A. | Martinez, Dany Ivan | Vargas, Tomas Miguel | Garcia, Victor | Novoa, Juan Francisco | Mujica-Vargas, Dante | Pacheco, Jaime | Gutierrez, Guadalupe Juliana

Article Type: Research Article

Abstract: In this article, the mathematical model of a machine with eight immovable magnets and two movable magnets, and the machine with four immovable magnets and two movable magnets are introduced for the electricity creation. The proposed machines are based on the machine with two immovable magnets and two movable magnets, but they have two main differences: they have more interactions between the immovable and movable magnets, and they create more electricity. Experiments are included to validate that the proposed mathematical models represent a prototype and to observe which machine creates more electricity.

Keywords: Machines, immovable magnets, movable magnets, electricity creation, mathematical models

DOI: 10.3233/JAE-190087

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-20, 2020

Authors: Wang, Shaopeng | Ma, Jinguang | Liu, Chengcheng | Wang, Youhua | Lei, Gang | Guo, Youguang | Zhu, Jianguo

Article Type: Research Article

Abstract: To improve output torque ability and reduce torque ripple in traditional synchronous reluctance motor (TSynRM), a new synchronous reluctance motor (NSynRM) is proposed in this paper. The rotor of NSynRM is composed of both grain-oriented silicon steel and non-oriented silicon steel. With the reasonable design of rotor structure, the torque of NSynRM has been improved and its torque ripple has been reduced greatly. Firstly, TSynRM and NSynRM are qualitatively compared by using the magnetic network method. Secondly, the main parameters of these two machines are optimized by using finite element method (FEM). Then the performance comparison between two optimized machines …are carried out. Finally, the equivalent stress of these two machines at the maximum speed are analyzed. It can be seen that NSynRM can have 6.8% higher torque under rated load, 8% higher torque under maximum load, 17.5% wider constant torque operation region, and lower torque ripple compared with the TSynRM. Show more

Keywords: Synchronous reluctance machine, grain-oriented silicon steel, reluctance torque, magnetic network analysis, finite element method

DOI: 10.3233/JAE-190109

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-17, 2020

Authors: Shen, Sheng | Wu, Jiamin | Guo, Pan | Wang, Hongyi | Chen, Fangge | Meng, Fanqin | Xu, Zheng

Article Type: Research Article

Abstract: Comparing with superconducting and permanent magnet magnetic resonance imaging (MRI) system, ultra-low- field MRI (uMRI) system has a much lower weight, which can be used in some special scenes, such as real-time image monitoring on bedside or in the ambulance for human brain disease (stroke). In order to make the uMRI system more compact, lighter, and smaller, in this work, we proposed a hybrid method for designing uMRI electromagnet. The method consists of integer linear programming (ILP) and nonlinear optimization, which were bridged by empirical principles. ILP was used to determine the coil distribution of uMRI electromagnet. Considering that the …coil distribution, acquired with ILP, is not conducive for magnet processing, two empirical principles were applied to adjust the coil distribution with decreasing electromagnet performance as little as possible. At last, nonlinear optimization was exploited to eliminate the negative influence on magnetic field distribution which is introduced by coil adjustment and make electromagnet satisfy the design requirement of magnetic field homogeneity. This hybrid method combines mathematical models and empirical principles, which provides a way to design electromagnet efficiently. A small electromagnet with homogeneity of 10 ppm in a sphere region of interest (ROI) with diameter of 80 mm is designed and built in this paper. Show more

Keywords: Ultra-low-field MRI, electromagnet design, integer linear programming, nonlinear optimization

DOI: 10.3233/JAE-190051

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-12, 2020

Authors: Bu, Wenshao | Tu, Xiaowan | Lu, Chunxiao | Pu, Yi

Article Type: Research Article

Abstract: In order to solve the unbalanced vibration problem of bearingless induction motor caused by the rotor mass eccentricity, an adaptive feedforward vibration compensation control strategy is researched. Firstly, the inverse dynamic decoupling control method of torque system and the steady-state stochastic displacement feedback control of magnetic suspension system are introduced in brief. Then the feedforward compensation control strategy of unbalanced vibration displacement is discussed, taking the minimum mean square error of rotor radial displacement as a goal, an adaptive feedforward compensation control algorithm for unbalanced vibration displacement is designed, and by changing the amplitude and phase of the compensation signal …of unbalanced vibration displacement step by step iteratively, the influence of periodic unbalanced excitation force is suppressed or counteracted. Finally, the feedforward compensation control method is simulated and validated, and the influence of the detection deviation of motor speed on the vibration compensation effect is analyzed. The simulation experiment results show that the adaptive feedforward vibration compensation control strategy can significantly suppress the unbalanced vibration displacement during the sudden change of motor speed, and can eliminate the unbalanced vibration displacement in the steady state, and then the suspension control accuracy of the rotor is greatly improve. Show more

Keywords: Bearingless induction motor, unbalanced vibration displacement, adaptive feedforward vibration compensation, step by step iteratively

DOI: 10.3233/JAE-190092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-17, 2020

Authors: Si, Zhanchao | Yang, Fan | Yao, Degui | Zhang, Guangzhou | Kou, Xiaoshi | Gao, Bing | Feng, Zhihui

Article Type: Research Article

Abstract: The UHV transmission lines usually have large regional spans and involve various weather conditions, which will have different effects on the circuit design and electromagnetic environment. However, the existing research lacks the ion flow field analysis of AC and DC parallel lines under different weather conditions. Hence, we studied the distribution law of the ion flow field of ±800 kV DC and 500 kV AC parallel transmission lines under different weather conditions, and compared the calculated results with measured results. First, we used the meshless method to model the ion flow field of AC and DC parallel lines in different weathers. Then, …the influence of environmental factors on the ion flow field was analyzed. The effects of temperature, humidity and haze on the distribution of the ion flow field were obtained based on long-term monitoring and measurement. Results show that the ion flow field of the theoretical calculation results was basically in accord with the actual measurement. The ion flow field of parallel lines increases with the rise of temperature, first increases and then decreases with the rise of humidity, and increases with the rise of haze. Show more

Keywords: Ion flow field, weather conditions, parallel lines, meshless method

DOI: 10.3233/JAE-190113

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-12, 2020

Authors: Qiu, Li | Deng, Kui | Li, Yantao | Tian, Xi | Xiong, Qi | Chang, Peng | Su, Pan | Huang, Lantao

Article Type: Research Article

Abstract: The long-life driving coil is the prerequisite for electromagnetic forming industrial application. Up to date, the temperature rise is one of the major factors that restrain its working life. For the purpose of reducing the temperature rise of the driving coil, this paper proposes a new coupled cooling method, in which an extra cooling coil is placed on one side of the driving coil, then the Joule heating is coupledly transferred by delaying the breakover control of the driving coil. To achieve this purpose, a finite element simulation model of Electrical Circuit- Electromagnetic Field-Thermal Coupling in the plates setting of …the electromagnetic forming is established, after which the influence rules of coil turns, cross-sectional area and materials of cooling coil on temperature rise are analyzed. Then, this paper also establishes a coupled cooling circuit model, in which the influence of cooling coil structure parameters on the Joule heating of driving coil is analyzed. Furthermore, Simulation results show that effective Joule heating transfer can be reached by the best optimization scheme of the cooling driving coil. Specifically, the average temperature rise reduces by 13 degrees, namely 22.8% by using this new method. Show more

Keywords: Electromagnetic forming, driving coil, temperature rise, Joule heating

DOI: 10.3233/JAE-190062

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-14, 2020

Authors: Zhang, Yunfeng | Gu, Jialiang | Zhang, Erchun

Article Type: Research Article

Abstract: Studying underground propagation effects of lightning electromagnetic fields in different geological environments will contribute to more reasonable designs for protecting underground cables and electronic equipment. In this paper, we have analyzed influences of different geological environments, depths and soil water content on underground propagation of lightning electromagnetic fields in detail by using the nite difference time domain (FDTD) method in the 2-D cylindrical coordinate system to calculate components of underground electromagnetic fields at a horizontal distance of 200 m, including vertical electric field E z , horizontal electric field E r and azimuthal magnetic field H 𝜑 …. The results show that the underground electric field is predominantly horizontal. Propagation of lightning electromagnetic fields in wet clay and wet limestone environment changes significantly compared to freshwater environment. Attenuation is larger with depth in wet clay and wet limestone, while propagation is unaffected in freshwater. When water content in soils ranges from 5% to 25%, the vertical electric field has the largest attenuation and the azimuthal magnetic field has the least attenuation. The electromagnetic fields in clay are most sensitive to changes in water content. Show more

Keywords: FDTD, lightning electromagnetic fields, different geological environments, water content, underground propagation

DOI: 10.3233/JAE-190112

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-13, 2020

Authors: Yang, Xiaolong | Sun, Peng | Hao, Fuxiang

Article Type: Research Article

Abstract: In order to improve the pressure capability of the ferrofluid seal under the condition of large sealing gap, a diverging stepped ferrofluid seal with a large gap and two magnetic sources was designed. The magnetic field distributions in the gap of the ferrofluid seal were calculated by finite element method. The effects of the pole teeth number, the height of the pole teeth and the sealing gap on the pressure capabilities of the diverging stepped ferrofluid seal are studied and compared with ordinary ferrofluid seal. The results show that the change of the radial pole teeth number has little effect …on the pressure capability of the stepped ferrofluid seal. The pressure capability of stepped ferrofluid seal decreases with the increase of the axial pole teeth number. The pressure capability of the stepped ferrofluid seals reach maximum when the radial and axial pole teeth height is 0.6 mm. The pressure capability of stepped ferrofluid seal decreases as the radial sealing gap increases. The pressure capability of stepped ferrofluid seal decreases firstly and then increases with the increase of the axial sealing gap. Comparing with ordinary ferrofluid seal, the stepped ferrofluid seal has better pressure capability. Show more

Keywords: Large gap, diverging, ferrofluid, seal, numerical simulation

DOI: 10.3233/JAE-190127

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-14, 2020

Authors: Zhang, Jin | Zhang, Qiuju

Article Type: Research Article

Abstract: The purpose of this paper is to optimize the PM arc ratio of consequent pole permanent magnet vernier machine (CP_PMVM). The operation principle of the CP_PMVM is discussed. An optimization parameter K 𝛼 related to the PM arc ratio is derived. For the CP_PMVM, the amplitudes of the 4th and 14th order harmonics of the air-gap flux density, the amplitude of the back electromotive force (back-EMF) and the average torque all have positive correlations with K 𝛼 . The optimal PM arc ratio is 0.64. The three phase inductances are approximately constants, and the d -axis inductance is equal …to the q -axis inductance. The PM flux linkages are sinusoidal. The no-load back-EMF waveform of the measured phase is nearly sinusoidal. The gear ratio of the CP_PMVM evaluated from the back-EMF is close to the design value. Furthermore, a controller according to the mathematical model is designed. The CP_PMVM vector control with a sliding-mode (SM) speed controller exhibits a smooth starting, and has an anti-jamming capability. Show more

Keywords: Consequent pole (CP) rotor, permanent magnet vernier machines (PMVM), sliding mode (SM), vector control

DOI: 10.3233/JAE-190061

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-16, 2020

Authors: Hasan, Alfaisal A. | Mekheimer, Khaled S. | Tantawy, Bassem E.

Article Type: Research Article

Abstract: The present work studies magnetohydrodynamic stability with streaming resistive triple superposed fluid layers. This system is influenced by an oblique magnetic field. The solution of motion equations by using the method of perturbation analysis under the boundary conditions which leads to deriving the dispersion relationship describing the behaviour of the perturbed and unperturbed system. The effect of different parameters on the stability and the instability of this system was studied. Regions of stability and instability are identified by drawning the curves to illustrate the regions of stability and instability behaviour. It is found that the magnetic field permeability coefficient, the …intensity of the magnetic field values, the increase of the fluids density values and the streaming velocity have destabilizing influences on the considered system. The presence of an oblique magnetic field plays a stabilizing role and can be used to retard the destabilizing influence. Show more

Keywords: Self-gravitating, resistive, superposed fluids, streaming, oblique magnetic fields

DOI: 10.3233/JAE-190110

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-11, 2020

Authors: Li, Peng | Jiang, Jiafu | Liu, Sheng | Fu, Peng | Huang, Yiyun | Hui, Xie | Qiang, Liu | Hongyan, Zuo

Article Type: Research Article

Abstract: As an important electrical power distribution system of ITER (International Thermonuclear Experimental Reactor) device, PPEN (Pulsed Power Electrical Network) feeds the pulsed loads for the superconducting coils and the heating and current driving systems. The PPEN transforms 400 kV power grid to 66 kV and 22 kV distribution voltage levels by 3 main step-down transformers. In this paper, the power loss of PPEN transformer is analyzed and calculated. The 2D PPEN transformer model is built. The temperature rise of PPEN transformer is calculated by ANSYS software. To validate the feasibility and correctness of the proposed method, the temperature rise test of PPEN transformer …is carried out, then the related results are compared with the test data. Show more

Keywords: ITER, PPEN, temperature rise, ANSYS, short-circuit method

DOI: 10.3233/JAE-190105

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2019

Authors: Bai, Peigen | Shi, Pengpeng | Zhao, Yingsong | Chen, Hong-En | Xie, Shejuan | Chen, Zhenmao

Article Type: Research Article

Abstract: As one typical material of nuclear power plant structure, austenitic stainless steel (SS) is often accompanied by residual stress and plastic deformation during their manufacture and application, which may affect the structure service safety. In this paper, the effects of the composite state of residual stress and plastic deformation on the pulsed eddy current testing (PECT) signals of SS are studied theoretically and experimentally. By considering the electromagnetic properties in the composite state, the PECT theory is established for the 304 SS in the composite state. The numerical simulation is completed using the reduced vector potential method and the verification …experiment is also carried out. The comparison between simulation and experimental results shows that the peak value of the PECT signal increases with the increase of plastic deformation or residual stress. This means that if the residual stress is not considered in the composite state, the effectiveness of the PECT method for evaluating plastic deformation may be seriously affected. Show more

Keywords: 304 austenitic stainless steel, composite state, plastic deformation, residual stress, pulsed eddy current testing

DOI: 10.3233/JAE-190124

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-12, 2019

Authors: Chang, Jiujian | Fan, Yanen | Zhu, Bo | Luo, Liang | Wu, Jinglai | Pan, Yishan | Kang, Peng

Article Type: Research Article

Abstract: This paper takes the demand of high power density motor for new energy vehicles as the application background. In order to solve the problem of low power density of radial flux motor, a novel direct cooling yokeless and segmented armature axial flux machine (YASA) is proposed. The thermal-fluid multi-physical coupling field of YASA motor has been studied by combining numerical analysis and computational fluid dynamics (CFD). On this basis, the internal relationship among the output power, flow resistance and structural parameters of the cooling system has been studied, and then the parameters of cooling system has been multi-objectives optimized. On …the premise of meeting the pressure loss of the cooling system, the heat transfer efficiency has been improved, and then the output power of the motor has been increased. Show more

Keywords: YASA, cooling system, power density, CFD, pressure loss

DOI: 10.3233/JAE-190085

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

Authors: Ding, Li | Zhang, Jiasheng | Lin, Aiguo | Ge, Yulei

Article Type: Research Article

Abstract: In actual operation, the skin effect electric heat tracing system is powered by the inverter circuit, and the higher harmonic components are inevitably introduced. There is not much research on the influence of harmonic current on the electric heat tracing load loss. In this paper, the harmonic distribution under PWM driving mode is analyzed, and the load loss of the electric heat tracing body under harmonic current is derived. The co-simulation method of PWM inverter circuit and skin electric heat tracing body coupling is proposed. The simulation results of current and loss of co-simulation method and sine wave driving method …are compared. The results show that the parameters of PWM driving mode increase to different degrees, which proves the correctness of the joint simulation method. At the same time, the influence of the output characteristics and modulation parameters of the PWM inverter circuit on the load loss of the electric heat tracing body is analyzed, which provides a theoretical basis for the determination of the parameters of the inverter circuit. In addition, combined with multi-physics coupling analysis, this paper obtains more accurate temperature distribution results of the electric heat tracing system without scaling the size of the electric heat tracing ontology. Not only can we intuitively understand the material selection and hot spot configuration of the electric heat tracing components, but also further understand the influence of current harmonics on the load loss in actual operation, so as to better realize the efficient heat tracing of the skin electric heat tracing system. Show more

Keywords: Electric heat tracing system, harmonic analysis, loss calculation, co-simulation, multi-physics coupling analysis

DOI: 10.3233/JAE-190106

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-16, 2019

Authors: Li, Ke | Ling, Feng | Sun, Xiaodong | Cai, Yingfeng | Zhao, Dean | Yang, Zebin

Article Type: Research Article

Abstract: The traditional displacement sensors used in the bearingless induction motors (BIM) have many disadvantages, such as high cost, poor temperature stability, low conversion efficiency and complex motor operation. To improve these disadvantages, the detailed study on the novel displacement sensorless control based on the model reference adaptive system (MRAS) is presented in this paper. Firstly, the principle of radial suspension force generation and the mathematical model of the BIM are introduced. Secondly, the basic structure of the proposed MRAS is constructed and the stability is verified by the Popov’s integral inequality. Thirdly, to improve the control accuracy and dynamic characteristics …of sensorless vector control system, a method of directly controlling rotor eccentric displacement by using suspension force compensation is proposed. Finally, the feasibility and accuracy of the proposed method have been verified by the simulation and experimental results. According to the results obtained, the radial displacement of the rotor can be accurately estimated, and the rotor displacement sensorless control of the BIM based on MRAS is achieved. Show more

Keywords: Bearingless induction motor, model reference adaptive system, rotor displacement sensorless control, direct suspension force control

DOI: 10.3233/JAE-190118

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-19, 2019

Authors: Yao, Wang | Hai Tao, Yu | Rong, Guo | Dong Yang, Li | Ningjun, Feng | Zheng, Xu

Article Type: Research Article

Abstract: An extended state observer (ESO) based fuzzy adaptive sliding mode control (FASMC) for permanent magnet synchronous motor (PMSM) drive system is proposed in this paper. In order to improve the disturbance rejection property, a dynamic disturbance compensation method is developed based on extended state observer. A fuzzy adaptive sliding mode control method with a novel sliding mode reaching law is presented to enhance the tracking performance. Then, the proposed method called FASMC-ESO, is applied to regulate the speed of PMSM. The global asymptotic stability analysis of the system is proved by Lyapunov functions. Comparative simulation and experiment results verify the …effectiveness of the proposed method. Show more

Keywords: Disturbance observer (DO), permanent magnet synchronous motor (PMSM), fuzzy adaptive (FA), sliding mode control (SMC), extended state observer (ESO)

DOI: 10.3233/JAE-190098

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-17, 2019

Authors: Zuki, Nor Aishah Md | Othman, Raja Nor Firdaus Kashfi Raja | Ahmad, Suhairi Rizuan Che | Shukor, Fairul Azhar Abdul

Article Type: Research Article

Abstract: This paper discusses the constants in various types Double Stator Permanent Magnet Brushless DC Motor (DSPM BLDC). Hybrid or electrical vehicles requires fast response motor that are capable of reacting as soon as possible. Thus, the motor should have a faster time response with lower electrical time constant, T e and mechanical time constant, T m . However, there are few literatures that reported the time response for a double stator topology. The time response relates to various constant parameters of the motor. It is known that double stator has high torque density which can be implemented …for other applications in the future. For this research, various DSPM BLDC motors had been redeveloped. Finite Element Method (FEM) was used to simulate the characteristics of DSPM BLDC motor that considered the presence of the analytically calculated T e and T m . The results show that the Double Stator Slotted Rotor Permanent Magnet Brushless DC Motor (DSPM-SR) had good performance such as highest back emf, torque and good time response. A prototype of DSPM-SR had been manufactured and measured. The percentage differences between Analytical-FEM and Analytical-Mea for T e and T m were 4.2% and 9.1%, respectively. As a conclusion, this paper reveals the constants that could affect the performance of double stator topology. Show more

Keywords: Double stator, electrical time constant, mechanical time constant

DOI: 10.3233/JAE-190126

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-17, 2019

Authors: Iwamoto, Yuhiro | Nakasumi, Hayaki | Ido, Yasushi | Yamaguchi, Hiroshi

Article Type: Research Article

Abstract: Mn-Zn ferrite-based magnetic fluid is temperature-sensitive. Because of the low Curie temperature of Mn-Zn ferrite particles, magnetization is dramatically attenuated as the temperature rises. This temperature-dependent magnetization can be used to transport heat by magnetically driving a fluid via the application of a non-uniform magnetic field and heat. A potential application of this scheme is long-distance heat transport without the use of mechanical pumps. In the present work, a miniaturized magnetically-driven heat transport device with an inner diameter of 𝜙1.54 mm and a flow path length of 1,500 to 6,000 mm was fabricated. The influence of flow path length on the flow …rate induced by the magnetic body force was investigated experimentally and theoretically. Although the flow rate decreased with increasing flow path length due to friction loss, the driving pressure increased with rising heater temperature because of the temperature-dependent magnetization. The influence of flow path length on the driving pressure is relatively insignificant. An increase in the flow path length leads to effects that both attenuate and enhance the driving pressure. Substantial long-distance (6,000 mm) heat transport was realized by applying a non-uniform magnetic field and heat. Show more

Keywords: Magnetic nanofluid, heat transfer, magnetic fluid, temperature-dependent magnetization, energy conversion

DOI: 10.3233/JAE-190033

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-14, 2019

Authors: Yan, Dong | Guo, Liyan | Shi, Tingna | Wang, Huimin | Yan, Yan | Xia, Changliang

Article Type: Research Article

Abstract: The split ratio is one of the most important design parameters of the machines and has a significant effect on the electromagnetic performance. Using the split ratio, this paper presents a performance analysis method for permanent magnet (PM)-assisted reluctance machine is presented. An accurate analytical model, which considers the saturation of outer iron ribs and the asymmetric saturation of rotor islands, is firstly proposed. In order to reduce the numbers of the adjustable structural parameters during the initial design process and ensure the independence among the parameters, a geometric structure corresponding to the split ratio is then established. The effectiveness …of the proposed analytical model based on the split ratio is verified by FEM, and applied to analyze the electromagnetic performance for the three-flux-barrier PM-assisted reluctance machines. On the basis of the analysis results, the design scheme corresponding to the optimal split ratio, which makes the machine obtain a higher efficiency and guarantees the PMs without irreversible demagnetization, is determined rapidly. Show more

Keywords: Permanent magnet (PM)-assisted reluctance machine, the gradient flux barrier, split ratio, analytical model

DOI: 10.3233/JAE-190104

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-25, 2019

Authors: Yan, Xinxiao | Li, Yongjian | Cheng, Zhiguang | Zhang, Changgeng

Article Type: Research Article

Abstract: A 3-D coupled magneto-fluid-thermal model is established for temperature rise prediction in a ventilated dry-type transformer rated at 2500 kVA. In order to accurately estimate electromagnetic losses, a three-dimensional (3-D) transient finite element method considering the effect of eddy-current losses on the foil type windings is proposed. Besides, two orthogonal B -P loss curves are adopted to model the anisotropy of grain-oriented (GO) silicon steel. The non-uniform power losses of winding and core are mapped into the thermal field as heat sources. Moreover, the transformer structures such as the narrow struts, insulation barrier and clamps are considered to improve the …computational accuracy of air velocity and temperature distribution. At last, the test of temperature rise has been carried out to verify the proposed model. Show more

Keywords: Dry-type transformer, eddy currents, power losses, magnetic measurements

DOI: 10.3233/JAE-190054

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

Authors: Zhao, Jianhui | Yue, Pengfei | Wei, Kebiao

Article Type: Research Article

Abstract: A high-speed solenoid valve (HSV) with high dynamic responses is a key component of the common rail injector, where it provides accurate and flexible control of the injection. In this study, finite element methods were used to investigate the eddy current inside an HSV. The results demonstrated that the appearance and change in the eddy current were related to the driving current, and significantly influenced the HSV dynamics, particularly the opening response. By considering the eddy current effect, the calculations were seen to match the experimental data effectively during the opening response, but did not match them strongly during the …closing response. During the HSV opening process, the eddy current at the surface of the magnetic materials impeded the magnetization; during the closing stage, it prevented the magnetic flux inside the magnetic material from spreading out and delayed demagnetization. An eddy current was proven to always block the magnetic field change and worsen the HSV dynamic response. Slotting on the yoke can significantly reduce the open response time, while hardly influence the close response. It was deemed necessary to optimize the HSV structure to weaken the eddy current effect on the opening and closing response. Show more

Keywords: eddy current effect, dynamic response, high-speed solenoid valve, common rail injection system, diesel engine

DOI: 10.3233/JAE-190047

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2019

Authors: Guo, Yujing | Jin, Ping | Ding, Yan | Zhao, Kai | Issoufou, Abdoul Zaid

Article Type: Research Article

Abstract: In this paper, one kind of U-shape permanent magnet embedded salient pole wind generator is proposed. The permanent magnet is divided into three sections to form a U-shaped structure and inserted into the salient pole in the generator. The size of the PM near the side frame is small, therefore, there is sufficient PM location modification space in the salient pole. Some flux-barriers are set in the upper core of the salient pole, which can reduce the q -axis inductance, and ultimately increases the generator maximum output power. To evaluate the generator’s overall performance, some other important electromagnetic parameters such …as the air-gap flux density, the output voltage, the cogging torque, the output power, and the demagnetization performance are all calculated and analyzed base on finite element method (FEM). All the above parameters are compared with that of one V-shape permanent magnet embedded salient pole wind generator. The analysis results show that, with the same volume of permanent magnet, the proposed U-shape permanent magnet embedded salient pole wind generator has higher power density than the V-shape permanent magnet embedded salient pole wind generator. Show more

Keywords: Electromagnetic parameter analysis, reluctance power, salient pole, wind generator

DOI: 10.3233/JAE-190026

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

Authors: Sun, Hongyu | Wang, Shen | Huang, Songling | Wang, Qing | Zhao, Wei

Article Type: Research Article

Abstract: Electromagnetic ultrasonic testing, based on the propagation characteristics of the ultrasonic wave in the medium, is an effective technique for defect detection. The structural of the electromagnetic acoustic transducer (EMAT) determines the detection effect, which should be reasonably designed. We propose an improved unilateral point-focusing EMAT structure with curved coils in this manuscript. The 3D model of the designed EMAT is numerically simulated utilizing the finite element method, and the bilateral point-focusing EMAT is also studied for comparison. The simulation results of the magnetic field intensity and the distributions of the displacement are shown in the manuscript, which prove the …effectiveness of the improved unilateral point-focusing EMAT. Five impact parameters such as aperture angle, focal position, excitation current, lift-off distance, and coil winding number are investigated in detail. We verify the calculation results of the aperture angle and excitation current by the experiments. The conclusion shows that the focusing intensity of the improved unilateral point-focusing EMAT is relatively higher, and other factors also have a significant effect on the focal intensity. Show more

Keywords: Point focusing, electromagnetic acoustic transducer (EMAT), unilateral, bilateral, numerical simulation

DOI: 10.3233/JAE-190071

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-18, 2019

Authors: Yang, Yiyi | Su, Sanqing | Wang, Wei | Ma, Xiaoping | Hu, Jingyu

Article Type: Research Article

Abstract: Metal magnetic memory (MMM) testing method has been proved to be a valid approach to monitor early damage and predict fatigue life, but there is no systematic description and comparison about the characteristics of MMM signals for welding and non-welding specimens with different materials under tension-compression fatigue. Thus, the fatigue tests for Q345B and Q345qC welding and non-welding specimens were carried out and the MMM testing was done synchronously. Then, based on the normal components of MMM signals, H p (y ), and its variations, ΔH p (y ), the slope of ΔH p (y ) fitting …curves, K C , and the average of ΔH p (y ) signals on the whole testing line, ΔH p (y )ave , were extracted as the characteristic parameters for Q345B and Q345qC non-welding specimens, respectively. Additionally, the gradient of “peak–vale” on H p (y ) signals curves, k , and the average of H p (y ) signals in the scope of welding zone, H p (y )ave , were extracted as the characteristic parameters for Q345B and Q345qC welding specimens, respectively. Some conclusions can be drawn by comparison: the variation laws of H p (y ) signals with cyclic loads are related to the material. The characteristic parameters for welding and non-welding specimens with the same material have a certain similarity. Then, the failure of non-welding steel can be warned early by K C or ΔH p (y )ave when the fatigue life has 20% left, but the damage degree of welding specimen should begin to be valued highly once the k or H p (y )ave is decreasing. Finally, the fatigue life of welding and non-welding specimens with different materials can be evaluated effectively by using corresponding magnetic characteristic parameters. Show more

Keywords: Metal magnetic memory (MMM) testing, fatigue life, magnetic characteristic parameter, Q345B and Q345qC steel, weldments

DOI: 10.3233/JAE-190064

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-25, 2019

Authors: Park, Eui-Jong | Jung, Sang-Yong | Kim, Yong-Jae

Article Type: Research Article

Abstract: The magnetic gears which can replace the mechanical gear system are actively studied recently. Improving the power density is growing importance because the characteristics that as gear ratio grows so power density decreases were observed. This paper analyzes the various characteristics (power density, efficiency, torque ripple, loss, and so on) according to the gear ratio in detail, and proposes a concept that high gear ratio by combining two low gear ratio. A target gear ratio is 10 to 1 and application is 1 kW wind turbine. To obtain the optimal combination, 30 gear ratios were considered, and initial design process was …shown about this concept to propose the direction of improving the power density. All models were analyzed with 2D-FEM by numerical analysis. Show more

Keywords: Finite element analysis, magnetic gears, power density, high gear ratio

DOI: 10.3233/JAE-190097

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2019

Authors: Toghraie, Davood

Article Type: Research Article

Abstract: Optimization of the cooling processes by fluids in many industries such as power generation, transportation, machining, and electronics is very important. Heat transfer equipment to achieve higher efficiency, need to downsizing of the equipment, and increase the heat transfer rate per unit of surface. The aim of this paper is to investigate the effect of MHD mixed convection flow of Cu-water nanofluid in a trapezoidal lid-driven cavity with different tilt angles in a range of 0° to 60°. The cavity consists of the non-uniformly heated bottom wall, insulated top wall, and isothermal sidewalls. The governing equations of the flow by …using the finite volume method and the SIMPLE algorithm have been numerically solved. The studies for the wide range of Richardson number (Ri) from 0.01 to 10, volume fraction of nanoparticles from 0.1% to 4% and Hartman number (Ha) from 0 to 40 in the steady-state have been done. Result in the form of streamline, vorticity and temperature contours for three geometry, local Nusselt number graphs for non-uniformly heated bottom surface and velocity profile on the vertical centerline of the cavity in different geometry have been investigated. The results show that the average Nusselt number on the non-uniformly heated bottom wall is dependent on dimensionless parameters and tilt angles. Also, applying a magnetic field, reduce the velocity profile changes, and using nanoparticles will cause increasing the Nusselt number. Show more

Keywords: Mixed convection, magneto-hydrodynamic, trapezoidal cavity, non-uniformly heated surface

DOI: 10.3233/JAE-190123

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-28, 2019

Authors: de Souza Lima, Diorge | Mahmud, Lucas S. | de Sousa, Antonio R. M. | da S. Fonseca, Wellington | Bezerra, Ubiratan Holanda | Bezerra, Fábio Vinícius V.

Article Type: Research Article

Abstract: Sympathetic inrush current phenomenon occurs when a transformer is switched on in a power network containing other transformers that are already energized. This interaction significantly changes duration and magnitude of transient magnetizing currents in the transformers involved and may lead to misoperation of these equipment. Therefore, in this paper it is presented the results of electromagnetic analysis due to sympathetic inrush and inrush current phenomenon among single-phase 50 MVA transformers in a power substation in the northern region of Brazil. For this purpose, the nine single-phase transformers installed at SE Guamá forming three three-phase banks, were modeled in the ATP software …to obtain the energization behavior. In this paper the electromagnetic analyzes are performed in steady state, so only the first peak is used. In this way, results of the electromagnetic behavior of transformers are presented and compared sympathetic inrush with inrush current. Show more

Keywords: Sympathetic inrush, transformers bank, MEF, ATP software

DOI: 10.3233/JAE-190041

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-16, 2019

Authors: Ahn, Dahoon | Kim, Hyunchang | Choi, Kyungwho | Choi, Young-Man | Lim, Jae-Yong

Article Type: Research Article

Abstract: Magnetic levitation is state-of-the-art technology to realize 6 degree of freedom motion stages. The major weakness of magnetic levitation technology is the small force of the actuators, since electromagnetic actuators usually have small force compared to other actuators. Moreover, they always have to be turned on in order to compensate for the weight of the stage. In this paper, voice coil motors, a kind of electromagnetic actuator, are designed for a magnetic levitation stage. Two different types of voice coil motors are mathematically modeled, analyzed and optimized to obtain high force. According to the optimized final designs, the voice coil …motors are manufactured and their performances are evaluated. The optimal design results are compared with the finite element simulations and the test results of the manufactured products. Both types of voice coil motors show high force. The results are quantified and compared. Through the design process and the evaluation of the voice coil motors, a practical design guideline for a voice coil motor is suggested. Show more

Keywords: Voice coil motor, optimal design, aspect ratio, force capacity

DOI: 10.3233/JAE-190029

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-24, 2019

Authors: Ju, Lufeng | Tao, Wenqiang | Wang, Qunjing | Li, Guoli | Zhou, Rui | Qiao, Yuanzhong

Article Type: Research Article

Abstract: A novel three-degree-of-freedom (3-DOF) spherical motor based on the principle of minimum magnetic reluctance is proposed in this paper. This paper firstly introduces the structure of the reluctance spherical motor and explains the principle of 3-DOF motion of the motor in detail. Then, an analytical model for reversible torque-angle characteristics is established to accurately describe a complex nonlinear system of the spherical motor model by using piecewise function nonlinear fitting method. Finally, the simulation results of torque-angle characteristics based on the nonlinear model are compared with those of the 3D finite element method (FEM), which verifies the feasibility of the …nonlinear modeling. Show more

Keywords: Spherical motor, 3-DOF, nonlinear modeling, torque-angle characteristics, FEM

DOI: 10.3233/JAE-190072

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-17, 2019

Authors: Audiffred, D.B.S. | Possamai, T.S. | Travassos, X.L. | Ida, N.

Article Type: Research Article

Abstract: Composite materials have diverse engineering applications including the automotive, energy and aerospace industries. In manufacturing aircraft structures, the material is expected to endure atmospheric discharges. The present paper aims to model some of the effects of lightning strikes on a composite materials modeled through numerical simulation. The simulation is based on the finite-difference time-domain method which allows analysis the electromagnetic and thermal effects related to the problem. Aerospace standards are taken into account for modeling a lightning strike on a composite plate. The thermal distribution is evaluated based on results obtained from an electromagnetic simulation of the lightning strike effect. …Since multiphysics problems are complex, the hypotheses adopted to obtain the results are also discussed. Results show the current density distribution on a carbon fiber reinforced plastic plate varying with the anisotropy characteristics of the material. From the thermal simulation it is shown that the lightning strike can cause a rise in the composite temperature over 900 °C with only 1 μs of interaction with the material. Show more

Keywords: Lightning strike, composites, numerical modeling, multiphysics modeling

DOI: 10.3233/JAE-190045

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-19, 2019

Authors: Su, Sanqing | Wei, Luxi | Wang, Wei | Yang, Yiyi | Ma, Xiaoping | Zuo, Fuliang

Article Type: Research Article

Abstract: Metal magnetic memory testing (MMMT) is a nondestructive testing technique that can detect early damage of component. In order to distinguish the effect of normal stress and shear stress on magnetic field, the flexural loading testing of inclined steel box girder with corrugated web is carried out by four-point bending pattern, and the normal component of the magnetic field at different position of the beam under different load level are collected. It is found that the law of normal component of the magnetic field changing with load is similar under different stress states, but the amplitude is quite different. The …stress in Jiles–Atherton model can be replaced by equivalent stress when calculating the magnetic field under shear stress. Show more

Keywords: Metal magnetic memory testing (MMMT), bridge steel Q345qC, four-point bending, shear stress, equivalent stress

DOI: 10.3233/JAE-190075

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-16, 2019

Authors: Yao, Xing-Yan | Pecht, Michael

Article Type: Research Article

Abstract: Magnetorheological (MR) damper is a smart device which the damping force can be adjusted according to the working operations in a short time. Metal foam MR damper is a new type of MR dampers in which uses the metal foam to store and release the MR fluids. The dynamic response time of the metal foam MR damper is quite different due to the added metal foam especially for the dynamic response time model. This paper proposed a dynamic response time model for the metal foam MR damper based on the demonstration of the working mechanisms and the factors about the …response behaviors. Show more

Keywords: Magnetorheological (MR) fluid, MR damper, metal foam, dynamic response time model

DOI: 10.3233/JAE-190063

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2019

Authors: He, Yunfeng | Zhan, Jiawen | Lu, Qinfen

Article Type: Research Article

Abstract: In order to fast calculate the thrust force and normal force of linear induction motor (LIM) for low-speed maglev train under overall conditions including traction and braking, this paper proposes an improved equivalent circuit (EC) method. Firstly, the improved equivalent circuit model is proposed based on the traditional one by adopting a precision correction factor, which can accurately consider the transverse edge effect of cap-shape secondary conducting sheet. Moreover, the permeability of back-iron and magnetic inductance are amended considering the saturation effect. The corresponding calculation procedure is given out. Then, the precise correction factor is investigated based on 2D finite …element (FE) model. By comparison with the traditional Russell and Norsworthy correction factor (RNF), the precision correction factor is proved to be more suitable to LIM with wide-range slip frequency. Finally, the thrust force and normal force of LIM with different slip frequency are predicted under braking and traction conditions by improved EC method. The predicted results and the proposed method are validated by 3D FE method and experiment results. Show more

Keywords: Braking condition, equivalent circuit (EC) method, linear induction motor (LIM), low-speed Maglev train, normal force, slip frequency, transverse edge effect

DOI: 10.3233/JAE-190053

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

Authors: Hao, Yang | Heng, Liu | Fan, Yang | Zhenwei, Ji | Bing, Gao | Min, Gong | Boda, Zhou | Chenzhi, Zhu

Article Type: Research Article

Abstract: The special working condition of shore power cable is more likely to form a crack air gap in insulating medium, which will cause gap discharge. The continuous gap discharge will cause local temperature rising and stress concentrating, which will lead to cable insulation deterioration. The electro-thermal-stress coupling method, in this paper, is used to establish the finite element model of the shore power cable. The electric, temperature and stress field distribution for the shore power cable with a crack air gap in the insulating medium is also studied, and the correctness of temperature and stress field distribution is verified by …experiments. In addition, this paper investigated the variation law of the ampacity for shore power cable under different discharge energy. The results show that the maximum electric field is equal to the electric field intensity (36.1 kV/cm) at the inner edge of the insulating medium when the gap length d = 2 mm and that the temperature and stress of the cable are quadratic with load current, linear with the gap discharge energy. The research results of this paper have an engineering significance for monitoring shore power cables. Show more

Keywords: Shore power cable, multi-physics field, discharge energy, ampacity

DOI: 10.3233/JAE-190088

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-15, 2019

Authors: Wu, Jiamin | He, Yucheng | Shen, Sheng | Guo, Pan | Huang, Xin | Xu, Zheng

Article Type: Research Article

Abstract: Traditional nuclear magnetic instruments are not convenient for measurement in situ due to the closed magnet structure and heavy weight. It is crucial to improve tree planting by exactly detecting moisture parameters of living trees. To investigate this problem, an open and portable magnetic resonance sensor was proposed. In this work, we introduced unilateral magnetic resonance sensor which can achieve onsite nondestructive measurement of large-volume samples due to its open structure. To fit the shape of living trees, the region of interest was set in an arc region. A magnet structure was optimized by ANSYS software. Because the magnet has …a constant natural gradient along radial direction, we need gradient fields in the other two directions (Z and Y). Z/Y gradient coils for unilateral magnetic resonance sensor are studied based on the Fourier series method. Current density in gradient coils is assumed as Fourier series composed of trigonometric functions. We introduced stream function to establish relationship between the current density and the winding structure, then constructed an optimization model by combining power dissipation with the deviation between calculated field and target field. The coils are manufactured using a flexible printed circuit board and measured by gauss meter. The measurement and simulation results are consistent. Measurement results of the gradient coils showed that the magnetic fields have good linearity which is helpful to realize 3D measurement in the upcoming work. Show more

Keywords: Unilateral magnetic resonance, Fourier series method, gradient coil design

DOI: 10.3233/JAE-190076

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

Authors: Liu, Bingcheng | Liu, Ning | Wang, Shaoyi | Jia, Wenguang

Article Type: Research Article

Abstract: Magnetic induction intensity and current are crucial factors to determine the effect of electromagnetic anti-fouling technology (EAFT). For getting the current value in the coil which was tightly wrapped around the PVC pipe, the inductance and equivalent resistance of the coil was measured by LCR meter, and the current in the circuit of the anti-fouling system was obtained by Ohm’s law. The magnetic induction intensity in the solenoid centre can be calculated by Faraday’s law. The purpose of the experiment was to find the optimal output parameters of EAFT and explored the anti-fouling effect. Therefore, we established an experimental platform …to optimize the output parameters and explore the effect of different output frequency on solution conductivity and particle diameter. Through experiments, it’s found that current in the coil was reduced with increasing frequency, the number of turns and the diameter. As the frequency and diameter increase, the magnetic induction intensity reduced, and the turns basically no impact on the magnetic induction intensity. The hardness solution of 10 mol ⋅ m−3 (as CaCO3 ) is treated by four different frequencies electromagnetic field shows that the lower the frequency, the greater decrease in conductivity and the greater increase in particle size, that phenomenon verifying that the higher current and stronger magnetic field intensity has a better anti-fouling effect. Show more

Keywords: Electromagnetic anti-fouling technology, current, magnetic induction, conductivity, particle diameter

DOI: 10.3233/JAE-190055

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