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

Authors: Gong, Qi | Zhang, Weiwei | Su, Yufeng | Zhang, Kun

Article Type: Research Article

Abstract: In this paper, a diamagnetic-airflow hybrid levitation structure is reported, with a floating magnet rotor stably levitated above a diamagnetic disc just using a lifting magnet and airflow. Compared with the typical diamagnetically stabilized structure, the rotation speed of the rotor is increased from 9570 rpm to 16666 rpm, and the levitation gap is increased from 0.3 mm to 0.7 mm when the airflow rate exceeds 2198 sccm under standard temperature and pressure (STP). At the same time, the rotor can be stably levitated at any height from 0.2 mm to 0.8 mm by adjusting the vertical position of the nozzles. With the hybrid levitation structure, it’s …possible to overcome the structural limitation of typical diamagnetically stabilized levitation structure and enhance the working performance of the rotor. This levitation structure is expected to be applied to sensing, energy harvesting and air bearing under actuation of airflow. Show more

Keywords: Diamagnetic, airflow, stabilized levitation, simulation, energy harvesting

DOI: 10.3233/JAE-190081

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

Authors: Mingliang, Zheng

Article Type: Research Article

Abstract: In this paper, the Lie symmetry theory of singular mechanico-electrical coupling systems is studied in phase space. Firstly, the Hamilton canonical equation of singular mechanico-electrical coupling systems is established through energy; Secondly, considering the inherent constraints brought by singularity, the determining equations, definitions, structural equations and conserved quantities of Lie symmetry are all given; Finally, an application example is given. It is shown that if the structural equation of Lie symmetry is just right the criterion equation for Noether symmetry, then the Lie symmetry can lead to the conserved quantity of Noether type; if the structural equation of Lie symmetry …does not involve the Hamiltonian function, the conserved quantity of non-Noether type can be obtained only through finding the invariant of symmetric group. Show more

Keywords: Singular mechanico-electrical coupling systems, Lie symmetries, structural equations, conserved quantities

DOI: 10.3233/JAE-190059

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2019

Authors: Shi, Yan | Lin, Cong | Lu, Bin

Article Type: Research Article

Abstract: Electromagnetic linear actuator (EMLA) is an alternative of the conventional damper in vehicle suspensions and harvests suspensions vibration energy which is wasted generally. Due to large variations of its Back Electromotive Force (Back-EMF), it will thus be interest to investigate how to recycle the electricity efficiently. In this paper, to improve the recycling efficiency of the EMLA, a feedback energy circuit featured with combination of parallel switchover supercapacitors technology and a boost-buck DC-DC converter is proposed on the basis of the generating characteristics of a newly designed EMLA. By modeling the feedback energy circuit, its dynamic characteristics are simulated and …its efficiency is investigated. The results of simulations and experiments show that the feedback energy circuit can achieve a wide range of energy recovery regardless of large variations of Back-EMF induced by the EMLA. Simultaneously, by keeping the boost-buck ratio less than 3, the efficiency of energy recovery is high, in some cases could reach 94%. Show more

Keywords: Energy harvesting, electromagnetic linear actuator, active suspensions, feedback energy circuit

DOI: 10.3233/JAE-180135

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

Authors: Liu, Yafeng | Wang, Xinjie | Wang, Jiong | Chen, Hejuan

Article Type: Research Article

Abstract: The lanthanum-doped lead zirconate titannate (PLZT) ceramic has shown its potential applications as light-controlled micro actuators activated by ultraviolet light for the photovoltaic effect in the field of micro-driven. Aiming to the slow response of photostriction of PLZT ceramic, the primary purpose of this article is to propose a light-controlled actuator with the novel opto-electrostatic hybrid driving based on PLZT ceramic. The mathematical model of the proposed light-controlled actuator is established on basis of the anomalous photovoltaic effect model of PLZT ceramic. The actuation characteristics of the micro actuator are investigated based on the established mathematical model and the experiments …of the photovoltage of PLZT ceramic. Furthermore, the actuation curves of the micro actuator driven by opto-electrostatic hybrid driving based on PLZT ceramic are acquired to verify the rationality and feasibility of the light-controlled micro actuator design. So according to the analysis and experimental results, the light-controlled actuator driven by the novel opto-electrostatic hybrid driving based on PLZT can conduct the effectively and precisely displacement control with fast response speed. In addition, the driving method based on the novel opto-electrostatic hybrid driving has advantages of non-contact control, remote control and no electromagnetic interference, etc. Show more

Keywords: PLZT, micro actuator, opto-electrostatic hybrid driving, light-controlled

DOI: 10.3233/JAE-190035

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

Authors: Li, Zhao | Yan, Li | Qu, Boyang | Fu, Kai

Article Type: Research Article

Abstract: In this paper, an analytical model is proposed to predict the magnetic field and torque characteristics of flux-concentration cage-type eddy-current couplings with slotted conductor rotor topology. Due to the presence of discontinuous boundary conditions in permanent magnet rotor domain and conductor rotor domain, the accurate sub-domain method is employed in polar coordinates. The permanent magnet domain and the conductor domain are divided into different sub-domain according to the number of poles and slots. The magnetic vector potential in each domain is obtained by solving the field equation based on the separated variable method. Then the magnetic field distributions and output …torque are computed. By using the nonlinear 2D and 3D finite element analysis, the validity of such model is proved, and the cause of deviation is discussed. In the end, the proposed formula is used for a design optimization using particle swarm optimization algorithm. Show more

Keywords: Eddy-current couplings, sub-domain method, finite-element method, design optimization

DOI: 10.3233/JAE-190056

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

Authors: Zhang, Yuyang | Leng, Yonggang

Article Type: Research Article

Abstract: Magnets are widely used in many fields, both industry and our daily life, because of their unique properties such as non-contact interactions and electricity generation. However, behaviors of permanent magnets seem to deviate from our basic understanding that opposite poles attract and like poles repel. We have recently discovered an interesting phenomenon in pairs of permanent magnets with large different sizes where the like poles do not seem to repel and the unlike poles do not seem to attract with each other, due to a localized area with reversed pole existing in the large permanent magnet. In this paper, we …first experimentally confirm the existence of this particular phenomenon by studying interactions of several groups of permanent magnets with different sizes, then we introduce the property of the irreversible movements of load line and working point of permanent magnet to figure out this transition process from repulsion to attraction between a pair of permanent magnets with large different sizes. A reasonable explanation is finally given. In the end, we suggest a few applications for this special phenomenon. Show more

Keywords: Magnetic force calculation, load line, demagnetizing field, working point

DOI: 10.3233/JAE-190057

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

Authors: Wu, Jie | Hu, Hong | Liang, Jian

Article Type: Research Article

Abstract: This paper investigates the magnetic circuit model of a multi-pole multi-layer magnetorheological (MR) brake. Firstly, a simple introduction to the structure is given. This MR brake has a unique structure design with several MR fluid working gaps set between two-layer coils. Then, magnetic circuit model is conducted to theoretically approximate the effects of the design parameters on the magnetic field strength within the MR fluids. According to the magnetic circuit analysis, a parametric study is performed to optimize the critical design parameters of the magnetic circuit of the designed brake. Finally, the magnetic circuit model is validated based on the …optimized structure and simulation. Simulation results indicate that the magnetic circuit model is feasible to estimate the magnetic field strength in the working gaps, and it can be used to guide the parameters optimization and structure design. Show more

Keywords: Magnetorheological (MR) brake, magnetic circuit, modeling, finite element analysis, optimization

DOI: 10.3233/JAE-190025

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

Authors: Liu, Qing | Wang, Li | Zhang, Shiping | Wang, Xinjie | Yu, Chengyu | Lei, Gang

Article Type: Research Article

Abstract: Based on the non-contact characteristics, active magnetic bearings (AMBs) possess great benefits like no lubrication, high speed, high accuracy and long lifespan. Moreover, the rotor dynamic performance is adjustable and working conditions are monitorable. Nonetheless, AMBs suffer from large power loss and rotor heating. One viable approach is omitting the bias current, i.e., zero-bias AMBs, but this also results in high non-linearity and poor controllability. The common control practices of zero-bias AMBs are based on nonlinear models, for there is only one electromagnet being electrified at any moment to produce a net control force. Here, we propose a linear control …strategy for zero-bias AMB. Assuming that each coil has an average current proportional to the pulse width modulation (PWM) duty cycle, the quantitative relation among the magnetic force, the rotor displacement and the coil current can be acquired. Further, this control algorithm was applied to both the horizontal and the vertical thrust zero-bias AMBs. Experimental results proved the existence of currents in both electromagnetic bearings in the unbalanced state. And the rotor-bearing system restored rapidly to an equilibrium state after sudden disturbances. Overall, this method demonstrates the transition from physics to engineering and shows a good application prospect. Show more

Keywords: Zero-bias magnetic bearing, mathematical model, quantitative control, PWM, power consumption

DOI: 10.3233/JAE-180127

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-22, 2019

Authors: Huang, Lantao | Zou, Jiahao | Zhang, Jing | Zhou, Yihan | Deng, Fangxiong

Article Type: Research Article

Abstract: Eddy current testing is one of electromagnetic methods that are suitable for the inspection of conductive materials. Compared to regular flat coil, rectangular vertical coil can induce a more uniform eddy current distribution in the plate. With other advantages such as directional properties and less sensitive to lift-off variations, the rectangular vertical coil is considered superior to the flat one in certain applications. However, the eddy current of the conventional rectangular vertical coil is comparatively low as the weak coupling between the coil and the conducting plate. It is challenging to achieve high sensitivity and accuracy for the detective sensor …such as GMR or pickup coil. To increase the coupling, a novel probe with a conductive shell is proposed in this study. With the proposed probe, a conductive loop can be formed by the test plate and shell when the shell is in good contact with the test plate during the test. And the conductive loop can effectively increase the coupling and the induced current in the test plate. A simulation model is set up with the finite element method to verify the performance of the designed probe. The results show that the eddy current density in the plate is improved by the proposed probe. When a defect is present, the change of the magnetic flux density and equivalent reactance of the proposed probe are more obvious than the conventional rectangular vertical coil. This improvement is also validated by the experiment of equivalent reactance measurement. Show more

Keywords: eddy current, electromagnetic coupling, finite element analysis

DOI: 10.3233/JAE-190058

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

Authors: Xiong, Linghao | Sun, Zongxiao | Chen, Qingxiao | Xie, Tianyu

Article Type: Research Article

Abstract: Methods of position tracking based on magnetic field monitoring have been widely studied. The application of electromagnetic tracking (EMT) in endoscopic procedures not only has high requirements for position accuracy but also has a great demand for orientation accuracy. Accurate orientation information can provide more clues for shape fitting of the endoscope, especially when coils are placed at the front end of the endoscope for front end shape reconstruction. However, few methods have been proposed to calibrate position and orientation errors at the same time, while most methods are focused on position error correction. This paper presents a new method …showing that by separating the tracking space into grids and calibrating the grid-sensing coil position and orientation parameters (GSCPOP), the position and orientation accuracy can be improved simultaneously by means of iterative computation. Compared to the uncalibrated method, position accuracy showed a 285% improvement, and orientation accuracy showed a 129% improvement. Show more

Keywords: Endoscope, EMT, GSCPOP, calibration method

DOI: 10.3233/JAE-190012

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

Authors: Weichao, Dong | Lei, Du | Xin, Wang | Zheng, Li | Hexu, Sun

Article Type: Research Article

Abstract: To improve the utilization of wind energy, a new type of deflectable double-stators switched reluctance wind power generator is proposed to solve the unicity of the rotor rotation of existing switched reluctance generator (SRG). The generator adopts inner and outer double-stators structure. The multi-degree-of-freedom deflection of the rotating shaft can adapt to different wind directions and is suitable for the combination of electric fields with unstable energy amplitude, which can improve the working efficiency of the generator. The finite element analysis is used to calculate the rotation of the air gap magnetic flux inside the generator rotor, which lays a …foundation for analyzing the vibration displacement of the stator structure. The magnetostriction of stator structure is the main cause of generator vibration. Based on the theory of mechanics, the basic equation of structural mechanics considering magnetostrictive effect is established. Magnetio-solid coupling simulation of internal and external stator and rotor rotation and deflection is carried out using FEA, and the stress distribution and corresponding vibration displacement are obtained. The simulation and analysis results provide a reference for further optimizing the structure of such generators and improving the stability of their operation. Show more

Keywords: Magnetic solid coupling, structural mechanics, vibration displacement, double-stators, magnetostrictive effect

DOI: 10.3233/JAE-190027

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 | Zhao, Dean | Yang, Zebin

Article Type: Research Article

Abstract: The reactive power-based model reference adaptive controller (MRAC) is presented in this paper in detail to estimate rotor resistance online. This controller can maintain rotor flux orientation of bearingless induction motor (BIM) driven by indirect vector control. The instantaneous and steady state reactive power of the rotating part of the BIM are selected in the MRAC as reference model and adjustable model, which automatically protects the entire system from any effects of stator resistance. In addition, this proposed formation of MRAC is independent of the requirement for the estimation of any flux in the calculation process. Therefore, this scheme is …not influenced by the integration, and the problems like saturation and drift can be ignored. At zero speed, this scheme will estimate the rotor resistance more accurately. A speed sensorless scheme can be proposed after adding flux estimators to the MRAC. The effectiveness of the proposed scheme has been verified in MATLAB/SIMULINK. Show more

Keywords: bearingless induction motor, model reference adaptive controller, reactive power, estimation, sensorless

DOI: 10.3233/JAE-190042

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

Authors: Ren, Xiaojun | Feng, Ming | Chen, Shaohua | Miao, Cunxiao | Ren, Yuan

Article Type: Research Article

Abstract: Different from separated magnetic bearing units, combined radial-axial magnetic bearing (CRAMB) has cross coupling problem caused by structure itself. This paper focuses on the study of cross coupling problem for a CRAMB caused by structure itself. An equivalent magnetic circuit model (EMCM) considering the leakage and coupling effects was presented to analyze the mechanism of cross coupling. The analysis results show that due to the influence of magnetic flux leakage and common bias magnetic circuit, cross coupling between axial and radial direction caused by the structure itself of a CRAMB cannot be ignored. The coupling degrees of factors that cause …cross coupling are analyzed based on the combination of EMCM and finite element method (FEM). The analysis results show that the coupling effect caused by axial magnetic flux leakage was most serious. To solve the coupling problem caused by the structure itself, the coupled transfer function is derived. This coupled transfer function has been added in the original controller. Experimental results show that the cross coupling effect was reduced effectively and CRAMB can levitate the rotor at 48000 r/min stably with the improved controller. Show more

Keywords: Cross coupling, combined radial-axial magnetic bearing, decoupling design, magnetic flux leakage

DOI: 10.3233/JAE-190013

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

Authors: Zhai, Fangfang | Liu, Guohai | Xu, Gaohong | Chen, Qian

Article Type: Research Article

Abstract: This paper presents a torque performance improvement method for three-phase consequent-pole permanent magnet (PM) (CPM) machines. The key of this method is to consider torque ripple and output torque simultaneously in CPM machines. This method is realized by adopting optimized six-layer winding and Halbach PMs array. The optimized six-layer winding is employed to reduce the torque ripple by suppressing the even-order harmonics in phase back electromotive forces (back-EMFs). The principles of both even-order harmonics in phase back-EMFs and torque ripple suppression by the optimized six-layer winding are illustrated. There will be a slight reduction of main harmonic back-EMF due to …multilayer winding, then resulting in slightly lower torque production. Hence, the Halbach PMs array are adopted to compensate the output torque. Therefore, the proposed CPM machine has similar output torque with the conventional CPM machine. However, the torque ripple of the proposed CPM is much lower than conventional CPM machine. Meanwhile, the PM utilization ratio can be increased more than 37% compared with the conventional SPM machine. Finally, the theoretical analyses are verified by the finite-element method. Show more

Keywords: consequent-pole, Halbach PMs array, optimized six-layer winding, PM utilization ratio, torque ripple reduction

DOI: 10.3233/JAE-190007

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

Authors: Li, Yanbin | Qu, Boyang | Zhu, Yongsheng | Wan, Yaning | Zhu, Xingheng

Article Type: Research Article

Abstract: With the great concerns on alleviating the environment pollution and traffic congestions, there is a trend for developing light electrical vehicles in urban areas. This paper proposes an outer rotor flux switching permanent magnet machine (FSPMM) for light electric vehicle drive systems. The topology, operational principle and performance of the proposed machine are introduced. Then the procedure for choosing suitable combinations of stator slots and rotor poles is presented by using the sizing equation and finite element method (FEM). It is found that the optimal combination is 6 stator slots and 19 rotor poles for this application. Finally, a 188 W …120 rpm outer rotor FSPMM of the optimal stator/rotor combination is designed and analyzed. The magnetic field distribution and machine parameters are calculated by using FEM, and the performance is predicted based on the current vector control strategy. Show more

Keywords: Flux switching permanent magnet machine (FSPMM), light electrical vehicle, flux weakening ability, finite element method (FEM)

DOI: 10.3233/JAE-190079

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

Authors: Liu, Jinhui | Meng, Dawei | Ai, Mengmeng

Article Type: Research Article

Abstract: In order to improve the reliability of high-voltage motor core, the deteriorated performance parameters of core structure under deteriorating condition are needed. However, the current research on performance reliability mainly focuses on entire motor system, the performance deterioration analysis and fault simulation of the local core structure have not been studied extensively. At the same time, based on the contradiction between calculation ability and accuracy, the calculation of laminated core modeling is large and time-consuming. In this paper, a reliability analysis method of core performance based on multi-scale method and eddy current testing method is proposed. Firstly, the equivalent circuit …network is established according to the multi-scale structure of the core to simulate the performance deterioration process of the core. Then, the deterioration parameters are determined according to the analysis of insulation deterioration, and the three-dimensional eddy current field model and analysis of the core during insulation deterioration are carried out. Finally, the core sensor is designed based on eddy current testing method, and the performance deterioration experiment of the prototype is carried out, and the simulation data and experimental data are compared, the results show that the error between simulation parameters and experimental data is less than 5%, which verifies the validity of the performance reliability analysis method. Show more

Keywords: Eddy current testing method, insulation deterioration, multiscale method, performance deterioration

DOI: 10.3233/JAE-180119

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

Authors: Lin, Ling | Deng, Renjie | Hu, Yanbin | Shan, Hongxuan | Hu, Shunan | Jiao, Hongyu

Article Type: Research Article

Abstract: The two-dimensional viscous space-time conservation element and solution element (CE/SE) method is used to calculate the multi-phase detonation of plasma jet ignition. The effects of viscosity on the detonation flow field are compared with the N–S equation and the Euler equation as the governing equtions, and the effects of the jet temperature, time and initial droplet radius on the deflagration-to-detonation transition are analysed. The results show that the effect of viscosity on the propagation of detonation waves is very small, but the viscosity has certain effects on the detonation parameters. It is possible to significantly shorten the (deflagration-to-detonation transition) DDT …distance of the stable detonation by increasing the temperature and time of the initial jet ignition. When the plasma jet has already fully ignited the detonable mixture, increasing the jet time has little effect on shortening the DDT distance. When the droplet radius is less than 50 μm, the peak pressure of the detonation wave increases with an increase in the droplet radius, and the peak pressure decreases with an increase in the droplet radius when the droplet radius is more than 50 μm. Show more

Keywords: pulse detonation engine, plasma jet, deflagration to detonation transition

DOI: 10.3233/JAE-190046

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

Authors: Li, Zechen | Bao, Xiaohua | Ni, Youyuan | Cheng, Shuai | Liu, Jiwei

Article Type: Research Article

Abstract: Although star-delta winding can improve the efficiency of motors because of a higher fundamental winding coefficient and lower harmonic winding coefficient. The requirement of turns ratio is very strict. If the turns ratio is not ideal, the core loss of the motor cannot be reduced, thus the efficiency will not be improved. In this paper, a design method for converting a star-delta winding of stator in small- and medium-sized motor into the concentric single-double layer star-delta (CSDLSD) winding is introduced and compared with a traditional delta winding and a star-delta winding. Besides, a method is provided to calculate the winding …coefficients of the motors with CSDLSD winding according to the turns number per slot. Harmonic component of magnetic flux density in stator tooth and yoke is consequently reduced, combined with partial core loss calculation method, the core loss is decreased. In addition, the core loss in three-phase induction machines equipped with front three winding types is also been estimated and analyzed. To check the analysis validity, two-dimension (2-D) Finite element method (FEM) is applied on three cage induction motors equipped with different winding types but the same prototypes. Show more

Keywords: Induction machine, CSDLSD winding, winding coefficient, core loss, finite element method

DOI: 10.3233/JAE-190003

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

Authors: Xu, Junqi | Chen, Chen | Sun, Yougang | Rong, Lijun | Lin, Guobin

Article Type: Research Article

Abstract: In this paper, the levitation system of low speed maglev vehicle is taken as the research object, and the suspension principle and adaptive control of the maglev system are discussed. The maglev vehicle is suspended by a combination of multiple electromagnet coils. Therefore, the coupling effect and parameter perturbation can not be considered based on single point levitation. This problem can be solved by building the characteristic model, and the effect of coupling between the electromagnet coils on the suspension performance can be fully considered. Therefore, in order to satisfy the control accuracy of magnetic levitation system, the identification and …adaptive problem of the levitation system of the maglev vehicle are studied according to the characteristic modeling theory. Specifically, the general dynamics model of maglev system should be established and improved. The model is transformed into a characteristic model with suspended clearance as control objective. Then, based on the least-squares method with forgetting factor, the coefficient of characteristic model is identified, and the estimation range of each coefficient is calculated. Finally, numerical simulation and experiment are carried out to verify the control effect. The results show that when the general adaptive control method is used to control the model, the characteristic model can better express the coupling effect between the electromagnet coils. It can express the environment variables and parameter interference more effectively. It is convenient to describe the influence of the coupling between the electromagnet coils in the suspension process, and provide a more effective model basis for further improving the control performance. Show more

Keywords: Maglev vehicle, parameter identification, coupling effect, characteristic modeling, adaptive control

DOI: 10.3233/JAE-190005

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-20, 2019

Authors: Liu, Zenghua | Li, Aili | Bin, Wu | He, Cunfu

Article Type: Research Article

Abstract: Electromagnetic acoustic transducers (EMATs) have been widely applied in non-destructive tests for structural health monitoring. This paper proposes a flexible surface wave electromagnetic acoustic transducer (FSW-EMAT), which uses flexible rubber magnets instead of hard permanent magnets, in order to achieve the defects detection of steel pipe or other ferromagnetic structures with a certain surface curvature. Traditional EMATs mainly consist of three parts: magnet, coil and metal specimen to be tested. Permanent magnets or electromagnets are generally used to produce the strong magnetic flux density. However, the two kinds of magnets are not suitable for the defect detection of metal specimens …with a certain curvature. The proposed FSW-EMAT in this paper adopts a flexible magnet, which is a mixture of rubber and iron powder and has strong flexibility to fit the bent specimen. The proposed FSW-EMAT can be easily applied in the testing of curved structural component and detect axial and circumferential defects by rotating the transducer. Show more

Keywords: Nondestructive testing, electromagnetic acoustic transducer, surface wave, pipe detection

DOI: 10.3233/JAE-190043

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

Authors: Chen, Wei | Wu, Guichu | Li, Yan | Ma, Jien

Article Type: Research Article

Abstract: This paper proposes a coupled finite element analysis of magnetic-thermal fields using an adaptive single-mesh method. To avoid errors from the data transfer and the mesh reconstruction due to different mesh requirements for the magnetic and thermal analysis, this proposed method built single mesh for both analyses. The results of the coupled parameters were transmitted through the single mesh between magnetic and thermal fields. According to the characteristics of the magnetic and the thermal distribution, the master-slave node method was employed to simplify the original element matrix into the magnetic and the thermal matrices, where slave nodes were no longer …solved in the solving process. Results of the slave nodes were expressed by their mater nodes using weight coefficients to regain the results of the original element matrix. A permanent magnet machine was introduced to validate the proposed method with both the commercial software and the experimental tests. Compared to the commercial software, the time cost was reduced by more than 8.0% when a higher accuracy of the thermal analysis was obtained. Show more

Keywords: Coupled analysis, finite element analysis, master-slave method, single mesh, thermal analysis

DOI: 10.3233/JAE-180093

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

Authors: Wang, Huimin | Wang, Tong | Zhang, Xuefeng | Guo, Liyan

Article Type: Research Article

Abstract: As the traditional flux-weakening control strategies have some limitations, such as poor parameter robustness, non-ideal dynamic performance in the constant power region and so on, a new control strategy based on the formula-based feedforward control and the voltage feedback control is proposed. In this strategy, the given reference values of the flux-weakening currents are first calculated by the simplified formulas used in feedforward control, improving the processing speed of the controller by reducing the computational complexity. Then the reference value of the d axis current is compensated by the fuzzy-PI feedback controller, avoiding operating point drifts caused by the …change or inaccurate of parameters in the actual. On this basis, a switching strategy is proposed to achieve a smooth switching between the constant torque and the constant power operation region. The experimental results show that the proposed control strategy has excellent performances, such as strong robustness to parameter perturbation, ideal dynamic performance in the flux-weakening region, smooth switching between the operation regions and so on. Show more

Keywords: Interior Permanent Magnet Synchronous Motor (IPMSM), flux-weakening, fuzzy-PI controller

DOI: 10.3233/JAE-190014

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

Authors: Yin, Rui | Shi, Yan | Di, Changan

Article Type: Research Article

Abstract: Aiming at the problems of complex structure and slow response of the existing hydraulic active suspension actuator, an electromagnetic linear actuator (EMLA) with simple structure, stable operation is designed in this paper. Based on completing the structural design of the EMLA, the two-dimensional finite element model is established by using the finite element software JMAG, and transient analysis of EMLA is carried out, including analyses of no-load magnetic field and thrust force characteristics. The prototype is trial-produced, and its thrust force characteristics are measured on a designed test bench. The experimental values are close to the simulated values, which verifies …the correctness of the model. Finally, by analyzing the variation of the electromagnetic thrust force under different loading currents, this paper obtains the thrust force constant of the EMLA (183N/A). Show more

Keywords: Electromagnetic linear actuator, JMAG finite element, prototype, thrust force characteristics

DOI: 10.3233/JAE-190070

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

Authors: Zhang, Haijun | Zhang, Hua | Ma, Qiang | Han, Haifeng | Wang, Shuhong

Article Type: Research Article

Abstract: Frequency Response Analysis (FRA) is an effective diagnosis approach to detect the winding mechanical faults in power transformer. For understanding the FRA signatures of transformer windings quantitatively, this paper uses the sensitivity method to study the characteristics of frequency response function (FRF) in equivalent circuit of transformer windings. The sensitivity expressions of FRF can be determined by adjoint network method and Tellegen theorem, which reflects the influence of electric parameter changes on FRA signature under winding faults and within a wide-frequency band (10 Hz to 2 MHz). To verify the sensitivity calculation, a two-winding transformer model with seven discs was established and …taken as an example. The results indicate that FRF sensitivity data can provide the valuable insights about how the frequency responses are affected quantitatively with respect to the electric parameter changes or different winding faults. The method and sensitivity analysis discussed in this paper may be useful for diagnosing and predicting different mechanical deformation faults of transformer windings. Show more

Keywords: Transformer winding, equivalent circuit, frequency response, sensitivity analysis

DOI: 10.3233/JAE-190038

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

Article Type: Research Article

Abstract: In order to ensure the safety of fluid flow in deep-water submarine pipelines, a safe and energy-saving built-in skin effect electric heat tracing technology was adopted as the thermal management strategy. By analyzing the multi-physics conditions of the electromagnetic field-temperature field in the heating state of pipelines, the corresponding control equations were derived, and the physical model was established using the transient electromagnetic-temperature coupling field of Ansys Workbench. Simultaneously, we calculated the equivalent parameters of the oil pipeline and heating cable as the load when the system is heated to different temperatures. Thus, the main circuit parameters of the power …supply for the built-in skin effect electric tracing system were designed, thus providing the theoretical guidance for the key performance optimization. For regulating the output power of the built-in skin effect electric heat tracing system, the nonlinear active disturbance rejection control strategy was newly adopted to achieve closed-loop power regulation based on the Buck chopper, and the system has the advantages of fast dynamic response and strong anti-interference ability. Finally, the feasibility of the proposed control system was verified by simulation. Show more

Keywords: Built-in, electric heat tracing system, coupled field, finite element analysis, ADRC

DOI: 10.3233/JAE-190001

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

Authors: Kim, Hong-Kyo | Kang, Beom-Soo | Kim, Jeong

Article Type: Research Article

Abstract: An electromagnetic launcher or accelerator is a useful device for obtaining a wide range of payload velocities. Electromagnetic launchers have smaller space requirements compared to compressed air gas launchers and can use easily obtainable grid electricity to provide thrust in place of a conventional propellant. Despite these advantages, it is difficult to measure launcher muzzle velocity, as the flames and light produced by the muzzle during launch make velocity measurement using a light sensor or high-speed camera impossible. To overcome this problem, B-dot probes can be used to track the projectile position within the launcher by sensing changes in the …magnetic field, which generate an induced voltage in the probe following Faraday’s law. This paper proposes a B-dot probe based method for measuring an electromagnetic launcher’s muzzle velocity. After determining the sensing effect as the probe positions and orientations through numerical simulation, the B-dot probe was used to measure the muzzle velocity, which was compared to a muzzle velocity obtained using a high-speed camera to validate the proposed method. Show more

Keywords: Electromagnetic launching, voltage measurement, velocity measurement, numerical analysis

DOI: 10.3233/JAE-190040

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

Authors: Meng, Fanxu | Zhou, Jin

Article Type: Research Article

Abstract: In this paper, a novel mechanical model based on arc tangent function is established to accurately describe the hysteretic behavior of the squeeze mode Magnetorheological (MR) damper. An improved differential evolution (DE) algorithm, which can avoid the shortage of being easily trapped in a local extremum, is applied to identify the parameters of the model. The dynamical characteristic of the MR damper is experimentally investigated with the help of the MTS machine. The validity of the proposed model is confirmed from a good agreement between the simulations and measured data. In addition, comparative analysis of the simulations with two other …existing models, reveals that the proposed model has a relatively high modelling accuracy with less parameters and explicit physical meaning. Show more

Keywords: Magnetorheological damper, squeeze-mode, characteristic analysis, modeling, differential evolution algorithm

DOI: 10.3233/JAE-190008

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

Authors: Yu, Xudong | Xie, Yuanping | Xiong, Zhenyu | Liu, Chang

Article Type: Research Article

Abstract: A ring laser gyroscope is an optical sensor based on the Sagnac effect. It has many outstanding advantages, such as a short start-up time, a high precision, a wide dynamic range and a stable scale factor. It is insensitive to accelerations and is in wide use in aircraft attitude control, north finding applications including navigation and space missions. The path length transducer in a ring laser gyroscope is required to stabilize the optical path of the laser beams in the cavity. The path length control transducer may tilt in complex environment, which will cause deformation of resonant optical path in …resonant cavity and seriously influence the performance of ring laser gyroscope. Firstly, for the first time, finite element analysis software ANSYS was used to simulate and analyze the small deformation of ring laser gyroscope’s grooved mirror in three directions under typical random vibrational spectra, their value were 2.08" , 2.10" and 1.30" respectively, and the deformation in the diaphragm of resonant cavity was obtained by combining with matrix optical theory quantitatively. Secondly, the influence rule of different radius of curvature and isostructural parameters on the tilt of path length control transducer was sought through quantitative analysis. Finally, combining with the change law of axial displacement in literature [5 ], an evaluation criterion for optimization was given and the optimized parameters were listed for path length control transducer. The tilt was reduced to 0.33" after optimization, which was about 21.4% of current structure. The axial displacement reached 3.89 um, which was 1.84 times of existing structure. The research in the paper could provide reference for the design of path length control transducer of ring laser gyroscope. Show more

Keywords: Ring laser gyroscope, path length control transducer, vibration, finite element analysis

DOI: 10.3233/JAE-190030

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

Authors: Marcsa, Dániel | Veress, Árpád | Szegletes, János | Oroszváry, László | Molnár, László

Article Type: Research Article

Abstract: Passive wheel speed sensors are widely used in automotive applications where knowledge of the rotational velocity of the rotating axes and resistant to environmental impacts are required. This paper presents a general introduction to wheel speed sensor systems and the underlying physical behaviour are explained with the help of three-dimensional time-stepping finite element method. The 3D field simulations well reflect the dynamics of the magnetic field of the real problem and they provide a quantitative understanding of the output signal behaviour concerning model parameter variations. The sensor geometry is analyzed in detail, featuring a study of the influence of the …main parameters. As an outcome of parameter analysis, it was possible to determine the influence of the sensor parameters on the output signal of the sensor. In addition, this study aims to advance the understanding of the physical behaviour of passive wheel speed sensors by three-dimensional nonlinear finite element analysis, which is missing from the literature. Show more

Keywords: Wheel speed sensor, passive sensor, parameter analysis, 3D finite element method

DOI: 10.3233/JAE-190002

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2019

Authors: Zhai, Mingda | Long, Zhiqiang | Li, Xiaolong

Article Type: Research Article

Abstract: The medium-low speed maglev train is an entirely new way of transportation without wheels, and it makes the best of the attraction between the electromagnet and the F-type track to achieve levitation. The magnetic levitation system is considered as the wheels of medium-low speed maglev train, which plays a major role in bearing the weight of vehicle. The theoretical calculation and finite element numerical analysis are performed to calculate the load performance of the magnetic levitation system under different load conditions. The difference of calculation results between the two methods is analyzed and discussed. In addition, a series of load-carrying …tests in vehicles operating on Changsha maglev express is carried out. The experimental results have revealed that the calculation results based on FEM are basically matched with that of actual well conditions. Therefore, the load performance of the magnetic levitation system in medium-low speed maglev train is calculated and evaluated successfully. Show more

Keywords: Medium-low speed maglev train, magnetic levitation system, load performance, FEM, calculation

DOI: 10.3233/JAE-190031

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

Authors: Wang, Zhi | He, Cunfu | Liu, Xiucheng | Zhang, Xiaodong

Article Type: Research Article

Abstract: Ising model is a promising tool for predicting magnetic Barkhausen noise (MBN) signal on Electromagnetic nondestructive evaluation (ENDE). However, theoretical modeling of composite ferromagnetic materials are seldom reported by this model. In order to fill the blank, we extended double Boltzmann transition function incorporate into exchange coupling efficiency (J ) in original Ising model for layered materials MBN simulation. The volume fraction (p ) was considered as a vital parameter, which effect the shape of MBN profiles directly. Experimental study was firstly carry out on layered ferromagnetic material, which consist of laminated different thickness SAE 1065 carbon steel film and …fixed thickness SAE 1045 carbon steel block. For MBN simulation, a step-like transition of J was assumed changes from hard component to soft component in Ising model to obtain the MBN of layered material, and this simulation was perform on Monte Carlo algorithm. The second order Gaussian fitting function was used for extract peak feature of both experimental and simulation MBN. The result show that the MBN peak stand for soft component was gradually vanished with the thickness of SAE 1065 or the volume fraction of hard component increases in experimental and simulation aspect. And, the ratio value of this two fitted peaks with p increases for experimental and simulation were all illustrated an increased trend, which used for qualitative characterize the MBN effect with p changes. The proposed Ising model offer a potential tool for simulate MBN signal of composite ferromagnetic materials, this can be a method to predicting the phase content or volume fraction in such materials. Show more

Keywords: Barkhausen noise, Ising model, layered ferromagnetic materials, Monte Carlo algorithm

DOI: 10.3233/JAE-190034

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

Authors: Li, Jinghe | He, Zhanxiang | Feng, Naixing

Article Type: Research Article

Abstract: Marine controlled source electromagnetic (MCSEM) is an efficient technique for the marine hydrocarbon explorations. Over the past decades, the numerical research on induced polarization (IP) effects in offshore environment is still a intensive topic. Presented here are the results of a 3D new MCSEM forward for IP modeling exercise with the intent of demonstrating the valuable applications of this developed methodology. By using the finite volume method, an analysis on amplitude and phase of electromagnetic field due to the varying IP parameters within the Cole-Cole model is presented. The numerical examples demonstrate that the amplitude and the phase of electromagnetic …field due to the IP effects are subtle, and it is difficult to detect the reservoir hydrocarbon object using such subtle amplitude and phase directly in offshore environment. Based on the assumption that most IP phase spectra can be represented by a linear function of the logarithm of frequency, we apply a two-frequency IP phase decoupling technique for MCSEM data interpretation, which is a plausible example. Numerical IP phase decoupled results for a thin reservoir hydrocarbon object demonstrate the efficiency of the two-frequency IP decoupled technique for MCSEM data interpretation. Show more

Keywords: Marine controlled source electromagnetic, induced polarization, two-frequency decoupled technique, finite volume method, high resistivity reservoir

DOI: 10.3233/JAE-190017

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

Authors: Liu, Xiaomei | Yu, Haitao | Shi, Zhenchuan | Guo, Rong | Liu, Yulei

Article Type: Research Article

Abstract: Research on the relationship between thermal and current density relates the design and application of the electrical machine, which is important in the process of improving motors’ efficiency and working capacity. In this article, an electromagnetic-thermal (EM-thermal) coupled-field analysis and fitting method are adopted to research the relationship among current density, recovery time and duration factor of a permanent magnet synchronous linear motor (PMSLM), and the longitudinal temperature characteristics are analyzed, the simulation results are verified by the experiment. The relationship makes it easier for designers to maximize the torque/power rating by increasing the winding current density within the limit of …temperature and provides a basis for the design and choice of PMLSM under different working conditions. Show more

Keywords: Permanent magnet linear motor, current density, electromagnetic-thermal coupled-field, recovery time, cyclic duration

DOI: 10.3233/JAE-190006

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

Authors: Chen, Yuanyang | Bao, Xiaohua | Gao, Ge | Tang, Yizhui

Article Type: Research Article

Abstract: This paper studies the impact of Poloidal Field (PF) coil current disturbance on plasma shape in Experimental Advanced Superconductive Tokamak (EAST). First, the concept of the free-boundary equilibrium problem is studied. Based on the non-rigid plasma model, a free-boundary equilibrium solver developed in MATLAB software is presented to calculate the flux distribution and plasma profile of EAST plasma equilibrium, and the results are validated against the experiments. Second, given a typical double-null plasma equilibrium, the responses of plasma shape to the lower PF coil currents are computed using the orthogonal test method. The dependences of the elongation and triangularity of …plasma shape on PF coil currents are obtained, showing that the currents in PF6 and PF8 have the greatest impact on triangularity and elongation for lower single-null (LSN) divertor configuration, respectively. And for double-null (DN) divertor plasma configuration, PF5 and PF7 play equally important roles due to the up-down symmetry. The conclusions will be useful for the design of EAST plasma shape feedback control. Show more

Keywords: EAST tokamak, plasma shape response, free-boundary equilibrium calculation, orthogonal test method

DOI: 10.3233/JAE-180133

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2019

Authors: Fenercioğlu, Tevfik Ozan | Yalçinkaya, Tuncay

Article Type: Research Article

Abstract: As an integral part of Strapdown Inertial Navigation Systems, ring laser gyroscopes (RLG) are exposed to joint loading conditions where thermal, static and dynamic loads occur simultaneously. The effects of different loading conditions on overall RLG performance should be addressed in parallel for an optimum design. A crucial aspect in this process is the development of the path length controller (PLC), consisting of a mirror, a composite piezo electric bending actuator and other motion transfer elements. This study presents an analogy between the external loading (static, dynamic, thermal, and vibration) on PLC and the RLG signal stability, which has been …studied only partially in the open literature. 5 different PLC designs are analyzed through finite element method and the results are validated experimentally using the composite piezo electric bending actuator by mode-scanning and PZT feedback tests. Obtained results illustrate the axial and the radial displacement (also named mirror tilt) capacity of different PLC designs. Disruptive effects of radial displacement of the PLC mirrors on RLG signal stability are observed. The study is concluded with the classification of different PLC designs for distinctive loading conditions, which is believed to be valuable for the aerospace industry. Show more

Keywords: Path length controller, ring laser gyroscope, finite element analysis, optimization, laser stability, strapdown inertial navigation system

DOI: 10.3233/JAE-190019

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

Authors: Zhou, Dong | Wei, Min-Xiang | Shi, Li-Hua | Cao, Jie

Article Type: Research Article

Abstract: The mechanism of electromagnetic interference (EMI) is studied for an engine speed acquisition system in this paper. The effect of states and terminal loads is analyzed for the interference signal, which is simulated by using a commercial software. The oscillation of the voltage interference signal is produced by the speed sensor under the radiation of high-altitude nuclear electromagnetic pulse (HEMP), which has been validated by both simulation and experiment. The interference signal can be collected by the speed acquisition system and the normal operation of the engine will be obstructed. The GTEM cell is used for producing the plane wave …for the experiment and the speed acquisition controller is used to test the ability of acquisition for interference signals. Show more

Keywords: Speed acquisition, EMI, HEMP, speed sensor

DOI: 10.3233/JAE-180131

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

Authors: Huang, Lantao | Zhang, Jing | Zou, Jiahao | Zhou, Yihan | Qiu, Li

Article Type: Research Article

Abstract: Electromagnetic forming (EMF) technology uses pulsed current to generate a pulsed electromagnetic force on metal workpiece to accomplish plastic deformation. It is a promising solution for the room temperature processing of lightweight alloy. Coil design is important to energy efficiency and forming performance of EMF. In order to clarify the effect of the equivalent radius of the drive coil on the forming performance, a simulation study is conducted. The preliminary experiment results show good agreement with results of the simulation, and prove the reliability of the simulation model. Then the process of the electromagnetic sheet free bulging is simulated and …analyzed. It is found that the combined action of the boundary constraint and the inertia effect will influence the maximum forming depth. And the maximum values can be obtained at different systems when the ratio of the equivalent coil radius to the active workpiece radius is about 0.68. Show more

Keywords: Electromagnetic forming, coil design, the maximum forming depth

DOI: 10.3233/JAE-190009

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

Authors: Zhang, Yunfeng | Ren, Huan | Zhao, Chenlong | Chen, Jiawen

Article Type: Research Article

Abstract: The three-dimensional model of a lightning rod under a thunderstorm simulated by COMSOL Multiphysics software is established in this paper to study the influencing factors on electric field distortion including the position, height and shape of the lightning rod. In the model, the thunderstorm cloud is equivalent to a plate capacitor; and the building, the lightning rod and the ground are regarded as perfect conductors; whereas their surface potential is zero. The electric field distortion coefficient K is used to measure the influencing parameters on the lightning attachment to the lightning rod. The analysis of model leads to the following …conclusions: influenced by the electric field distortion, a lightning rod at a higher height or at the edge of the building is more likely stuck by the lightning. Considering the effects of the upward connecting leaders in the attachment process, we can further infer that the upward leaders usually start from the tip with greater distortion electric field in the attachment process. However, when the tip of the rod is too sharp, it is often accompanied by the fast attenuation of the electric field, which is not beneficial for the continuous development of the upward connecting leaders. Therefore, in the process of lightning protection design, it is necessary to consider both the position and the height, as well as the shape of the lightning rod in a comprehensive manner. Show more

Keywords: Lightning rod, electric field, distortion coefficient, attachment process

DOI: 10.3233/JAE-180091

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

Authors: He, Tianhu | Ma, Jintao | Li, Yan

Article Type: Research Article

Abstract: In present work, the transient responses of a hollow cylindrical conductor based on the generalized thermoelastic theory with memory-dependent derivative are investigated The conductor with temperature-dependent mechanical properties is subjected to a thermal shock on its internal surface. The hollow cylindrical conductor is placed in a magnetic field along the axial direction of the cylinder. The effects of memory-dependent derivative and temperature-dependent properties influenced by the variable material property factors on the heat conduction and structural responses are emphatically discussed. The coupled governing equations containing time delay factors and kernel functions, which can be chosen freely according to specific problems, …are solved by the Laplace transform together with its numerical inversion. The distributions of the non-dimensional induced electric field, induced magnetic field, hoop stress, radial stress, temperature and displacement at different values of time delay factors, kernel functions and variable material property factors are obtained and illustrated graphically. Finally, some conclusions are summed up, based upon which guidelines may be provided in the design of a hollow cylindrical conductor working in a thermo-mechanical coupling environment. Show more

Keywords: Memory-dependent derivative, hollow cylindrical conductor, induced electric field, induced magnetic field, Laplace transform

DOI: 10.3233/JAE-180124

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

Authors: Zhang, Lei | Zhuan, Xiangtao

Article Type: Research Article

Abstract: Active electromagnetic isolator systems are used to isolate vibration with variable stiffness and damping, flexible controllability, varied control methods and fast response. In order to achieve better vibration isolation performance, an electromagnetic isolator system is designed with small volume and simple structure and the control block diagram with the nonlinear relationships and PID controller is proposed to simulate and verify in this paper. The structure of the electromagnetic isolator system can not only save space, but also provide the controllable electromagnetic force to counteract external disturbances quickly and actively. For improving the vibration isolation performance of the designed electromagnetic isolator …system, a mathematical model which can accurately reflect the relationship between electromagnetic force and coil current and gap is established using structural information and experimental data. A control block diagram of the electromagnetic vibration isolator system containing nonlinear characteristics with PID controller is then designed. The PID control system shows the good performance of active anti-jamming of the designed isolator system. The experimental result demonstrates that the designed electromagnetic isolator system can effectively isolate vibration, and that the control block diagram with PID controller based on the nonlinear system can effectively describe and control the electromagnetic isolator system. The better vibration isolation performance, such as fast response, less overshoot and so on, can be achieved through deliberately designed controllers. Show more

Keywords: Electromagnetic isolator system, vibration control, PID controller, nonlinear system

DOI: 10.3233/JAE-180112

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

Authors: Bafghi, Mohammad Hossein Barzegari | Vahedi, Abolfazl | Alikhani, Arta Mohammad | Takorabet, Noureddine

Article Type: Research Article

Abstract: Torque transmission along a shaft results in the shaft twisting which is negligible in the conventional motors. However, a long and thin shaft is subject to non-negligible twisting effect. This Phenomenon can affect the electromagnetic performance of the motor. In this article, the shaft twisting effect on the electromagnetic behavior of a flux-switching permanent magnet (FSPM) motor is studied. A model of an FSPM motor is proposed to study the electromagnetic performances of the motor. The electromagnetic torque and twisting rate of each point are calculated along the shaft. Then the model results are compared with finite element analysis results …for a long motor. Show more

Keywords: Shaft twisting, mathematical model, long electric motor, flux switching motor

DOI: 10.3233/JAE-180071

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

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

Article Type: Research Article

Abstract: As the focal position of a line-focusing electromagnetic acoustic transducer (LF-EMAT) affects the intensity of the focal signal, we measure the displacement signal and the selection method of the focal line position is then studied in this work to improve the signal intensity and detection precision for a shear-vertical (SV) wave LF-EMAT. We calculate the magnetostatics field and bulk wave propagation utilizing the finite element method (FEM). We simulate the characteristics of the SV wave, and we find that the radiant distance and propagation direction has a great influence on the amplitude of the displacement of the specimen. The superposition …area of SV waves from different sources possesses better focusing ability, and the triangular area (normalized amplitude of the SV waves lower than 10%) near the surface of a specimen should be avoided to be chosen when designing the meander line coils. As for the line-focusing EMAT described in this manuscript, the selection of focal positions for different thickness specimens or detection depth is completely different. Moreover, we perform an experiment to validate the simulation results and lead to a conclusion that the position of the focal point is required to be appropriately close to the excitation coils to enhance the intensity of the signal, while the best focal position should be calculated. Show more

Keywords: EMAT, line focusing, focal position selection, numerical simulation

DOI: 10.3233/JAE-190021

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

Authors: Diaz Florez, Guillermo A. | Mombello, Enrique E. | Voss, Stephan

Article Type: Research Article

Abstract: There are currently two main trends in solving magnetic field problems, numerical methods, of which the Finite Element Method (FEM) is undoubtedly the most popular, and analytical methods, of which there is a great diversity of approaches. The main advantage of numerical methods is their flexibility in modeling complicated geometries; however, its calculation times are generally considerable. Analytical methods attain very short calculation times by sacrificing flexibility. This paper presents the mathematical formulation of a new linear surface element for the semi-analytical solution of axisymmetric magnetic field problems. The importance of this formulation is that it is capable of dealing …with arbitrary geometries while retaining the flexibility of numerical methods with considerably shorter calculation times. The results of the application of the proposed formulation to a case study are presented in the validation section. The results obtained are compared with those calculated with FEM showing an excellent agreement between them. Show more

Keywords: Magnetic field, numerical methods, analytical methods, surface current

DOI: 10.3233/JAE-180107

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-20, 2019

Authors: Wang, Siqi | Liu, Yongkai | Li, Decai | Zhang, Zhili

Article Type: Research Article

Abstract: With the emergence of shared bicycles, people travel is more and more convenient. However, the smart bicycle lock with wireless transceiver system must have sufficient electric energy for normal work. In this paper, a ferrofluid-based planar vibration energy harvester is proposed to convert low-frequency vibration energy into electrical energy. The electromagnetic generator is designed and studied experimentally. The energy harvesting system is installed in the backseat and the front basket turning with the front fork, respectively. Experimental results indicate the collected energy is 0.010 J in the backseat and 0.020 J in the front basket for the maximal experiment distance of 1.16 km, …respectively, which can meet the demand of the smart bicycle lock. Show more

Keywords: Ferrofluid, energy harvester, shared bicycle, vibration

DOI: 10.3233/JAE-180123

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2019

Authors: Klach, Moufida | Aloui, Helmi | Neji, Rafik

Article Type: Research Article

Abstract: This paper presents the modeling by Magnetic Equivalent Circuit model (MEC) of a Simple Excited Automotive Alternator (SE2A) where DC-excitation winding is transferred from rotor side to stator one rather than in conventional automotive claw pole alternators, to overcome the disadvantages of the ring-brush system. Following the resolution of the MEC using Newthon-Raphson numerical method, the alternator performances at both no-load and under resistive load regimes are achieved considering the saturation effect. It has been found that alternator’s performances carried out using the proposed MEC are with closed proximity to experimental records on a built prototype of the considered alternator. …Then, a modified SE2A is proposed by the integrating Barium ferrites permanent magnets between adjacent rotor claws in order to combine the high-energy density of permanent magnets with the commonly controllability. This configuration is named the Hybrid Excited Automotive Alternator (HE2A). The improvement of its topology performance is provided through the optimization of the device topology based on a Sequential Quadratic Programming (SQP) coupled to a magnetic equivalent circuit considering iron losses minimization case. It has been found that the efficiency of the alternator could be improved especially at high speed rate. Show more

Keywords: Claw pole alternator, simple excitation, experimental tests, hybridization, optimization, iron losses

DOI: 10.3233/JAE-170021

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

Authors: Xu, Yongming | Ai, Mengmeng | Wang, Wenyi | Wang, Yaodong

Article Type: Research Article

Abstract: Due to the high rotational speed, the permanent magnet of surface-mounted high-speed permanent magnet generator is easily damaged by the centrifugal force. So a high strength alloy sheath is installed to protect the permanent magnet. The material, thickness and eddy current loss of the composite sheath of the high-speed permanent magnet generator with rotor strength constraint is studied thoroughly in this paper. Generator rotor strength under different limit conditions is calculated by numerical analysis method based on the thick-cylinder theory of elastic mechanics. Various methods have been used to reduce the eddy current. The composite sheath of high-speed permanent magnet …generator on the basis of rotor strength constraint is presented. Change of the material, thickness of each layer of the sheath is determined by calculation of stress and eddy current loss and optimized design of composite sheath with reasonable stress distribution and lower eddy current loss. Strength test of prototype rotor is carried out. Show more

Keywords: Electromagnetic high-speed permanent magnet generator, strength constraint, composite sheath, eddy current loss

DOI: 10.3233/JAE-180117

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

Authors: He, Yichao | Liang, Guanqun | Xue, Bing | Peng, Zhizhao | Wei, Yintao

Article Type: Research Article

Abstract: Magnetorheological (MR) damper is one of the key technologies in the field of semi-active suspensions. However, the dynamic model and control strategy are not yet well established. A unified MR damper model and its inverse characterization are proposed to investigate MR damper dynamics. First, a novel unified model is proposed to describe the shear term of the MR damper force. This forward unified MR damper model uses one set of parameters to describe all MR force behavior under all currents and velocities, which agrees well with experimental data. Then, an inverse MR model based on the adaptive neuro-fuzzy inference system …(ANFIS) technique has been established, where the precise training data are obtained from the proposed unified hysteretic model. A clear step-wise modeling process is proposed to decrease coupling degree of system which can be beneficial to improve inverse modeling efficiency. The inverse MR model is used for a semi-active suspension control, which can obtain the excitation current, exactly tracking the desired damping force computed by suspension control algorithm. Finally, validation of the proposed ANFIS inverse model has been conducted by comparison with three traditional empirical inverse approaches. The results reveal that the ANFIS inverse model could achieve much more tracking capability for the desired damping force and thus contributes to the development of semi-active suspension controllers. Show more

Keywords: Magnetorheological damper, unified model, inverse characteristics, adaptive neuro-fuzzy inference system, suspension controller

DOI: 10.3233/JAE-180114

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-21, 2019

Authors: Zhang, Xiao | Li, Changxing | Wang, Xiaoguang | Zhao, Yun | Li, Liang

Article Type: Research Article

Abstract: The controllability of the distribution of Lorentz force on tube is poor in electromagnetic forming when using a conventional single coil forming system. To solve this issue, a triple-coil forming system was developed in this work, which includes three coils and two independent power supplies. To validate the effectiveness of the system, experimental studies for the forming of aluminium tube AL6061 under different conditions were carried out. Results showed that when using this novel forming system, the deformation behavior of tube can be obviously improved, including larger deformation depth, better performance of sizing, and lower occurrence of cracking.

Keywords: Electromagnetic forming, lorentz force distribution, deformation depth, sizing, cracking

DOI: 10.3233/JAE-180122

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

Authors: Yao, Xing-Yan | Pecht, Michael

Article Type: Research Article

Abstract: Magnetorheological (MR) dampers are important devices for reducing and controlling vibration. Dynamic response time is one of the key factors that determines the control ability and application of the MR damper. Metal foam MR dampers are potentially superior to conventional dampers due to their low cost and fast response. The dynamic response time of metal foam MR dampers is distinct from conventional dampers. In this paper, the effects of different metal foam materials on the dynamic response time of metal foam dampers are studied. Three response time parameters were defined, and an experimental system including a DC motor, force sensor, …damper, and time relay was designed to collect dynamic response time parameter values using metal foam Cu and Ni, respectively. The experimental results show that the response time of MR dampers is faster using Ni rather than Cu metal foam due to the different permeability of the materials. The magnetic resistance model and Ansys simulation further prove that magnetic flux density is the main contributor to the differences in response time. Show more

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

DOI: 10.3233/JAE-190022

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

Authors: Coufal, Oldřich | Bátora, Branislav | Radil, Lukáš | Toman, Petr

Article Type: Research Article

Abstract: A method is proposed for the calculation of current density in a long solid metallic conductor placed in an external variable magnetic field. The external magnetic field is perpendicular to the conductor and constant on straight lines parallel to the conductor. The conductor is passive, connected to neither a voltage source nor a current source. It is assumed that the external magnetic field is quasi-stationary and is not affected by the magnetic field of the currents induced in the conductor under examination. The frequency of external field does not exceed 1 MHz and the displacement current is neglected. The proposed method …enables the calculation of current density not only in the steady state but also in the case that the external field has an arbitrary time-dependent course. Results are given of the calculation of current density in conductors with symmetrical and unsymmetrical cross section, with constant and non-constant resistivity in the conductor cross section, for both homogeneous and non-homogeneous external steady-state sinusoidal field, and for switching the external sinusoidal field on and off. Show more

Keywords: Applied classical electromagnetism, magnetic induction, eddy currents, numerical simulation

DOI: 10.3233/JAE-180118

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