International Journal of Applied Electromagnetics and Mechanics - Volume 62, issue 1

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. 62, no. 1, pp. 1-12, 2019

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

Article Type: Research Article

Abstract: Electromagnetic acoustic transducers (EMATs) have been widely applied in nondestructive testings and 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. 62, no. 1, pp. 13-29, 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. 62, no. 1, pp. 31-43, 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. 62, no. 1, pp. 45-57, 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. 62, no. 1, pp. 59-71, 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. 62, no. 1, pp. 73-92, 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. 62, no. 1, pp. 93-108, 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. 62, no. 1, pp. 109-125, 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. 62, no. 1, pp. 127-143, 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. 62, no. 1, pp. 145-159, 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. 62, no. 1, pp. 161-172, 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. 62, no. 1, pp. 173-189, 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. 62, no. 1, pp. 191-205, 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. 62, no. 1, pp. 207-219, 2019