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

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