International Journal of Applied Electromagnetics and Mechanics - Volume 51, issue 1

Authors: Shi, Junjie | Fan, Cuiying | Zhao, Minghao | Yang, Jiashi

Article Type: Research Article

Abstract: We studied thickness-shear vibration frequencies and modes in a rectangular AT-cut quartz plate resonator with ring electrodes. The electrodes are also rectangular, with their central parts missing and thus form rectangular ring electrodes. It was found that the vibration tends to be trapped in the electrode area and decays away from the electrode edges. By properly designing the electrode dimensions, the vibration can be made nearly uniform in the central part of the plate. This is particularly suitable for resonator-based sensor applications where the sensitivity is determined theoretically from the uniform vibration distribution of pure thickness-shear modes in an unbounded …plate. Show more

Keywords: Quartz, plate, resonator, sensor

DOI: 10.3233/JAE-150091

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 1-10, 2016

Authors: Ren, Long | Chen, Renwen | Xia, Huakang | Zhang, Xiaoxiao | Xu, Dongxia

Article Type: Research Article

Abstract: To scavenge vibration energy from industrial application environments and supply power to wireless sensor networks, this paper proposes an electromagnetic vibration energy harvester (VEH) using an optimized transducer. The VEH consists of a planar spring, an axially magnetized magnet assembly, a coil assembly and an outer casing. An analytical model is proposed to analyze and optimize the electromagnetic transducer and improve its energy harvesting performance. Finite element analysis is then used to verify the model. An optimized prototype is manufactured and fabricated, and finally tested by experiment. The experimental results indicate that an open-circuit voltage of 2.2 V can be …achieved when the VEH is excited by the vibration with a resonant frequency of 22.4 Hz and an acceleration amplitude of 100 mg. When the optimal resistor of 200 Ω is connected to the coil assembly, its maximum load power of 0.29 mW can be achieved, which can meet the needs of many industrial sensors as well as wireless communication modules and guarantee their intermittent work at least. Show more

Keywords: Vibration energy harvester, electromagnetic, optimization, finite element analysis

DOI: 10.3233/JAE-150099

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 11-19, 2016

Authors: Liu, Shuang | Wu, Zheng | Shi, Yatao | Wang, Jinjin

Article Type: Research Article

Abstract: This paper focuses on sliding bifurcation of an electromechanical coupling drive system drived by AC synchronous motor containing friction under external excitation along with the changes of external excitation frequency. Considering the mixed friction on load side, the electromagnetic coupling torque provided by motor side and the external disturbance torque on load side, the dynamical equation of an electromechanical coupling drive system containing friction under external excitation can be deduced according to Newton's laws. The stability of periodic solutions in the system is analyzed with Floquet theory. The Filippov convex method is used to extend the system and theoretical conditions …of the stick-slip motion are given to numerically predict the sliding bifurcation. The influence of external excitation frequency on the dynamic behavior of drive system is observed and the dynamic behavior of system is verified whether it meets the conditions of sliding bifurcation. Numerical simulations are also given to confirm the results. Show more

Keywords: Sliding bifurcation, electromechanical coupling system, friction, external excitation

DOI: 10.3233/JAE-150155

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 21-36, 2016

Authors: Yao, Hongyang | Li, Hongmei | Zhou, Yanan

Article Type: Research Article

Abstract: Transverse flux permanent magnet machine (TFPM) is well known for its achievable high torque density and flexible topologies, which makes it especially suitable for wind power generation, electric vehicle and direct drive area. Existing TFPM topologies, however, are subject to high flux leakage and cogging torque. This paper deals with the design and optimization of a three phase surface mounted transverse flux permanent machine (SM-TFPM) to reduce flux leakage and cogging torque, the solutions of adjusting the interval between magnets and inserting auxiliary stator are suggested to realize the restriction of both flux leakage and cogging torque. The finite element …analysis (FEA) results show the obvious effects, and the FEA design is validated via prototype experiment by using TMS320F28335 based controller and induction machine load. Based on the abovementioned researches, a further multi-objective optimization is applied by using differential evolution (DE) algorithm and the optimization results are compared with the previous design to demonstrate the improved performance Show more

Keywords: SM-TFPM, auxiliary stator, cogging torque, flux leakage, differential evolution

DOI: 10.3233/JAE-150159

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 37-49, 2016

Authors: Liu, Zehui | Lu, Ming | Li, Qing | Lv, Zhongbin | Chang, Afei | Pang, Kai | Zhao, Shujie

Article Type: Research Article

Abstract: A direct coupling method is developed for coupling meshless methods such as the MLPG and FEM. The radial point interpolation method with polynomial terms (RPIMp) which lead to a shape function that indeed obeys the Kronecker delta property are used to approximate the trial functions in the MLPG. This important property make the MLPG method could couple the FEM directly as other coupling method must use additional techniques. An electromagnetic problem governed by the Poisson's equation and nonlinear ionized field examples are given in this paper. The results, which are compared with both the exact solutions and solutions obtained from …the FEM, show that the method in this paper could couple the MLPG FEM directly without any additional numerical techniques. The paper offer an coupling method by making full use of the MLPG and FEM advantages to deal with engineering problems and more difficult problem geometries. Show more

Keywords: Meshless local petrov-galerkin method (MLPG), meshless, finite element method (FEM), coupling method

DOI: 10.3233/JAE-150161

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 51-59, 2016

Authors: Liu, Chien-Sheng | Chang, Yu-Hao | Li, Hong-Fei

Article Type: Research Article

Abstract: The smart cell phone market has rapid growth in recent years and cell phone camera modules have strong requirement for capturing images and communication in our daily use. Accordingly, in the present study, a novel compact voice coil motor (VCM) actuator is proposed for auto-focusing (AF) of cell phone camera modules. Compared to conventional VCM actuators with open-loop position control mechanism, the proposed VCM actuator is featured with absence of spring plates. In the proposed approach, the magnetic restoring force is used to replace the restoring force of the spring plates in the open-loop control VCM actuators. The motivation of …this study is to characterize the performance of the proposed VCM actuator using simulation methods and then evaluate experimentally this device using a laboratory-built prototype. The results show that the proposed VCM actuator has the sizes of 8.5 mm × 8.5 mm × 7.5 mm, the maximal input current of 40 mA, the maximal response time of 10 ms, and the average measured Lorentz force of 2200 mgw for the input current of 40 mA in its whole displacement (stroke of 0.4 mm), and it operates the AF function well. Show more

Keywords: Auto-focusing, voice coil motor, actuator, linear motors, phone cameras, open-loop control

DOI: 10.3233/JAE-150166

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 61-70, 2016

Authors: Zhang, Yi | Yuan, Ping | Ye, Wenjun | Zhu, Huacheng | Yang, Yang | Huang, Kama

Article Type: Research Article

Abstract: Magnetrons are widely applied to the rapidly developing microwave industries as high power microwave sources. However, the free-running magnetron produces unstable frequency and wideband spectrum, which limits the magnetron's further applications for coherent power-combining and scientific fields. In this paper, by introducing a feedback loop with a high Q filter into the magnetron system, the output frequency can be qusai locked around the center frequency of the filter if the loop phase is between (2k-1 2 ) π and (2k+1 2 )π. Moreover, the output frequency bandwidth of the self-injection magnetron is narrowed and the …phase noise is also reduced. In order to find out the requirements for the qusai locked magnetron and the effects of the parameters on the qusai locked results, a theoretical model based on the combination of the equivalent circuit of the magnetron and the transfer function of the filter has been developed. Furthermore, numerical analyses illustrate the effect of the loop phase, Q value and the injection ratio on the output results. The experiments validate the conclusions obtained in the theoretical analyses. Show more

Keywords: Magnetron, self-injection, qusai locking, noise reduction, high Q filter

DOI: 10.3233/JAE-150172

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 71-81, 2016

Authors: Kim, Chan-Ho | Jung, Sang-Yong | Kim, Yong-Jae

Article Type: Research Article

Abstract: The magnetic gear that solves the physical contact problem of the mechanical gear has advantage of no mechanical friction loss, very little noise and vibration, and no need for lubricant. Due to this unique non-contact characteristic, the magnetic gear which is capable of non-contact torque transmission has replaced mechanical gear. However, the magnetic gear with a high gear ratio is disadvantageous to implement the exact gear ratio because the number of rotor poles increases. Therefore, dual-stage type magnetic gear was proposed in order to distributes the gear ratio by using two magnetic gears as to the mechanical gear is used …the multi-stage in order to implement the high gear ratio. The dual-stage type magnetic gear can improve the power density and efficiency compared to the single-stage magnetic gear. Also, the dual-stage type magnetic gear can be designed differently permanent magnet type because the use of the two magnetic gear. Therefore, in this paper, permanent magnet material of second magnetic gear was not changed and only permanent magnet material of first magnetic gear was changed to bonded NdFeB magnet or ferrite magnet from sintered NdFeB magnet. Transfer torque and magnetic field analysis method for dual-stage magnetic gear was used 2-D numerical analysis. Show more

Keywords: Transfer torque, magnetic gear, gear ratio, rare-earth magnets, non rare-earth magnets, power transmission, finite element method

DOI: 10.3233/JAE-150177

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 83-89, 2016