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DEVELOPMENT OF THE CONTROL METHODOLOGY OF THE GIANT MAGNETOSTRICTIVE ACTUATOR BASED ON magnetic flux density

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 359-362页

作者： JiaZhenyuan YangXing ShiChun GuoOongming SchoolofMechanicalEngineering DalianUniversityofTechnologyDalian116024China DepartmentofPrecisionInstrumentsandMechnology TsinghuaUniversityBeijing100084China SchoolofMechanicalEngineenng DalianUniversityofTechnologyDalian116024China

According to the principle of the magnetostriction generating mechanism, thecontrol model of giant magnetostriction material based on magnetic field and the control method withmagnetic flux density are developed. Furthermore, this control method is used to develop a giantmagnetostrictive micro-displacement actuator (GMA) and its driving system. Two control methods whosecontrol variables are current intensity and magnetic flux density are compared with each other byexperimental studies. Finally, effective methods on improving the linearity and control precision ofmicro-displacement actuator and reducing the hysteresis based on the controlling magnetic fluxdensity are obtained.

关键词： Giant magnetostriction magnetic flux density Control method Micro-displacement actuator

magnetic flux density Modeling Method of Maglev System

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Magnetic Flux Density Modeling Method of Maglev System

Mechanical properties and microstructural evolution of rheocast A356 semi-solid slurry prepared by annular electromagnetic stirring

第36届中国控制会议

作者： Qiang Chen Siyang Zhou Jie Li College of Mechatronics Engineering and Automation National University of Defense Technology

ISBN: (纸本)9781538629185

Modeling is the basis work of the analysis and design of a control system,and models obtained by different modeling methods have different characteristics.In the maglev system,current is generally used as a state to model.Through analysis and comparison in this paper,compared with modeling with current state,using magnetic flux density as a state to model the maglev system,the model is much simpler,the linear model is more accurate and more close to the real system.Besides,based on the model built by magnet flux density state method,state feedback is more beneficial to the stabilization of the system,the control performance is better and the coupling interference between suspension points is smaller.

关键词： Maglev Model magnetic flux density

来源： cnki会议评论

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China Foundry 2023年第4期20卷 315-328页

作者： Mohammad Taghi Asadi Khanouki Department of Materials and Metallurgy Engineering Shahid Bahonar University of KermanP.O.Box ***KermanIran Mineral Industries Research Center(MIRC) Shahid Bahonar University of KermanP.O.Box ***KermanIran

Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase annular electromagnetic stirring(A-EMS)technique under different conditions.The effects of stirring current,pouring temperature and stirring time on microstructural evolution,mean particle size,shape factor and solid fraction were investigated.The rheocasting process was carried out by using a drop weight setup and to inject the prepared semi-solid slurry in optimal conditions into the step-die cavity.The filling behavior and mechanical properties of parts were studied.Microstructural evolution showed that the best semi-solid slurry which had fine spherical particles with the average size of~27μm and a shape factor of~0.8 was achieved at the stirring current of 70 A,melt pouring temperature of 670℃,and stirring time of 30 s.Under these conditions,the step-die cavity was completely filled at die preheating temperature of 470℃.The hardness increases by decreasing step thickness as well as die preheating temperature.Moreover,the tensile properties are improved at lower die preheating temperatures.The fracture surface,which consists of a complex topography,indicates a typical ductile fracture.

关键词： semi-solid slurry annular electromagnetic stirring rheocast A356 aluminum alloy microstructural evolution mechanical properties magnetic flux density

A Novel High Performance magnetic Gear with Auxiliary Silicon Steel Sheet

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CES Transactions on Electrical Machines and Systems 2022年第2期6卷 201-206页

作者： Can Tan Libing Jing College of Electrical Engineering and New Energy China Three Gorges UniversityYichang 443002China

magnetic gear is a transmission device with novel structure.It uses the principle of magnetic field modulation to transmit torque.In view of the magnetic leakage of the magnetic gear in the process of rotation and cannot be eliminated,a magnetic gear model with auxiliary silicon steel sheet is proposed.Based on the conventional magnetic gear structure,the silicon steel sheet is placed outside the permanent magnet of the outer rotor.The magnetization mode of the outer rotor permanent magnet is tangential magnetization,and the spoke structure is adopted,and the inner rotor PMs is surface mounted and magnetized in the radial magnetization.The improved model is simulated by finite element method under three-dimensional conditions,and the electromagnetic performances of the model are optimized.Compared with the conventional magnetic gear model,the improved model has good performance,which improves the transmission capacity of output torque and reduces torque ripple.It is a great significance to improve the performance of magnetic gear.

关键词： magnetic gear magnetic flux leakage magnetic field modulation magnetic flux density Torque

Development of a Miniature Permanent magnetic Circuit for Nuclear magnetic Resonance Chip

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Chinese Journal of Mechanical Engineering 2013年第4期26卷 689-694页

作者： LU Rongsheng YI Hong WU Weiping NI Zhonghua Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments Southeast University

The existing researches of miniature magnetic circuits focus on the single-sided permanent magnetic circuits and the Halbach permanent magnetic circuits. In the single-sided permanent magnetic circuits, the magnetic flux density is always very low in the work region. In the Halbach permanent magnetic circuits, there are always great difficulties in the manufacturing and assembly process. The static magnetic flux density required for nuclear magnetic resonance(NMR) chip is analyzed based on the signal noise ratio(SNR) calculation model, and then a miniature C-shaped permanent magnetic circuit is designed as the required magnetic flux density. Based on Kirchhoff’s law and magnetic flux refraction principle, the concept of a single shimming ring is proposed to improve the performance of the designed magnetic circuit. Using the finite element method, a comparative calculation is conducted. The calculation results demonstrate that the magnetic circuit improved with a single shimming has higher magnetic flux density and better magnetic field homogeneity than the one improved with no shimming ring or double shimming rings. The proposed magnetic circuit is manufactured and its experimental test platform is also built. The magnetic flux density measured in the work region is 0.7 T, which is well coincided with the theoretical design. The spatial variation of the magnetic field is within the range of the instrument error. At last, the temperature dependence of the magnetic flux density produced by the proposed magnetic circuit is investigated through both theoretical analysis and experimental study, and a linear functional model is obtained. The proposed research is crucial for solving the problem in the application of NMR-chip under different environmental temperatures.

关键词： nuclear magnetic resonance microfluidic chip permanent magnet magnetic flux density

Simulation research on effect of magnetic nanoparticles on physical process of magneto–acoustic tomography with magnetic induction

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Chinese Physics B 2018年第10期27卷 378-385页

作者：闫孝姮张莹刘国强 Faculty of Electrical and Control Engineering Liaoning Technical University Institute of Electrical Engineering Chinese Academy of Sciences Faculty of Electrical and Control Engineering Liaoning Technical University School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences

Magneto–acoustic tomography with magnetic induction（MAT-MI） is a multiphysics coupled imaging technique that is combined with electrical impedance tomography and ultrasound imaging. In order to study the influence of adding magnetic nanoparticles as a contrast agent for MAT-MI on its physical process, firstly, we analyze and compare the electromagnetic and acoustical properties of MAT-MI theoretically before and after adding magnetic nanoparticles, and then construct a two-dimensional（2 D） planar model. Under the guidance of space-time separation theory, we determine the reasonable simulation conditions and solve the electromagnetic field and sound field physical processes in the two modes by using the finite element method. The magnetic flux density, sound pressure distribution, and related one-dimensional（1 D）, 2 D, and three-dimensional（3 D） images are obtained. Finally, we make a qualitative and quantitative analysis based on the theoretical and simulation results. The research results show that the peak time of the time item separated from the sound source has a corresponding relationship with the peak time of the sound pressure signal. At this moment, MAMPTMI produces larger sound pressure signals, and the sound pressure distribution of the MAMPT-MI is more uniform, which facilitates the detection and completion of sound source reconstruction. The research results may lay the foundation for the MAT-MI of magnetically responsive nanoparticle in subsequent experiments and even clinical applications.

关键词： magneto-acoustic tomography with magnetic induction magnetic nanoparticles magnetic flux density sound pressure

Compute extremely low-frequency electromagnetic field exposure by 3-D impendance method

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The Journal of China Universities of Posts and Telecommunications 2007年第3期14卷 113-116页

作者： HAN Yu-nan LV Ying-hua ZHANG Hong-xin Beijing University of Posts and Telecommunications Beijing 100876 ChinaAerospace Science and Technology Group Beijng 100076 China

A 3-D impedance method has been introduced to compute the electric currents induced in a human body exposed to extremely low-frequency electromagnetic field. The 3-D impedance method has been deduced from Maxwell equations and is put into the computation and simulation effectively to the visible human body model, which has 196×114×626 cells and more than 40 types of tissues. As the result, two representative cases are investigated. One is exposure of the human body to 100 μT （1 000 mG）, the limit recommended by the International Commission on Non-Ionizing Radiation Protection for the public and the other one is the exposure of human body to 0.4 laT （4 mG）, the level at which a statistical link appears with a doubled risk of development of childhood leukaemia. The distribution of induced current density can be obtained and the maximum of induced current are found to be 16 mA/m^2 and 0.07 mA/m^2.

关键词： 3-D impedance method induced current magnetic flux density visible human body model extremely low frequency （ELF）

Propagation effects of low frequency electromagnetic waves in production well

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Petroleum Science 2012年第2期9卷 182-191页

作者： Song Xijin Guo Baolong Dang Ruirong Wang Xuelong Institute of Intelligent Control and Image Engineering Xidian UniversityShaanxi 710071China Key Laboratory of Photoelectric Logging and Detecting of Oil and Gas Ministry of EducationXi'an Shiyou UniversityShaanxi 710065China College of Computer Science&Technology Shaanxi University of TechnologyShaanxi 710048China

The frequency domain electromagnetic method has already been widely used for tomographic imaging or electromagnetic well logging. However, different from open hole logging, the metal casing existing in production well logging has a strong shielding effect on the electromagnetic waves, thus bringing some difficulties to the application of the frequency domain electromagnetic method in production well logging. According to the relation of the field source geometry to the ring around the mandrel, the general expressions of frequency domain electromagnetic responses in axially symmetrical layered conductive medium are deduced. The propagation effects caused by the low-frequency electromagnetic waves in cased hole are also analyzed. The distribution curves of eddy current density and magnetic flux density along the radial direction in the mandrel indicate that the eddy loss within the mandrel is proportional to the transmission signal frequency and the mandrel conductivity. The secondary field responses of different casing materials show that the transmission frequency has an important effect on the ability of electromagnetic waves penetrating the metal casing. The transmission frequency should be ultra-low in order to enable the electromagnetic signal to penetrate the casing easily. The numerical results of frequency responses for different casing physical parameters show that the casing thickness has a significant impact on the choice of the transmission frequency. It is also found that the effect of the casing radius on the transmission frequency can be neglected.

关键词： Propagation effects eddy current density magnetic flux density production well frequency response

The Nonzero External magnetic Field of Long Solenoids

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Journal of Electromagnetic Analysis and Applications 2022年第2期14卷 19-30页

作者： Shiwei Ye Beijing Computational Science Research Center Beijing China

A widespread assertion has existed for a long time, believing the external field of an infinitely long solenoid should be zero, but it is proofed to be wrong in this work. The components of magnetic flux density of current-carrying, closely wound cylindrical solenoids are calculated. At a distant field point, the external field definitely has a nonzero component, being equal to that of a straight wire of equal length. Since this equivalence is length-independent, it still holds true for ideal solenoids having infinite length. Hence the incorrect and still spreading inference about long solenoids should be rectified. Furthermore, theoretical and experimental discussions involving solenoids should be reviewed again carefully.

关键词： Solenoid magnetic flux density Vector Potential Aharonov-Bohm Effect