• Title/Summary/Keyword: magnetic parameters

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Quasi-3D analysis of Axial Flux Permanent Magnet Rotating Machines using Space Harmonic Methods (공간고조파법을 이용한 축 자속 영구자석 회전기기의 준(準)-3D 특성 해석)

  • Choi, Jang-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.5
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    • pp.942-948
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    • 2011
  • This paper deals with characteristic analysis of axial flux permanent magnet (AFPM) machines with axially magnetized PM rotor using quasi-3-D analysis modeling. On the basis of magnetic vector potential and a two-dimensional (2-D) polar-coordinate system, the magnetic field solutions due to various PM rotors are obtained. In particular, 3-D problem, that is, the reduction of magnetic fields near outer and inner radius of the PM is solved by introducing a special function for radial position. And then, the analytical solutions for back-emf and torque are also derived from magnetic field solutions. The predictions are shown in good agreement with those obtained from 3-D finite element analyses (FEA). Finally, it can be judged that analytical solutions for electromagnetic quantities presented in this paper are very useful for the AFPM machines in terms of following items : initial design, sensitivity analysis with design parameters, and estimation of control parameters.

Electro-magneto-elastic analysis of a three-layer curved beam

  • Arefi, Mohammad;Zenkour, Ashraf M.
    • Smart Structures and Systems
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    • v.19 no.6
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    • pp.695-703
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    • 2017
  • In this paper, based on first-order shear deformation theory, the governing equations of motion for a sandwich curved beam including an elastic core and two piezo-magnetic face-sheets are presented. The curved beam model is resting on Pasternak's foundation and subjected to applied electric and magnetic potentials on the piezo-magnetic face-sheets and transverse loading. The five equations of motion are analytically solved and the bending and vibration results are obtained. The influence of important parameters of the model such as direct and shear parameters of foundation and applied electric and magnetic potentials are studied on the electro-mechanical responses of the problem. A comparison with literatures was performed to validate our formulation and results.

DESIRABLE PARAMETER IDENTIFICATION FOR THE IMPLEMENTATION OF IDEAL PASSIVE FAULT CURRENT LIMITER FOR THE PROTECTION OF POWER SEMICONDUCTOR DEVICES

  • Mukhopadhyay, S.C.;Iwahara, M.;Yamada, S.;Dawson, F.P.
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.859-864
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    • 1998
  • Compact and small size, reliable and failsafe operation and low cost featuring fault current limiter causing the designer to take a close look into the use of passive fault current limiter(FCL) for the protection of power semiconductor devices in power electronic systems. This paper has identified the main parameters responsible for the development of ideal passive magnetic current limiter. The effect of those parameters on the range of operation and the voltage-current characteristics of the magnetic current limiter has been studied using tableau approach. Desirable characteristics are discussed and the simulation results are presented.

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Multi-Observations of Magnetic Cloud

  • Sung, Suk-Kyung;Marubashi, Katsuhide;Lee, Dong-Hun
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.89.2-89.2
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    • 2011
  • The geometry of an MC (magnetic cloud) in the interplanetary space can be estimated by the magnetic flux rope model. But the single point observation in the interplanetary space near the Earth is scanty to comprehend the global configuration of MC because the MC is considered a huge loop extending from the Sun with both legs rooted on the Sun. If the MC is observed at two different locations sufficiently far away from each other, it may provide the global configuration of the MC. In this study, we model the MC which is observed two different locations using a simple straight cylinder model. The MC model fit parameters are the flux rope axis orientation (${\Theta}$, ${\phi}$), the intensity of the magnetic field at the flux rope axis ($B_0$), the radius of the MC ($R_0$), and the impact parameter (p), etc. With the MC model fit parameters we look into the difference between two observed MC geometries and also calculate the magnetic flux and helicity of the MC.

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On-line Magnetic Distortion Calibration Method for a Magnetometer (지자기 센서의 온라인 왜곡 보정기법)

  • Kim, Tae-Yeon;So, Chang-Ju;Lyou, Joon
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.9
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    • pp.819-822
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    • 2012
  • This paper describes an on-line magnetic distortion calibration procedure for a magnetometer. The horizontal magnetic field is calculated through the earth magnetic field sensed by 3-axes magnetometer. The ellipse equation is derived from a set of horizontal magnetic field data using least square method and calibration parameters are determined. The calibration process is performed iteratively until parameters are not renewed, and experimental results show the effectiveness of the devised method.

Analysis of Magnetic Permeability Spectra of Metamaterials Composed of Cut Wire Pairs by Circuit Theory

  • Lim, Jun-Hee;Kim, Sung-Soo
    • Journal of Magnetics
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    • v.21 no.2
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    • pp.187-191
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    • 2016
  • Retrieving the equivalent electromagnetic parameters (permittivity and permeability) plays an important role in the research and application of metamaterials. Frequency dispersion of magnetic permeability has been theoretically predicted in a metamaterial composed of cut wire pairs (CWP) separated by dielectric substrate on the basis of circuit theory. Magnetic resonance resulting from antiparallel currents between the CWP is observed at the frequency of minimum reflection loss (corresponding to absorption peak) and effective resonator size can be determined. Having calculated the circuit parameters (inductance L, capacitance C) and resonance frequency from CWP dimension, the frequency dispersion of permeability of Lorentz like magnetic response can be predicted. The simulated resonance frequency and permeability spectra can be explained well on the basis of the circuit theory of an RLC resonator.

Design and Characteristic Analysis of LSM for High Speed Train System using Magnetic Equivalent Circuit

  • Ham, Sang-Hwan;Cho, Su-Yeon;Kang, Dong-Woo;Lee, Hyung-Woo;Chan, Hong-Soon;Lee, Ju
    • International Journal of Railway
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    • v.3 no.1
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    • pp.14-18
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    • 2010
  • This paper describes design and characteristic analysis of long primary type linear synchronous motor (LSM) for high speed train system. LSM is designed using loading distribution method and magnetic equivalent circuit. For characteristic analysis of LSM, analytical and numerical methods are applied. Analytical method for solving the magnetic field distribution of the analytic model is based on the Maxwell’s equations. Using the characteristic equation and magnetic equivalent circuit, we analyze the effect of variation of parameters, and then we validate the result by comparing with numerical method by finite element method (FEM). We compare the analytical method with numerical method for analyzing the effect by variable parameters. This result will be useful of design and forecast of performance without FEM.

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Design of Neodymium Permanent Magnetic Core using FEM (유한요소법을 이용한 네오디움 영구자석의 코어 설계)

  • Hur, Kwan-Do;Ye, Sang-Don
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.5
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    • pp.70-75
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    • 2014
  • Permanent magnets have recently been considered as device that can be used to control the behavior of mechanical systems. Neodymium magnets, a type of permanent magnet, have been used in numerous mechanical devices. These are permanent magnets made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. The magnetic selection, magnet core design and mechanical errors of the magnetic component can affect the performance of the magnetic force. In this study, the coercive force, residual induction, and the dimensions of the design parameters of the magnet core are optimized. The design parameters of magnet core are defined as the gap between the magnet and the core, the upper contact radius, and the lower thickness of the core. The force exercised on a permanent magnet in a non-uniform field is dependent on the magnetization orientation of the magnet. Non-uniformity of the polarization direction of the magnetic has been assumed to be caused by the angular error in the polarization direction. The variation in the magnetic performance is considered according to the center distance, the tilt of the magnetic components, and the polarization direction. The finite element method is used to analyze the magnetic force of an optimized cylindrical magnet.

A Study on Deduction of Equivalent Circuit Parameters and Verification of Control Algorithm of Thrust Force of a Small-scaled LIM for a Railway Transit (철도차량용 선형유도전동기 축소형 모델의 등가회로 파라미터 도출 및 추진력 제어 알고리즘 검증 연구)

  • Park, Chan-Bae;Mok, Hyung-Soo;Lee, Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.7
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    • pp.1248-1254
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    • 2010
  • Authors conducted a deduction of some parameters using the magnetic equivalent circuit method and a verification study of the thrust force control algorithm of a rotary-typed small-scaled linear induction motor for a railway transit. In a LIM, it is possible to express the parameters of the magnetic equivalent circuit into a function of the shape of the secondary aluminium plate and the airgap between the LIM primary core and the secondary aluminium plate. It means that the LIM properties can be changed considerably by the shape of the secondary aluminium plate and the airgap between the LIM primary core and the secondary aluminium plate. So, authors analyzed a tendency of changes of the magnetic equivalent circuit parameters and the LIM characteristics by changing of the airgap of the secondary aluminium plate of a rotary-typed small-scaled LIM. And authors conducted a verification study of the indirect vector control algorithm with constant slip frequency by using the rotary-typed small-scaled LIM tester set on the basis of the calculated LIM parameters. Finally authors accomplished a research on applicability for LIM railway transit.

TEMPORAL VARIATIONS OF THE GLOBAL SEISMIC PARAMETERS OF HD 49933 OVER A MAGNETIC CYCLE

  • Kim, Ki-Beom;Chang, Heon-Young
    • Journal of The Korean Astronomical Society
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    • v.54 no.4
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    • pp.129-137
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    • 2021
  • It has been established that the acoustic mode parameters of the Sun and Sun-like stars vary over activity cycles. Since the observed variations are not consistent with an activity-related origin, even Sun-like stars showing out-of-phase changes of mode frequencies and amplitudes need to be carefully studied using other observational quantities. In order to test whether the presumed relations between the global seismic parameters are a signature of the stellar activity cycle, we analyze the photometric light curve of HD 49933 for which the first direct detection of an asteroseismic signature for activity-induced variations in a Sun-like star was made, using observations by the CoRoT space telescope. We find that the amplitude of the envelope significantly anti-correlates with both the maximum frequency of the envelope and the width of the envelope unless superflare-like events completely contaminate the light curve. However, even though the photometric proxy for stellar magnetic activity appears to show relations with the global asteroseismic parameters, they are statistically insignificant. Therefore, we conclude that the global asteroseismic parameters can be utilized in cross-checking asteroseismic detections of activity-related variations in Sun-like stars, and that it is probably less secure and effective to construct a photometric magnetic activity proxy to indirectly correlate the global asteroseismic parameters. Finally, we seismically estimate the mass of HD 49933 based on our determination of the large separation of HD 49933 with evolutionary tracks computed by the MESA code and find a value of about 1.2M and a sub-solar metallicity of Z = 0.008, which agrees with the current consensus and with asteroseismic and non-asteroseismic data.