The Experts below are selected from a list of 13104 Experts worldwide ranked by ideXlab platform

Seok-myeong Jang - One of the best experts on this subject based on the ideXlab platform.

  • torque analysis and measurements of cylindrical air gap synchronous permanent magnet couplings based on analytical Magnetic field calculations
    IEEE Transactions on Magnetics, 2013
    Co-Authors: Jangyoung Choi, Hyeonjae Shin, Seok-myeong Jang
    Abstract:

    This paper presents the torque analysis and measurements of cylindrical air-gap synchronous permanent magnet couplings based on analytical Magnetic field calculations. Employing a Magnetic Vector Potential and a 2-D analytical model with two polar coordinate systems, we obtain the Magnetic fields produced by permanent magnets. Then, the analytical torque solutions are derived using these Magnetic field solutions and a Maxwell stress tensor method. The analytical results are validated by nonlinear 2-D and 3-D finite element results. Finally, torque measurements are presented to show the effectiveness of the analysis.

  • analytical torque calculations and experimental testing of permanent magnet axial eddy current brake
    IEEE Transactions on Magnetics, 2013
    Co-Authors: Hyeonjae Shin, Hanwook Cho, Jangyoung Choi, Seok-myeong Jang
    Abstract:

    This paper discusses the braking torque and normal force analysis of axial flux permanent magnet (AFPM)-type eddy current brakes (ECB) on the basis of an analytical field computation using a space harmonic method. On the basis of the Magnetic Vector Potential and a 2D polar coordinate system, permanent magnets considering the eddy current effect are obtained. Additionally, by utilizing the derived analytical field solutions, the braking torque and normal force are predicted. Finite element analysis is employed to confirm the validity of the analysis and compare it with the experimental results obtained from the prototype AFPM-type ECB.

  • analytical Magnetic torque calculations and experimental testing of radial flux permanent magnet type eddy current brakes
    Journal of Applied Physics, 2012
    Co-Authors: Jangyoung Choi, Seok-myeong Jang
    Abstract:

    This paper reports on analytical Magnetic torque calculations and experimental tests of a radial flux permanent magnet (RFPM)-type eddy current brake (ECB). Analytical solutions for permanent magnet-generated Magnetic fields that consider the eddy current reaction are obtained by using a Magnetic Vector Potential and a two dimensional (2D) polar coordinate system. On the basis of these solutions, the analytical expressions for a Magnetic torque are also derived. All analytical results are validated extensively by non-linear finite element calculations. In particular, Magnetic torque measurements are obtained in tests to confirm the analyses. Finally, practical issues related to the analytical study of RFPM-type ECBs are fully discussed.

  • torque analysis of axial flux pm type eddy current brake based on analytical field computations
    International Conference on Electrical Machines and Systems, 2011
    Co-Authors: Jangyoung Choi, Hyeonjae Shin, Yuseop Park, Seok-myeong Jang
    Abstract:

    This paper deals with torque analysis of axial flux permanent magnet (AFPM) type eddy current brake (ECB) based on analytical field computation. On the basis of a Magnetic Vector Potential and a two-dimensional (2-D) polar coordinate system, analytical solutions for normal and tangential flux density due to permanent magnet (PM) considering eddy current effect are obtained. And then, using derived analytical field solutions, braking torque and normal force characteristics according to rotor speed are also predicted. A three-dimensional (3-D) finite element (FE) analysis is employed to confirm the validity of analyses. Finally, this paper investigates influence of design parameters on the performances of the AFPM type ECB.

  • electroMagnetic analysis and control parameter estimation of moving coil linear oscillatory actuator
    Journal of Applied Physics, 2006
    Co-Authors: Seok-myeong Jang, Jangyoung Choi, Sangsub Jeong
    Abstract:

    This paper deals with an electroMagnetic analysis and control parameter estimation of a moving-coil linear oscillatory actuator (MCLOA). Analytical solutions for electroMagnetic characteristics of the MCLOA are obtained from transfer relations derived in terms of a Magnetic Vector Potential and two-dimensional (2D) rectangular coordinate systems. And then, on the basis of 2D analytical solutions, control parameters such as the thrust constant, the back-emf constant, and winding inductances are estimated. Finally, analytical results for both electroMagnetic characteristics and control parameters of the MCLOA are validated extensively by finite element analyses. In particular, test results such as static thrust, resistance, and inductance measurements are given to confirm the analyses.

Jangyoung Choi - One of the best experts on this subject based on the ideXlab platform.

  • Parametric analysis and optimized torque characteristics of a coaxial Magnetic gear based on the subdomain analytical model
    AIP Advances, 2017
    Co-Authors: Kyunghun Shin, Hanwook Cho, Hyungil Park, Jangyoung Choi
    Abstract:

    This paper presents the torque calculation and parametric analysis of a coaxial Magnetic gear (CMG). We obtained analytical Magnetic field solutions produced by permanent magnets based on a Magnetic Vector Potential. Then, the analytical solutions for Magnetic torque were obtained. All analytical results were extensively validated with nonlinear two-dimensional finite element analysis. Finally, using the derived analytical Magnetic torque solutions, we carried out parametric analysis to determine the influence of the design parameters on the CMG’s behavior.

  • torque analysis and measurements of cylindrical air gap synchronous permanent magnet couplings based on analytical Magnetic field calculations
    IEEE Transactions on Magnetics, 2013
    Co-Authors: Jangyoung Choi, Hyeonjae Shin, Seok-myeong Jang
    Abstract:

    This paper presents the torque analysis and measurements of cylindrical air-gap synchronous permanent magnet couplings based on analytical Magnetic field calculations. Employing a Magnetic Vector Potential and a 2-D analytical model with two polar coordinate systems, we obtain the Magnetic fields produced by permanent magnets. Then, the analytical torque solutions are derived using these Magnetic field solutions and a Maxwell stress tensor method. The analytical results are validated by nonlinear 2-D and 3-D finite element results. Finally, torque measurements are presented to show the effectiveness of the analysis.

  • analytical torque calculations and experimental testing of permanent magnet axial eddy current brake
    IEEE Transactions on Magnetics, 2013
    Co-Authors: Hyeonjae Shin, Hanwook Cho, Jangyoung Choi, Seok-myeong Jang
    Abstract:

    This paper discusses the braking torque and normal force analysis of axial flux permanent magnet (AFPM)-type eddy current brakes (ECB) on the basis of an analytical field computation using a space harmonic method. On the basis of the Magnetic Vector Potential and a 2D polar coordinate system, permanent magnets considering the eddy current effect are obtained. Additionally, by utilizing the derived analytical field solutions, the braking torque and normal force are predicted. Finite element analysis is employed to confirm the validity of the analysis and compare it with the experimental results obtained from the prototype AFPM-type ECB.

  • analytical Magnetic torque calculations and experimental testing of radial flux permanent magnet type eddy current brakes
    Journal of Applied Physics, 2012
    Co-Authors: Jangyoung Choi, Seok-myeong Jang
    Abstract:

    This paper reports on analytical Magnetic torque calculations and experimental tests of a radial flux permanent magnet (RFPM)-type eddy current brake (ECB). Analytical solutions for permanent magnet-generated Magnetic fields that consider the eddy current reaction are obtained by using a Magnetic Vector Potential and a two dimensional (2D) polar coordinate system. On the basis of these solutions, the analytical expressions for a Magnetic torque are also derived. All analytical results are validated extensively by non-linear finite element calculations. In particular, Magnetic torque measurements are obtained in tests to confirm the analyses. Finally, practical issues related to the analytical study of RFPM-type ECBs are fully discussed.

  • torque analysis of axial flux pm type eddy current brake based on analytical field computations
    International Conference on Electrical Machines and Systems, 2011
    Co-Authors: Jangyoung Choi, Hyeonjae Shin, Yuseop Park, Seok-myeong Jang
    Abstract:

    This paper deals with torque analysis of axial flux permanent magnet (AFPM) type eddy current brake (ECB) based on analytical field computation. On the basis of a Magnetic Vector Potential and a two-dimensional (2-D) polar coordinate system, analytical solutions for normal and tangential flux density due to permanent magnet (PM) considering eddy current effect are obtained. And then, using derived analytical field solutions, braking torque and normal force characteristics according to rotor speed are also predicted. A three-dimensional (3-D) finite element (FE) analysis is employed to confirm the validity of analyses. Finally, this paper investigates influence of design parameters on the performances of the AFPM type ECB.

Charles A Bouman - One of the best experts on this subject based on the ideXlab platform.

  • model based iterative reconstruction of magnetization using Vector field electron tomography
    IEEE Transactions on Computational Imaging, 2018
    Co-Authors: Aditya K Mohan, K C Prabhat, Charudatta Phatak, Marc De Graef, Charles A Bouman
    Abstract:

    Vector field electron tomography (VFET) is extensively used for three-dimensional (3-D) imaging of Magnetic materials at nanometer resolutions. The conventional approach is to reconstruct and visualize the Magnetic Vector Potential or the Magnetic field associated with the sample. There is a lack of algorithms capable of reconstructing the 3-D distribution of magnetization from VFET data. Unlike Magnetic Vector Potential and Magnetic field, magnetization is a fundamental physical property of the sample that does not extend beyond the dimensions of the sample. We present a model-based iterative reconstruction algorithm (MBIR) that reconstructs the magnetization by minimizing a cost function consisting of a forward model term and a prior model term. The forward model uses the physics of imaging to model the VFET data as a function of the magnetization, and the prior model enforces sparsity in the magnetization reconstruction. We then formulate an optimization algorithm based on the theory of alternate direction method of multipliers to minimize the resulting MBIR cost function. Using simulated and real data, we show that our algorithm accurately reconstructs both the magnetization and the Magnetic Vector Potential.

  • 3d reconstruction of the Magnetic Vector Potential using model based iterative reconstruction
    arXiv: Computation, 2017
    Co-Authors: K C Prabhat, Aditya K Mohan, Charudatta Phatak, Charles A Bouman, Marc De Graef
    Abstract:

    Lorentz Transmission Electron Microscopy (TEM) observations of Magnetic nanoparticles contain information on the Magnetic and electrostatic Potentials. Vector Field Electron Tomography (VFET) can be used to reconstruct electroMagnetic Potentials of the nanoparticles from their corresponding LTEM images. The VFET approach is based on the conventional filtered back projection approach to tomographic reconstructions and the availability of an incomplete set of measurements due to experimental limitations means that the reconstructed Vector fields exhibit significant artifacts. In this paper, we outline a model-based iterative reconstruction (MBIR) algorithm to reconstruct the Magnetic Vector Potential of Magnetic nanoparticles. We combine a forward model for image formation in TEM experiments with a prior model to formulate the tomographic problem as a maximum a-posteriori probability estimation problem (MAP). The MAP cost function is minimized iteratively to determine the Vector Potential. A comparative reconstruction study of simulated as well as experimental data sets show that the MBIR approach yields quantifiably better reconstructions than the VFET approach.

Edward J. Park - One of the best experts on this subject based on the ideXlab platform.

  • Analytical modeling of eddy current brakes with the application of time varying Magnetic fields
    Applied Mathematical Modelling, 2016
    Co-Authors: Kerem Karakoc, Afzal Suleman, Edward J. Park
    Abstract:

    Abstract Eddy current brakes have a number of Potential advantages, i.e. contactless operation, faster response, reduced number of components and easy implementation of various controllers. However, the braking torque generation is limited at low speeds. Here, to increase the braking torque generation, time varying field application is studied. A new analytical model is derived for in-depth theoretical analysis and future controller design purposes. The braking torque generated is calculated using Magnetic Vector Potential and eddy currents. Then, this model was validated using an accurate finite element model. Results show that the braking torque increases with the application of time-varying fields.

Aditya K Mohan - One of the best experts on this subject based on the ideXlab platform.

  • model based iterative reconstruction of magnetization using Vector field electron tomography
    IEEE Transactions on Computational Imaging, 2018
    Co-Authors: Aditya K Mohan, K C Prabhat, Charudatta Phatak, Marc De Graef, Charles A Bouman
    Abstract:

    Vector field electron tomography (VFET) is extensively used for three-dimensional (3-D) imaging of Magnetic materials at nanometer resolutions. The conventional approach is to reconstruct and visualize the Magnetic Vector Potential or the Magnetic field associated with the sample. There is a lack of algorithms capable of reconstructing the 3-D distribution of magnetization from VFET data. Unlike Magnetic Vector Potential and Magnetic field, magnetization is a fundamental physical property of the sample that does not extend beyond the dimensions of the sample. We present a model-based iterative reconstruction algorithm (MBIR) that reconstructs the magnetization by minimizing a cost function consisting of a forward model term and a prior model term. The forward model uses the physics of imaging to model the VFET data as a function of the magnetization, and the prior model enforces sparsity in the magnetization reconstruction. We then formulate an optimization algorithm based on the theory of alternate direction method of multipliers to minimize the resulting MBIR cost function. Using simulated and real data, we show that our algorithm accurately reconstructs both the magnetization and the Magnetic Vector Potential.

  • 3d reconstruction of the Magnetic Vector Potential using model based iterative reconstruction
    arXiv: Computation, 2017
    Co-Authors: K C Prabhat, Aditya K Mohan, Charudatta Phatak, Charles A Bouman, Marc De Graef
    Abstract:

    Lorentz Transmission Electron Microscopy (TEM) observations of Magnetic nanoparticles contain information on the Magnetic and electrostatic Potentials. Vector Field Electron Tomography (VFET) can be used to reconstruct electroMagnetic Potentials of the nanoparticles from their corresponding LTEM images. The VFET approach is based on the conventional filtered back projection approach to tomographic reconstructions and the availability of an incomplete set of measurements due to experimental limitations means that the reconstructed Vector fields exhibit significant artifacts. In this paper, we outline a model-based iterative reconstruction (MBIR) algorithm to reconstruct the Magnetic Vector Potential of Magnetic nanoparticles. We combine a forward model for image formation in TEM experiments with a prior model to formulate the tomographic problem as a maximum a-posteriori probability estimation problem (MAP). The MAP cost function is minimized iteratively to determine the Vector Potential. A comparative reconstruction study of simulated as well as experimental data sets show that the MBIR approach yields quantifiably better reconstructions than the VFET approach.