• Title, Summary, Keyword: Maxwell stress tensor

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Modeling of a bearingless motor using distributed magnetic circuit (분산 자기 회로를 이용한 베어링리스 모터의 모델링)

  • 박창용;박수진;노명규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.212-216
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    • 2004
  • Bearingless motors are the rotational electric machine which utilize a common magnetic structure for rotation and magnetic suspension. Since the bearing function is combined with the motor, the shaft length can be shortened resulting in higher critical speeds. Relationship between suspension force and current of bearingless motor is clearly derived by prior research. However, relationship between displacement of rotor and suspension force is not precisely defined. In this paper, we present model of bearingless motor describing the radial force variation due to the movement of the rotor. Using a distributed magnetic circuit and maxwell stress tensor, we derived a mathematical expression for the radial force. For a slotless bearingless motor, we are able to find an analytical model presented in the form of stiffness. For a slotted motor, we can compute the stiffness by semi-analytical analysis. This model is validated by a finite-element-analysis.

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A Study on a Novel Method for Electromagnetic Force Computation based on Continuum Design Sensitivity Analysis (연속체 설계 민감도해석을 이용한 새로운 전자기력 계산방법에 관한 연구)

  • Kim Dong-Hun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.6
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    • pp.287-293
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    • 2005
  • Equations have been derived for computing electromagnetic forces by using the Continuum Design Sensitivity Analysis based on the Continuum Mechanics and the Virtual Work Principle. The resultant expressions have similar terms relating to the Korteweg-Holmholz force density, Maxwell Stress Tensor and Magnetic Charge Method but numerical implementation of the proposed scheme leads to efficient calculation and improved accuracy. In addition, the method can be easily applied to computing the magnetic force distribution as well as the global force. Results show the aforementioned advantages in comparison with the conventional methods.

A Study on the Driving Principles of a Novel Non-contact Surface Actuator Using Combination of Magnetic Force (비접촉 평면 구동기의 자기력 조합 방식 구동 원리)

  • Jung, Kwang-Suk;Baek, Yoon-Su
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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    • pp.115-121
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    • 2001
  • In micro automation technology, the concurrent realization of a high resolution and a large operating rage has been achieved by a dual actuator, usually called by piggy-back system, conventionally. But, because of its manufacturing cost, the complexity of control, and the limit of overall bandwidth, the contract-free and single servo actuators have been suggested with specific applications. In this paper, we suggest a novel non-contact surface actuator suing combination of the Lorentz force and the magnetized force, and discuss the actuating principles including an analytical approach. Differently from the existing planar system, an operating range of the suggested system can be expanded by an additional attachment of active elements. Therefore, it is estimated to be suitable for the next-generation moving system.

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Analysis of Characteristics in Switched Reluctance Motor According to the Variation of Rotor Shape (회전자 형상 변화에 따른 스위치드 릴럭턴스 전동기의 특성 해석)

  • Lim, S.B.;Park, J.W.;Choi, J.H.;Chun, Y.D.;Kim, Y.H.;Lee, J.
    • Proceedings of the KIEE Conference
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    • pp.596-598
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    • 2001
  • This paper presents an analysis of the characteristics in switched reluctance motor (SRM). 2D finite element method (FEM) considering the iron saturation and the actual switching circuit of the SRM drive is applied for the dynamic analysis. The influence of the rotor shape on the radial force and torque ripple is investigated and the optimal shape of rotor pole is proposed to enhance the torque. The radial force characteristics acting on the surface of teeth is investigated by using the Maxwell's magnetic stress tensor method.

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A study of normal force and its effect in a SPMPM with Halbach array (Halbach 배열 영구자석형 Planar Motor의 수직적 해석 및 영향)

  • Huang, Rui;Zhou, Jianpei;Han, Kwang-Kyu;Kim, Gyu-Tak
    • Proceedings of the KIEE Conference
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    • pp.86-88
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    • 2006
  • This paper presents normal force analysis and its minimization of synchronous permanent magnet planar motor(SPMPM) with Halbach array. Firstly, the experimental error of thrust is investigated and it is caused by the friction force generated by normal force. Then normal force Is analyzed by Maxwell stress tensor. At last, the normal force is minimized by using genetic algorithm and it is decreased from 672.83[N] to 144.24[N] remarkably.

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Body Force Distribution in Permanent Magnet Motors (영구자석 전동기에서의 체적력 분포 관찰)

  • Choi, Hong-Soon;Kim, Young-Sun;Park, Il-Han
    • Proceedings of the KIEE Conference
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    • pp.659-660
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    • 2006
  • 전기기기에서의 전자기력 계산은 기기의 성능뿐 아니라 기계적 변형, 진동을 예측하는 주요 파라미터이다. 지금까지는 Maxwell stress tensor법이나 자하법, 가상변위법등에 의해 전체 전자기력 또는 토크를 계산하여 왔으나, 이 방법들은 모두 분포 전자기력을 계산할 수 없었다. 본 논문에서는 기기 내부의 체적 전자기력분포를 계산하는 방법을 제시하고, 그 예로써 영구자석형 전동기의 전자기력 분포를 보여준다. 체적력의 계산은 저자에 의해 제안 된 가상공극법에 기반하여 구현할 수 있다.

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Comparison of Force Calculation Methods in Finite Element Method (유한요소법을 이용한 전자기력 계산방법의 비교)

  • Xiuke, Yan;Ryu, Jae-Seop;Koh, Chang-Seop
    • Proceedings of the KIEE Conference
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    • pp.100-103
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    • 2001
  • The magnetic force calculation methods, the Maxwell's stress tensor method, virtual work method, and nodal force method are reviewed. The methods are applied to the magnetic force calculation of 2D linear and nonlinear Problems. As the results the convergence of the methods as the number of elements increases, accuracy of the methods, and integral path dependence of the methods are discussed. Finally some recommendations on the usage of the methods, including the determination of the integral path, are given.

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Analysis of Radial Force Density as a Vibration Source in Brushless DC Motor Using 3D Equivalent Magnetic Circuit Network Method (3차원 등가자기회로망법을 이용한 Brushless DC 모터의 진동원으로서의 Radial Force Density 해석)

  • Chun, Y.D.;Hur, J.;Yoon, S.B.;Hong, J.P.;Hyun, D.S.
    • Proceedings of the KIEE Conference
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    • pp.171-173
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    • 1997
  • This paper presents analysis of the radial force density in brushless DC motor of which distribution is not uniform in the axial direction. The analysis considering 3D shape of teeth and overhang is not only important but essential to calculate the radial force density that acts on the teeth of stator, because it is frequent source of vibration and changes at the end of teeth. For the analysis, a new 3D equivalent magnetic circuit network method taking into account movement of the rotor without remesh is proposed. The radial force density is calculated by Maxwell stress tensor and analyzed by discrete Fourier transform.

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Electromagnetic Force Density Analysis of Magnetic System (자기시스템의 전자력 밀도 해석)

  • Lee, Se-Hee;Choi, Myung-Jun;Kim, Chang-Wook;Park, Il-Han
    • Proceedings of the KIEE Conference
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    • pp.201-203
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    • 1997
  • As electromagnetic systems have the complexity and high performance, they should be designed to take into account the vibration, noise and strain of mechanical aspect as well as electrical problems. Until now, mechanical approaches have been tried to analyze the subject, but it is difficult to figure out the matter in mechanical consideration. Because they are mainly related to electromagnetic phenomena. This paper deals with the theories and numerical formulations of magnetic force density. Several methods are applied to an actuator and DC machine model to calculate magnetic force density. These results are compared with the total force obtained by maxwell stress tensor and virtual work principle.

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Comparison of Controller Performance for Hybrid-PM Suspension System (하이브리드 부상시스템에서의 부상제어기 성능비교)

  • Sung, So-Young;Lee, Un-Ho;Park, Jong-Won;Jang, Seok-Myeong;Lim, Y.G.
    • Proceedings of the KIEE Conference
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    • pp.752_753
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    • 2009
  • This paper deals with controller design and dynamic simulation of hybrid magnetic bearing. The flux density at air-gap is obtained from system modeling which considers permanent magnet and electro magnet. The vertical force is derived yb that flux density using maxwell's stress tensor.

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