• Title/Summary/Keyword: Space harmonic analysis method

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Comparison and Analysis of Armature Reaction Magnetic Field of Linear Generator with Coreless/Cored Type Three Phases Concentrated Winding by using Space Harmonic Analytical Method (3상 집중권 권선을 갖는 코어리스/코어드 타입 리니어 발전기의 공간고조파 해석법을 이용한 전기자 반작용 자계특성 해석)

  • Seo, Sung-Won;Koo, Min-Mo;Kang, Han-Bit;Choi, Jang-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.1
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    • pp.64-71
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    • 2015
  • This paper deals with analysis of armature reaction magnetic field of linear generator with three phases coreless/cored type concentrated winding. On the basis of a magnetic vector potential and Maxwell's equations, governing equations to predict armature reaction field are derived, and current density modeling is also performed analytically by using the Fourier series expansion. The analytical method used in this paper is confirmed by comparing with finite element analysis results.

Analysis on the alternating torque characteristics of capacitor motor with windings not in quadrature (비대칭축콘덴서 전동기의 진동토오크 특성의 해석)

  • 오경열
    • 전기의세계
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    • v.26 no.4
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    • pp.41-53
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    • 1977
  • With the equivalent series circuit analyzed aby revolving field theory and drawn by using the equivalent circuit constant ratios in capacitor motor with windings not in quadrature having space harmonics in its magnetic field (the above ratios are the equivalent circuit constants for the fundamental flux to the magnetizing reactance of the circuit), the equation for the alternating torque with twice line freequency in the motor is directly derived, and the alternating torque is measured with the self-made stator vibration angle amplitude measuring apparatus that is composed of a pickup, filter, photoelectric pickoff etc. The measured values satisfactorily compared with computed values. The properties of the alternating torque characteristics for respective harmonic fluxes and the r5esultant alternating torque characteristic, the effects of the alternating torque characteristics for respective harmonic fluxes on the resultant alternating torque characteristic, the effects of the variation in the motor constants and the equivalent circuit constant ratios for the fundamental flux on the alternating torque characteristics for respective harmonic fluxes and the resultant alternating torque characteristic, are made clear, applying the equation. There exist the optimum values of the motor constants and the equivalent circuit constant ratios for the fundamental flux for decreasing the alternating torque, and the value could be determined in design by the method presented in this paper.

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Cogging Torque Reduction Design of Permanent Magnet Motor Using Analytical Method (해석적인 방법을 이용한 Cogging Torque 저감을 위한 영구자석형 전동기 형상 설계)

  • Fang, Liang;Lee, Byeong-Hwa;Hong, Jung-Pyo
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.676_677
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    • 2009
  • In this paper, an analytical method used for predicting the magnetic field distribution and cogging torque characteristic in a permanent magnet synchronous motor (PMSM) is presented. The magnetic field is analyzed with the space harmonic analysis, and the cogging torque is calculated based on the air-gap field distribution and slot-opening effect considered by relative permeance. The validity of the presented analytical method is confirmed by 2-dimensional finite element analysis (FEA). Then this analytical method combines with response surface methodology (RSM) is applied to the prototype PMSM model rebuilding in order to minimize the cogging torque. Finally, an optimized PMSM model is built and the cogging torque reduction is confirmed by FEA.

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An Optimized Control Method Based on Dual Three-Level Inverters for Open-end Winding Induction Motor Drives

  • Wu, Di;Su, Liang-Cheng;Wu, Xiao-Jie;Zhao, Guo-Dong
    • Journal of Power Electronics
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    • v.14 no.2
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    • pp.315-323
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    • 2014
  • An optimized space vector pulse width modulation (SVPWM) method with common mode voltage elimination and neutral point potential balancing is proposed for an open-end winding induction motor. The motor is fed from both of the ends with two neutral point clamped (NPC) three-level inverters. In order to eliminate the common mode voltage of the motor ends and balance the neutral point potential of the DC link, only zero common mode voltage vectors are used and a balancing control factor is gained from calculation in the strategy. In order to improve the harmonic characteristics of the output voltages and currents, the balancing control factor is regulated properly and the theoretical analysis is provided. Simulation and experimental results show that by adopting the proposed method, the common mode voltage can be completely eliminated, the neutral point potential can be accurately balanced and the harmonic performance for the output voltages and currents can be effectively improved.

Microcomputer-Based Maximum Efficiency Control of a Synchronous Motor. (마이크로 컴퓨터를 이용한 동기 전동기의 최대 효율제)

  • Hyun, Dong-Seok;Park, Min-Ho
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.12
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    • pp.874-887
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    • 1987
  • The efficiency of a synchronous motor can be substantially improved by controlling armature voltage, field excitation, and load angle on optimum values which yield minimum input power at any specified torque and speed. This improvement is particularly noticeable in the case of light loads. In addition, the control of armature input voltage improves the power factor at which the motor operates. Employed in the analysis is a new equivalent circuit model of the motor which incorporates the frequency dependent nature of the motor parameters and the effects of iron loss. The stability of synchronous motor operation is studied by applying the Nyquist stability criterion to the linearized equations which describe the behavior of the motor as the motor loads perturb about a steady-state operating point. This investigation reveals that, in some cases, the stable region of the motor is delineated from the results of a computer simulation. With a view to reducing harmonic loss and improving torque pulsation from harmonic components, a very poweful pulse amplitude modulation (PAM) method using an 16-bit microcomputer has been developed. This method has the advantages of simplicity of control algorithms and requires small memory space for storing thyristor trigger angles for a three-phase PAM inverter. The method can be used for smooth control of both modulation depth and frequency over a wide range.

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Analysis on electromagnetic characteristics of thrust/levitation system using linear switched reluctance motor and electromagnet according to design parameters (직선형 스위치드 릴럭턴스 전동기와 전자석 추진 부상 시스템의 설계 변수에 따른 전자기 특성해석)

  • Jang, Seok-Myeong;Choi, Ji-Hwan;Park, Ji-Hoon;Sung, So-Young
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.802_803
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    • 2009
  • This paper deals with extraction of design parameters of Linear Switched Reluctance Motor (LSRM) and electromagnet based on force calculation using space harmonic analysis and 2D Finite Element Method (FEM) measurement. We introduce the design method employing FEM and parameter estimation method and a characteristics of LSRM according to variation of parameter.

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Conformal Mapping for Cogging Torque computation in IPM motor (등각 사상법을 이용한 매입형 영구자석 전동기의 코깅토크 해석)

  • Fang, Liang;Kwon, Soon-O;Jung, Jae-Woo;Hong, Jung-Pyo;Ha, Kyung-Ho
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1204-1206
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    • 2005
  • This paper deals with magnetic field analysis and computation of cogging torque in IPM motor with an analytical method, which is based on the Conformal Mapping technique. The magnetic field is analyzed by solving space harmonic field analysis due to inserted PM magnetizing distribution. Conformal Mapping method is then used for considering the slot opening effect and rotor saliency effect on the air-gap field magnetic distribution. Then, by integrating the field over the stator surface, cogging torque is calculated. The validity of the proposed analytical method is confirmed by comparing the results with 2-D FEA results.

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Hybridal Method for the Prediction of Wave Instabilities Inherent in High Energy-Density Combustors (1): Modeling of Nonlinear Cavity Acoustics and its Evolution

  • Lee, Gil-Yong;Yoon, Woong-Sup
    • International Journal of Aeronautical and Space Sciences
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    • v.7 no.2
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    • pp.26-32
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    • 2006
  • This paper targets a direct and quantitative prediction of characteristics of unstable waves in a combustion chamber, which employs the governing equations derived in terms of amplification factors of flow variables. A freshly formulated nonlinear acoustic equation is obtained and the analysis of unsteady waves in a rocket engine is attempted. In the present formalism, perturbation method decomposes the variables into time-averaged part that can be obtained easily and accurately and time-varying part which is assumed to be harmonic. Excluding the use of conventional spatially sinusoidal eigenfunctions, a direct numerical solution of wave equation replaces the initial spatial distribution of standing waves and forms the nonlinear space-averaged terms. Amplification factor is also calculated independently by the time rate of changes of fluctuating variables, and is no longer an explicit function for compulsory representation. Employing only the numerical computation, major assumptions inevitably inherent, and in erroneous manner, in up to date analytical methods could be avoided. With two definitions of amplification factor, 1-D stable wave and 3-D unstable wave are examined, and clearly demonstrated the potentiality of a suggested theoretical-numerical method of combustion instability.

Nonlinear Simulation of Flutter Flight Test with the Forced Harmonic Motion of Control Surfaces (조종면 강제 조화운동을 고려한 비선형 플러터 비행시험 모사)

  • Yoo, Jae-Han;Kim, Dong-Hyun;Kwon, Hyuk-Jun;Lee, In;Kim, Young-Ik;Lee, Hee-Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.6
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    • pp.92-100
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    • 2002
  • In this study, transonic/supersonic nonlinear flutter analysis system of a complete aircraft including forced harmonic motion pf control surfaces has been effectively developed using the modified transonic small disturbance (TSD) equation. To consider the nonlinear effects, the coupled time marching method (CTM) combining computational structural dynamics (CFD) has been directly applied for aeroelastic computations. The grid system for a complex full aircraft configuration is effectively generated by the developed inhouse code. Intransonic and supersonic flight regimes, the characteristics of static and dynamic aeroelastic effect has been investigated for a complete aircraft model. Also, nonlinear flutter flight simulations for the forced harmonic motion of control surfaces are practically presented in detail.

Characteristics Analysis of Radially Magnetized Tubular type Magnetic Coupling (반경 방향으로 자화된 Tubular 타입 자기 커플링의 특성 해석)

  • Kim, Chang-Woo;Jung, Kyoung-Hun;Choi, Jang-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.11
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    • pp.1551-1557
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    • 2015
  • Magnetic coupling is used where required high reliability. because magnetic coupling's durability is stronger than mechanical coupling's durability. This paper shows the characteristics of radially magnetized tubular type magnetic coupling by using Analytical method such as space harmonic method. Analytical method was used, to find force characteristics. First, on the basis of the magnetic vector potential and two-dimensional(2-D) polar-coordinate system, the magnetic field solutions of the radially magnetized permanent magnet are obtained. And we obtain the analytical solutions for the flux density produced by permanent magnet. Finally, we can calculate the force by using the Maxwell stress tensor. And then, Finite element method(FEM) is used to validate force characteristics.