• Title, Summary, Keyword: armature reaction field

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Improved Method for Calculating Armature-Reaction Field of Surface-Mounted Permanent Magnet Machines Accounting for Opening Slots

  • Zhou, Yu;Li, Huaishu;Wang, Qingyu;Xue, Zhiqiang;Cao, Qing;Zhou, Shi
    • Journal of Electrical Engineering and Technology
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    • v.10 no.4
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    • pp.1674-1681
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    • 2015
  • This paper presented an improved analytical method for calculating armature-reaction field in the surface-mounted permanent magnet machines accounting for opening slots. The analytical model is divided into two types of subdomains. The current of the armature is centralized in the center of the slots. The field solution of each subdomain is obtained by applying the interface and boundary conditions of the model. Two 30-pole/36-slot prototype machines with different slot-opening width are used for validation. The FE (finite element) results confirm the validity of the analytical results with the proposed model. The investigation shows that the wider the slot-opening width is, the smaller the peak value of radial and circumferential components of flux density, and the analytical armature-reaction field produced by centralized current in the slots is similar with the armature-reaction field produced by distributed current in the slots in the FE.

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.

Study on the Recoil Operation of the Servomotor with PM Poles (PM형 제어용 Servo전동기의 Recoil동작에 관한 연구)

  • Se Hoon Chang
    • 전기의세계
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    • v.21 no.4
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    • pp.15-21
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    • 1972
  • For the conventional DC machine, the armature MMF is negligible compared with field MMF except when the machine is under heavy load or transient conditions. During the motor starting or reversal, the transient armature current and corresponding MMF effect the flux density of each pole in the machine magnetic circuit. However, the circuit flux density is restored to normal values by the field winding MMF after the transient armature current dies in an electromagnetic DC motor. Permanent magnet servomotor have no field windings about the circuit poles to restore circuit flux density through the demagnetized part of each pole after the transient armature MMF dies, and portions of the magnetic circuit stay permanently demagnetized. Thus the problem of stabilizing a magnet pole piece under the influence of the transient armature current need attentions. This work present the recoil operation of the servomotor with PM poles in conjunctions with the influence of the armature reaction effect. The development of an analytical and quantatative study is presented for predicting the regime of the recoil operation under this condition.

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A study on Field-Weakening Control for Permanent Magnet Synchronous Motor (영구자석형 동기전동기의 약계자제어에 관한 연구)

  • Lee, Cheol-Gyun;Won, Jong-Soo
    • Proceedings of the KIEE Conference
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    • pp.5-9
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    • 1990
  • A permanent magnet synchronous motor(PMSM) differs from an ordinary synchronous motor in that the former has no field winding and the field flux can not be controlled by field current. A field-weakening control of PMSM utilizing the demagnetization due to d-axis armature reaction is equivalent to reducing the field current. In this paper, the armature resistance is considered for the optimum field-weakening control.

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Dynamic Characteristics of Moving Coil Linear Oscillatory Actuator Considering the Variable Inductance and Push/pull Effects (가동차 위치에 따른 인덕턴스 변화와 Push/Pull 효과를 고려한 가동코일형 LOA의 동특성)

  • Jeong, Sang-Sub;Jang, Seok-Myeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.7
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    • pp.307-314
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    • 2001
  • A moving coil linear oscillatory actuator is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The variation of mover position and the consequent changes of coil flux path affect the coil inductance, because coil flux leaks at the open region of LOA stator. The interaction between permanent magnet and armature field is to shift the airgap flux density variation due to the magnet alone by a certain amount. The unbalanced reciprocation force due to armature reaction field decreases the advantage of moving coil LOA, such as a high degree of linearity and controllability in the force ad motion control. This paper firstly describes the coil inductance, the deviation of flux density, and the unbalanced reciprocation force, which are derived form the permeance model of LOA. Secondly, the analytical method are verified using the 2D finite element method and tests. Finally, the dynamic simulation algorithm taking the armature reaction effect and variable inductance into account, is proposed and confirmed through the experiment.

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Eddy Current Loss Analysis of Slotless Double-sided Cored Type Permanent Magnet Generator by using Analytical Method (해석적 방법을 이용한 슬롯리스 양측식 코어드 타입 영구자석 발전기의 와전류 손실 해석)

  • Jang, Gang-Hyeon;Jung, Kyoung-Hun;Hong, Keyyong;Kim, Kyong-Hwan;Choi, Jang-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.10
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    • pp.1639-1647
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    • 2016
  • This paper deals with eddy current loss analysis of Slotless Double sided Cored type permanent magnet linear generator by using analytical method, space harmonic method. In order to calculate eddy current, this paper derives analytical solution by the Maxwell equation, magnetic vector potential, Faraday's law and a two-dimensional(2-D) cartesian coordinate system. First, we derived the armature reaction field distribution produced by armature wingding current. Second, by using derived armature reaction field solution, the analytical solution for eddy current density distribution are also obtained. Finally, the analytical solution for eddy current loss induced in permanent magnets(PMs) are derived by using equivalent, electrical resistance calculated from PMs volume and eddy current density distribution solution. The analytical result from space harmonic method are validated extensively by comparing with finite element method(FEM).

Comparative Study of Armature Reaction Field Analysis for Tubular Linear Machine with Axially Magnetized Single-sided and Double-sided Permanent Magnet Based on Analytical Field Calculations

  • Shin, Kyung-Hun;Park, Min-Gyu;Cho, Han-Wook;Choi, Jang-Young
    • Journal of Magnetics
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    • v.20 no.1
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    • pp.79-85
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    • 2015
  • This paper presents a comparative study of a Tubular Linear Machine (TLM) with an Axially Magnetized Single-sided Permanent Magnet (AMSPM) and an Axially Magnetized Double-sided Permanent Magnet (AMDPM) based on analytical field calculations. Using a two-dimensional (2-D) polar coordinate system and a magnetic vector potential, analytical solutions for the flux density produced by the stator windings are derived. This technique is significant for the design and control implementation of electromagnetic machines. The field solution is obtained by solving Maxwell's equations in the simplified boundary value problem consisting of the air gap and coil. These analytical solutions are then used to estimate the self and mutual inductances. Two different types of machine are used to verify the validity of these model simplifications, and the analytical results are compared to results obtained using the finite element method (FEM) and experimental measurement.

Magnetic Field Distribution in Brushless Permanent Magnet do Motors, Part II : Armature-Reaction Field (BLDC 전동기의 자계분포 Part II : 전기자 반작용 자계)

  • Jang, Seok-Myeong;Choi, Jang-Young;Cho, Han-Wook;Yang, Hyun-Sup;Lee, Sung-Ho
    • Proceedings of the KIEE Conference
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    • pp.37-39
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    • 2004
  • This paper deals with the prediction of armature reaction field produced by 3-phase stator windings whose current waveform contains significant harmonics. On the basis of 2-d analytical technics, we derived governing equation and predicted magnetic field distribution according to rotor position. The results of predictions from the analysis are compared with corresponding FE (finite element) analyses.

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Analytical and Experimental Study for Electromagnetic Performances of a Tubular Linear Machine with Axially Magnetized Single-sided Permanent Magnets

  • Shin, Kyung-Hun;Jeong, Kyoung-Hun;Choi, Jang-Young;Hong, Keyyong;Kim, Kyong-Hwan
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.432-438
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    • 2015
  • This paper presents an electromagnetic analysis of a tubular linear machine with axially magnetized permanent magnets using improved analytical techniques. Based on the magnetic vector potential and a two-dimensional polar-coordinate system, the magnetic field and armature reaction field can be derived. Using these, equivalent circuit parameters, such as the electromotive force and inductance, can be obtained analytically. Finally, the generating characteristics are derived with the equivalent circuit method. In this study, the finite element method was employed to provide a comparative evaluation, and experiments were conducted to validate the results of the analytical analysis.

Reduction of Armature Reaction for Moving Coil Linear Oscillatory Actuator (가동코일형 LOA에서의 전기자 반작용 저감법)

  • Jang, S.M.;Jeong, S.S.;Lee, S.H.;Yun, I.K.
    • Proceedings of the KIEE Conference
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    • pp.580-582
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    • 2001
  • In moving coil LOA, the variation of mover position and the consequent changes of coil flux path affect the coil inductance because of unbalanced magnetic circuit. Furthermore, the armature field shifts and distorts the airgap flux density distribution due to the magnet alone by a certain amount, which cause the unbalanced reciprocating force. In this paper, we propose the reduction method of armature reaction and coil inductance. The proposed LOA has the shorted ring the saturated core, the double coil, and Halbach array.

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