• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권3호
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• pp.135-142
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• 2004

In this paper, the magnetic circuit characteristics and the current/torque analysis of a Spoke Type permanent magnet motor have been researched, compared with the SPM Type motor. In the magnetic circuit analysis, the characteristic of air-gap flux density has been analyzed according to the variation of the number of pole and the ratio of magnet height to arc length using finite element method and circuit equations. Moreover, the electromagnetic and the reluctance torque have been analyzed by the current profile, which is obtained from the variation of turn-on angle, and these informative data has been utilized for the overall characteristics of the Spoke Type BLDC motor.

• 한국정밀공학회지
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• 제21권2호
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• pp.83-91
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• 2004

This paper illustrates the feasibility and the effectiveness of the disturbance feedforward compensation control proposed in the previous paper. The compensator is designed experimentally by means of the Multiple Filtered-x Least Mean Square algorithm. A 2-DOF active magnetic bearing system subject to base motion is built and the compensation control is applied. The experimental results demonstrate that the compensation control reduces the air-gap responses within 10$%$ of those by the feedback control alone without increasing the control inputs.

• 한국자기학회지
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• 제4권2호
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• pp.106-113
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• 1994

초전도 반발식 자기부상열차의 동특성을 해석하기 위하여 외력에 의하여 대차가 기울어진 경우에 차량에 가해지는 전자력을 계산하였다. 집중부하방식의 열차에 있어서 크게 나타나는 단부효과 를 고려하기 위하여 공극자속의 형태에 대한 가정없이 자속분포를 계산하였으며, 대차의 옆질(roll), 뒷질(pitch) 및 편주(yaw)시의 전자력특성과 복원토오크를 검토하였다. 6개의 초전도자석이 탑재된 대 차가 차량의 양쪽에 설치된 열차에 대해서 계산한 결과, 토오크의 방향은 차량을 안정하게 하는 방향 으로 나타나서 본 자기부상시스템은 기본적으로 안정한 시스템임을 보여주고 있다.

• 한국초전도ㆍ저온공학회논문지
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• 제1권2호
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• pp.30-36
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• 1999

Superconductors are dissipative when exposed to time-varying magnetic fields. To analyze the AC characteristics of a superconductor, one usually needs to know magnetization curves of it. Good magnetization curves can be obtained only in homogeneous magnetic filed. In This paper, we report the setup and test results of a magnetization measurement system, which consists mainly of frequency-variable power supply and homeogenous magnet with 7-cm long air gap. Special emphasis are foused on the design and fabrication of the magnet, which aims to give background magnetic fields, and on the overall characteristics of the system.

• 전기의세계
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• 제30권4호
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• pp.219-226
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• 1981

The magnetic field distribution in saturable iron part of electromagnetic energy conversion divices is defined by the nonlinear quasi-Poisson enquation that is described the electromagnetic field characteristics and satisfied the natural boundary condition. The solution of this equation is obtained by minimizing an energy functional by means of trial function that defined in triangular subregion of two-dimensional field region. As a result, the accuracy of the machine design is increased by use of its solution. In this respect, this study is developed the basic theory to analyze the magnetic flux distribution in saturable iron part and air gap of induction motor that its secondary part is short circuit by the variational principle, the minimized theory of energy functional, the application of F.E.M., and treatment of computer. As theoritical data compared with the practics, the validity of the theory in this study is supported by experimental findings.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권11호
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• pp.597-603
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• 1999

Due to its simple construction, operation steadiness and low cost, claw pole step motor is widely used for OA machine and automobile. This paper deals with analysis fo claw pole motor, especially eyeing to dynamic characteristics. To analyze dynamic characteristics of claw pole step motor, torque development in each angular step of rotor are surveyed and torque equation is drived using permeance method. To adopt the airgap MMF, the magnetic equivalent circuit of the motor is introduced. On the base of the magnetic equivalent circuit, the air gap flux equation is derived. To get a optimum design of the motor, the torque characteristic is studied in variation of coil data and remanence value of permanent magnetic material.

• 전기학회논문지
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• 제60권3호
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• pp.531-537
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• 2011

This paper proposes a finite element method (FEM)-based model of an interior permanent magnet (IPM) type BLDC motor having stator inter-turn faults. For more realistic simulation studies, the magnetic non-linearity is also considered in proposed model. And the simulation data are verified through experiment. By integrating the developed model with a current-controlled voltage source inverter (CCVSI) model, the characteristics of an inter-turn fault operated by six-switched inverter are investigated considering the speed control. And the circulating current, which is induced by magnetic linkage flux originated from PM, was analyzed from the view point of distortion of air-gap magnetic flux distribution caused deterioration of their torque.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1029-1031
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• 2005

A magnetic position sensor is a apparatus that detect the rotating position by measuring the value of the flux density of the rotating position. In this paper, the magnetization system of the permanent magnet in the magnetic position sensor which detects the rotating position was designed. The permanent magnet was magnetized for the flux density into the hole element to be sinusoidal distribution according to the rotating position. To make the sinusoidal distribution of flux density, the magnetization values according to the position in permanent magnet were varied by adjusting the air gap between the pole of the magnetization fixture and the surface of the permanent magnet.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.780-785
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• 2001

A moving-magnet type pickup actuator is proposed, which has the back-yoke to improve th sensitivity. Through the magnetic path analysis, we can find that the flux density is increased i the air gap by the pole assignment of magnet and the adding of back-yoke can reduce the flu leakage and induce 40％ up of flux density. Experimental results show that the sensitivity i improved in the tracking direction, however, the improvement doesn't occur in the focusing direction. Finally, the compensation performance is tested in HD-DVD system. And it is verifie that the actuator can compensate the disc tilt of ${\pm}$0.7$^{\circ}$.