• 한국정밀공학회지
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• 제17권3호
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• pp.158-164
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• 2000

In recent year, desire and request fer micro automation are growing rapidly covering the whole range of the industry. This has been caused mainly by request of more accurate manufacturing process due to a higher density of integrated circuits in semiconductor industry. This paper presents a six d.o.f fine motion stage using magnetic levitation technique, which is one of actuating techniques that have the potential for achieving such a micro motion. There is no limit in motion resolution theoretically that the magnetically levitated part over a fixed stator can realize. In addition, it Is possible to manipulate the position and the force of the moving part at the same time. Then, the magnetic levitation technique is chosen into the actuating method. However, we discuss issues of design, kinematics, dynamics, and control of the proposed system. And a few experimental results fur step input are given.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.433-438
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• 2003

The recent operating trains including the high speed train are mostly moving system on the rail and system use the mechanical propulsion force to drive the gear and wheel by the traction motor. Advanced countries are interested in Magnetic Levitation Vehicle and they have been studying about it continuously. Thus this paper is analyzed the feature of analysis the feature for Linear Induction Motor as the propulsion equipment of Magnetic Levitation Vehicle. And the Magnetic Levitation Vehicle is being developed for the transportation system of next generation using the Finite Element Method

• 대한전기학회논문지
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• 제41권1호
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• pp.18-23
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• 1992

Magnet core and rail of a magnetically levitated vehicle are usually made of highly conductive materials. Accordingly, eddy currents are induced in those members. Eddy currents often lead to a decrement of levitation and guidance force. This paper has calculated the decrement of both forces due to eddy current generated by magnet's vertical and lateral motion. U-shaped electromagnet and rail were chosen as amodel of 2D finite element analysis. Calculated results proved that both forces dropped significantly at high speed. Consequently, effects of eddy current should be considered in designing the magnet and control system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.415-420
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• 2006

This paper introduces a new self-bearing motor which combines a homopolar step motor and a passive magnetic bearing. Compared with conventional self-bearing motors which are mostly based on the theory of active magnetic bearings and therefore have some difficulties in design of the complicated flux distribution and control of the levitation force and the torque independently, the proposed self-bearing motor has a very simple and novel structure and operating principle. for the levitation, it works just like passive magnetic bearings which use the repulsive force between permanent magnets. On the other hand, its rotation principle is quite similar to that of a conventional homopolar step motor. In this paper, we introduce the basic structure and the operating principle in detail, and show some results of FEM analysis to predict the performance of the proposed self-bearing motor and further, to get the optimal design parameters.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권12호
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• pp.592-600
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• 2005

In this paper, a low loss magnetic levitation(Maglev) system is suggested and tested. The suggested Maglev system includes four hybrid magnets which consist of permanent magnet and coil. In the steady state, the levitated module system can be supported by attraction force generated by permanent magnet. The coil current controls only dynamic loads due to external disturbances. The module systems are designed by using finite element method(FEM) software tools such as MAXWELL and ANSYS. Also, digital control systems are designed to keep the magnet airgap at a constant value. The control systems include a VME(versa module europa)-based CPU(central processing unit) board, AD(analog to digital) board, PWM(pulse width modulation) board, 4-quadrant chopper, and sensors. In order to estimate the vertical velocity of the magnet, we use second order state observer with acceleration and gap signals as input and output signals, respectively. The characteristics of the suggested low loss Maglev system are demonstrated by experimental results showing coil current of 0A in the steady state of 3m airgap and performance specifications are satisfied for reference gap and force disturbance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1940-1942
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• 2001

Magnetic Levitation System(MLS) levitates a steel ball to the desired position in the gravity field using electromagnetic force. MLS consists of light sensor to measure the position of steel ball and an electromagnet to control the position of the ball, that composes a feedback control system. This work does not use a steel ball with constant mass but variable mass steel balls as magnetic levitation targets. Differential equation of electric circuit for electromagnet and motion equation of the movement of steel ball are derived for modeling nonlinear system, that will be linearized at the nominal operating point. We propose a digital control that can levitate a steel ball of which weight is not known for ED-4810 system. Algorithm for estimating ball weight and feedback control are implemented in digital scheme under pentium PC equiped with A/D and D/A converter, ACL-8112, using C-language. Simulation and experimental results are given to show the usefulness of the proposed controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.289-291
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• 1996

Linear induction motor(LIM) is widely used to drive magnetic levitation train. To drive LIM, different control method compared with conventional rotary type machine is needed. Since vertical force is generated inherently and it effects on the levitation system, vertical force should be kept constant for stable levitation. To keep vertical force constant, slip frequency should be kept constant. Once slip frequency is kept constant, tractive force can be controlled by adjusting motor currents. In this paper, control methods used so far arc analyzed with some experimental results and decoupling control algorithm is proposed to control tractive and vertical force separately. Control algorithm is verified through simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1049-1050
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• 2007

In this paper, an electromagnet which is used in maglev(magnetic levitation) clean lift is designed and described. The electromagnet is firstly designed by using FEM(finite element method) tool and the simulation results are presented. The nominal airgap is 5mm and the nominal current is 2A. Also, the nominal magnetic force is 200N. From the results, we can get the electromagnet as an actuator used in maglev(magnetic levitation) clean lift for LCD process.

• 한국정밀공학회지
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• 제15권10호
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• pp.165-171
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• 1998

An axial electromagnetic levitation system using attractive force is a highly nonlinear system due to the nonlinearity of materials, variable air gap and flux density. To control the levitating system with large air gap, a conventional PID control based on the linear model is not satisfactory to obtain the desired performance and the position tracking control of the sinusoidal motion by simulation results. Thus, sliding mode control(SMC) based on the input-output linearization is suggested and evaluated by simulation and experimental approaches. Usefulness of the SMC to this system is conformed experimentally. If the expected variation of added mass can be included in the gain conditions and the model, the position control performance of the electromagnetic levitation system with large air gap will be improved with robustness.

• 한국산학기술학회논문지
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• 제22권1호
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• pp.792-800
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• 2021

본 논문은 Halbach 자석 배열을 사용하여 새로운 구조의 선형 능동자기 베어링 개발을 제시하고자 하였다. 선형 능동자기 베어링은 자석 간 발생하는 자중 보상 능력과 코일에 전류를 인가함으로서 발생하는 동적 힘을 이용하여 반도체 장비, 가공 장비 등 다양한 산업분야에서 적용되고 있다. 기존의 선형 능동자기 베어링은 크기에 비해 동적 힘이 낮은 문제점이 있다. 따라서 본 논문에서는 기존 보다 높은 동적 힘을 발휘하는 선형 능동자기 베어링을 개발하기 위해 시뮬레이션을 통해 기존 구조를 분석하고 새로운 구조를 제안하였다. 제안된 새로운 구조의 선형 능동 자기베어링을 최적화하기 위해서 모델링 및 최적 설계를 수행하였다. Sequential Quadratic Programming을 사용하여 제안된 선형 능동자기 베어링의 기하학적 설계 변수에 대해 최적의 설계가 수행되었으며, 최적설계 된 선형 능동자기 베어링의 설계성능은 정적 힘 45.063 N, 로렌츠 힘 상수 19.543 N/A 로 기존보다 높은 동적 힘을 발휘하는 것이 확인되었다.