• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.137-140
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• 2002

EM(ElectroMagnetic) pump is used for the purpose of transporting liquid sodium coolant with electrical conductivity in the LMR(Liquid Metal Reactor). In the present study, computer program for the pilot annular linear EM pump has been developed for the maximum flowrate with 200 l/min and maximum developing pressure with 3 bar. Firstly, Balance equation is induced by the equivalent circuit method which is commonly employed to analyze linear induction machines and the calculation of the hydraulic pressure drop. Then, design equation is converted to the computer program and optimum pump variables are determined by this code. The code is verified by the comparative analysis with the characteristic of the commercialized pump.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1821-1834
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• 2017

Medium voltage control applications due to obtain better output voltage and reduced electro-magnetic interference multi level inverter is used. In closed loop control with inverter, the PI controller does not operate satisfactorily when the operating point changes. This paper presents the performance of Co-Efficient diagram PI controller based indirect vector controlled induction motor drive fed from three-level inverter under different operating conditions (dynamic and steady state). The proposed Co-Efficient diagram PI controller based three level inverter significantly reduces the torque ripple compared to that of conventional PI controller. The performance of the indirect vector controlled induction motor drive has been simulated at different operating conditions. For three-level inverter control, a simplified space vector modulation technique is implemented, which reduces the coordinate transformations complications in the algorithms. The performance parameters, torque ripple contents and THD of induction motor drive with three-level inverter is compared under different operating conditions using CDM-PI and conventional PI controllers.

• 전력전자학회논문지
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• 제8권4호
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• pp.351-358
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• 2003

본 논문에서는 IGBT PWM 인버터 구동 유도전동기 고정자 권선에서의 스위칭 써지전압 분포특성을 분석하였다. 고정자 권선의 턴 및 코일간의 전압분포를 해석하기 위하여 케이블을 포함한 유도전동기의 등가모델을 제안하고, 유한요소법을 이용하여 고주파 파라메타를 산출하였다 또한, 유도전동기, IGBT PWM 인버터 및 케이블등에 대한 전체 시스템의 EMTP 시뮬레이션을 통하여 인버터 상승시간, 케이블 길이 및 스위칭 주파수 등의 영향에 따른 전압분포를 분석하였다. 380[V], 50[HP] 유도전동기 고정자 권선을 대상으로 한 전압분포 특성실험을 통하여 인버터용 전동기 설치 및 과전압 억제용 필터 설계시의 유용한 자료를 제시하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1610-1615
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• 2007

This paper presents a characteristics of linear induction motor considering airgap variation for railway transit in order to achieve high performance of the vehicle. The operating principle of a LIM(Linear induction motor) is identical to a rotary induction motor. Space-time variant magnetic fields are generated by the primary part across the airgap and induce the electro-motive force(EMF) in the secondary part, a conducting sheet. This EMF generates the eddy currents, which interact with the airgap flux and so produce the thrust force known as Loren's force. Even though the operating principal is exactly same as a rotary motor, the linear motor has a finite length of the primary or secondary parts and it causes static and dynamic end-effect which is the discontinuous airgap flux phenomenon. This end-effect causes the deterioration of the system performance, especially in high-speed operation. Another problem is that construction tolerance restricts the minimum airgap in order to prevent a collision between the primary part and the secondary reaction plate. More over, as the airgap length is getting smaller, the attraction force between the primary part and secondary parts is getting larger dramatically and the attraction force would be another friction against propulsion. Therefore, it is necessary to figure out the characteristics of linear induction motor considering airgap variation in order to achieve high performance of the vehicle. The dynamic model of LIM taking into account end-effects is derived. Then the modified mechanical load equation considering the effect of the attraction and thrust force according to the airgap variation is analyzed. The simulation results are presented to show the effect of the LIM according to the airgap variation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1903-1908
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• 2008

This paper presents a characteristics of linear induction motor considering airgap variation for railway transit in order to achieve high performance of the vehicle. The operating principle of a LIM(Linear induction motor) is identical to a rotary induction motor. Space-time variant magnetic fields are generated by the primary part across the airgap and induce the electro-motive force(EMF) in the secondary part, a conducting sheet. This EMF generates the eddy currents, which interact with the airgap flux and so produce the thrust force known as Loren's force. Even though the operating principal is exactly same as a rotary motor, the linear motor has a finite length of the primary or secondary parts and it causes static and dynamic end-effect which is the discontinuous airgap flux phenomenon. This end-effect causes the deterioration of the system performance, especially in high-speed operation. Another problem is that construction tolerance restricts the minimum airgap in order to prevent a collision between the primary part and the secondary reaction plate. More over, as the airgap length is getting smaller, the attraction force between the primary part and secondary parts is getting larger dramatically and the attraction force would be another friction against propulsion. Therefore, it is necessary to figure out the characteristics of linear induction motor considering airgap variation in order to achieve high performance of the vehicle. The dynamic model of LIM taking into account end-effects is derived. Then the modified mechanical load equation considering the effect of the attraction and thrust force according to the airgap variation is analyzed. The simulation results are presented to show the effect of the LIM according to the airgap variation.

• 한국정밀공학회지
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• 제26권9호
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• pp.72-80
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• 2009

When the magnet wheel rotates over a conducting plate, it generates the traction torque as well as the repulsive force on the conducting plate. Partially-cut traction torque results in the linear force into the tangential direction. To cut the traction torque, the concept of magnetic shield is introduced. The direction change of the linear force is realized varying the shielded area of magnetic field. That is, the tangential direction of non-shielded open area becomes the direction of the linear thrust force. Specially a shape of permanent magnets composing the magnet wheel leads to various pattern of magnetic forces. So, to enlarge the resulting force density and compensate its servo property a few simulations are performed under various conditions such as repeated pattern, pole number, radial width of permanent magnets, including shape of open area. The theoretical model of the magnet wheel is derived using air-gap field analysis of linear induction motor, compared with test result and the sensitivity analysis for its parameter change is performed using common tool; MAXWELL. Using two-axial wheel set-up, the tracking motion is tested for a copper plate with its normal motion constrained and its result is given. In conclusion, it is estimated that the magnet wheel using partial shield can be applied to a noncontact conveyance of the conducting plate.

• 대한의용생체공학회:의공학회지
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• 제16권4호
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• pp.447-456
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• 1995

완전 이식형 인공심장 개발의 일환으로 무선에너지 전송장치를 개발하였다. 본 연구에서는 피하에 이식된 2차 코일과 피부표면에 놓인 1차 코일 간의 자기 유도의 원리에 의한 전기에너지 전송시스템을 개발하였으며, 이식될 소자의 소형화 및 전송효율의 향상을 목표로 하였다. 클래스 E 공진 증폭기를 이용하여 인공심자의 구동에 요구되는 40 Watt 전송시 75% 이상의 전송 효율을 얻었다. 또한 동물 실험을 실시하여, 체내 성능을 검증하였고 체내 이식부의 생체 적합성도 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.846-848
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• 2001

In this paper, electromagnetic fields of a linear induction motor with cage-type secondary are analyzed by the finite element method. Contact resistances between end-bars and secondary conductors are considered in the finite element analysis. The field quantify is a magnetic vector potential transformed into a phasor form. As a result, the sensitivities of a phase current thrust and normal force are presented according to the variation of the contact resistance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.381-384
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• 2001

The combined stirring method to uniform distribution of particle is consisted of two strring force both electro-magnetic stirring generated from induction heating and mechanical stirring with graphite stirrer. PMMC billets were fabricated with the volume fractions ranged from 0% to 20% and particle sizes ranged from 14$\mu\textrm{m}$ to 25$\mu\textrm{m}$. It is important to control the size of primary ${\alpha}$-AI solid particles because it could become the cause of the particle pushing or capture phenomena from the fact that secondary dendrite arm spacing size depends on the cooling rate during the solidification in hypoeutectic AI-Si alloy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.385-388
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• 2001

In part forming process of metal matrix composites, the die casting and squeeze casting process are limited the size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting squeeze casting and compocasting. However, for the thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.