• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.47-52
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• 2007

This paper presents characteristics analysis of persistent current switch(PCS) system on a small scale by using YBCO coated conductor(CC). A high temperature superconductor(HTS) PCS system mainly consists of a PCS, a HTS magnet load and a magnet power supply(MPS). To design the optimal heater triggering switch. the three-dimensional heat conduction model was analyzed by finite element method(FEM). The electrical equivalent model considering the n-value of CC was applied to analyze current decay during persistent current mode. In the experiment and simulation, the heater was applied with a current of 0.43A and the current was ramped up to 10A and 20A with 0.2A/s. Finally, experimental results of the HTS PCS system have been compared with the theoretical results. It has been concluded that flux creep can not influence the results because the operating current was 40% of critical current and optimal sequential operation of the PCS system is indispensable to enhance its performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1159_1160
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• 2009

본 논문에서는 초고속 자기부상열차의 유력한 후보가 될 수 있는 초전도 반발식 자기부상의 특성을 연구하기 위한 반발력을 3차원 유한요소 자기 해석을 통하여 계산하고 분석하였다. 본 해석의 결과에 따르면 움직이는 부분이 없는 정지형 시험기는 반발식 자기부상시험기로써 적용될 수 있다.

• Nuclear Engineering and Technology
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• 제40권6호
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• pp.467-476
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• 2008

To keep the superconducting (SC) magnet coils of KSTAR at proper operating conditions, not only the coils but also other cold components, such as thermal shields (TS), magnet structures, SC bus-lines (BL), and current leads (CL) must be maintained at their respective cryogenic temperatures. A helium refrigeration system (RRS) with an exergetic equivalent cooling power of 9 kW at 4.5 K without liquid nitrogen ($LN_2$) pre-cooling has been manufactured and installed. The main components of the KST AR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The process helium is compressed from 1 bar to 22 bar passing through the WCS and is supplied to cryogenic devices. The main components of cryogenic devices are consist of cold box (C/B) and distribution box (D/B). The C/B cool-down and make the various cryogenic helium for the KSTAR Tokamak and the various cryogenic helium is distributed by the D/B as per the KSTAR requirement. In this proceeding, we will present the commissioning results of the KSTAR HRS. Circuits which can simulate the thermal loads and pressure drops corresponding to the cooling channels of each cold component of KSTAR have been integrated into the helium distribution system of the HRS. Using those circuits, the performance and the capability of the HRS, to fulfill the mission of establishing the appropriate operating condition for the KSTAR SC magnet coils, have been successfully demonstrated.

• 조명전기설비학회논문지
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• 제24권6호
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• pp.123-130
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• 2010

일반적으로 매입형 영구자석 동기전동기(IPMSM)의 초기설계는 자기등가회로법을 이용한다. IPMSM의 경우 회전자에 매입된 영구자석 배치의 자유도가 매우 높지만 자기등가회로법은 영구자석의 배치를 고려하기 어렵다. 따라서 설계변수와 응답에 대한 관측 자료로부터 해석적인 근사모형을 제시함으로써 실질적인 목적함수를 쉽게 만들 수 있는 반응표면법(RSM)을 활용하였으며 조건에 따른 관계를 예측하기 위해 필요한 실험 데이터는 유한요소법을 이용하였다. 본 논문에서는 IPMSM의 고 토크와 저 토크 리플을 위한 반응 표면법을 이용한 매입형 영구자석 동기전동기의 이층 영구자석 회전자 구조 다목적 최적 설계를 제안한다.

• 전기학회논문지
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• 제58권10호
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• pp.1942-1946
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• 2009

This paper presents a shape design process of Claw-Poles Stepping Motor(CPSM) using Modified Magnetic Equivalent Circuit Method(MMEC). Because this motor is adopted on low power devices, the motor size is a very small type. But it have a very strong permanent magnet. So magnetic saturation effect happens on yoke teeth of CPSM. Also this magnetic saturation effect causes more leakage flux component between yoke tooth have another pole. In this motor type, it is essential to design a shape of yoke teeth for avoiding the magnetic saturation effect and the leakage flux. In this paper, MMEC including the magnetic saturation effect and the leakage flux component was used for design process. Comparing with data calculated by using the MMEC and results analyzed by 3-D FEM, it could be stated that the design process with MMEC was reasonable. Finally, the model has the optimized shape of yoke teeth was compared with a conventional model for no-load Back EMF and torque at steady-state operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.753-755
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• 2002

This paper presents the characteristic analysis by changing the shape and position of auxiliary pole core for Automotive stater motor. The brush contact resistance and mechanical loss calculated from the experimental data are used in characteristic analysis. The Finite Element Analysis Method(FEM) and 3D Equivalent Magnet Circuit Network(EMCN) are used for analysis. The validity of the proposed methods are verified by comparison of analysis results and experimental ones.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.22-24
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• 1996

The problem of the heat flow in the Surface Permanent Magnet Synchronous Motor(SPMSM) at various load condition is solved by use of the thermal equivalent network method. For the correction of the, design parameters of SPMSM and for the exact analysis of several characteristics, the iterative method combining the characteristics analysis and the thermal analysis. Then the analyzed results and the measured data are compared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.879_880
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• 2009

this paper studies the influence of permanent magnet on the vibration of synchronous motor two PM motors with NdFeB and Ferrite magents which have same Back-EMF and output power have been desined. First, the dynamic simulation is performed with these two motors' parameters. The current waveforms can be evaluated. And then based on the equivalent magnetization current principle, the magnetic force density and force including the tangential and radial direction components can be calculated. According to the relationship between the vibration and radial force, the vibration of these two motors can be predicted. This result will give meaningful advice to the motor design.

• 전기학회논문지
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• 제61권4호
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• pp.555-566
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• 2012

This paper presents a thermal analysis of an interior PM synchronous machine with concentrated winding for electric vehicle. The conventional thermal equivalent network model has been used for a long time for calculation of the temperature rises in electrical machines. In spite of being popular, this method can not be applied correctly for elements with complicated cooling structure like liquid cooled housing. To overcome this drawbacks, in this paper, a hybrid thermal model using the result of CFD analysis partly. Using this method, to improve a thermal performance of PMSM with concentrated winding, the effects of two design parameters are analysed. Finally, the accuracy of this model has been verified by experiments for the developed 21kW motor.

• 조명전기설비학회논문지
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• 제20권8호
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• pp.63-70
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• 2006

본 논문은 철도에 사용되는 전차선로-집전계 주행시험기용 고속 리니어 추진시스템의 설계를 제안한다. 여러 가지 다양한 추진시스템 중에서 요구사양을 만족하며 짧은 구간에 높은 가속력을 제공할 수 있는 영구자석형 선형동기전동기를 선택하였다. 설계는 전동기의 특성식과 등가자기회로법을 이용하여 수행하였으며, 유한요소법을 이용하여 이를 검증하였다. 또한 실험계획법을 통하여 추진시스템의 성능에 주요한 영향을 미치는 주 설계인자의 분석을 수행하였다.