• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.171-173
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• 1994

Magnetic wedge is proposed for improving the motor performance and to reduce the ripple of air gap flux. Carter's coefficient plays very important role when the ampere turns or exciting current is calculated. In this paper, we calculate the Carter's coe. by FEM taking into account the magnetic anisotropy of magnetic wedge in simple manner and analyze the effect of the wedge. And we analyze the slot leakage flux according to the wedge property.

• 전기학회논문지
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• 제56권5호
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• pp.860-868
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• 2007

In this paper. design of spoke type BLDC motor which have a characteristics of concentrating fluxes and relatively high reluctance torque among IPM BLDC motors has been researched. To reduce cogging torque and torque ripple. rotor pole shape of optimal design is proposed. To clearly see the effects due to the changed rotor pole shape. magnetic circuit model. 2D FEM and design of experiments (DOE) are used. Then considering these results proper rotor pole shape which have an good effect on air gap flux density and cogging torque. back-emf is designed. Moreover. the validity of proposed model in this paper is also verified by comparison between gained experiment and analysis data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.40-42
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• 2004

In this paper, optimum shape design of permanent magnet in slotted type Permanent Magnet Linear Synchronous Motor(PMLSM) is progressed for minimization of detent force owing to structure of slot-teeth and thrust ripple by harmonic magnetic flux of permanent magnet. The characteristics of thrust and detent force computed by Finite element Analysis are acquired equal effect both skewed basic model and optimum model which is optimization of permanent magnet shape.

• 한국수소및신에너지학회논문집
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• 제18권2호
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• pp.216-223
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• 2007

The present carbon-based energy system will not last long due to its environmental and economical drawbacks. Hydrogen energy attracts more attention recently and seems to have large ripple effect on economy providing its technical, environmental and economical problems are solved. This paper analyses the situation changed from fossil to non-fossil energy system and the R&D policies of advanced countries by reviewing the world energy status and the energy policy of foreign countries. Finally, the R&D strategy of hydrogen energy technology was developed through analyzing the present states of energy research policy and programs of major countries.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.308-309
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• 2018

Construction automation is needed to improve construction productivity. 3D printing is a key technology of the 4th industrial revolution, and when applied to the construction field, the ripple effect is very large. In this paper, we propose a 3D printing method that can predict the 3D printing process and estimate the construction duration for each process. Through literature review and expert consultation, eight 3D printing activities for structure work were derived. Construction duration and cost estimation for each activity will be needed in the future research.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.767-768
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• 2006

Cogging torque is produced in a permanent magnet machine by the magnetic attraction between the rotor-mounted permanent magnets and the stator. It is an undesired effect that contributes to the machines' output ripple, vibration, and noise. This paper presents the stator design for reducing cogging torque in the BLDC motor by using the DOE(Design of Experiments). The cogging torque is computed by using a two-dimensional finite element analysis.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 추계학술대회 및 정기총회
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• pp.77-83
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• 2005

기후변화협약에 의해 탄소세가 부과될 경우 한국의 에너지 집약 산업에 어떠한 영향을 미치며 그에 대한 대응방안이 어떻게 마련되어야 하는지에 대한 관심이 증대되고 있다. 이에 본 연구에서는 탄소세가 부과됨으로 인하여 에너지 다소비 업종인 시멘트산업의 각 에너지원별 사용량에 미치는 파급효과를 시스템 다이내믹스 방법론에 의한 시뮬레이션 모델을 이용하여 분석하였다. 시뮬레이션 모델은 환경모듈, 경제모듈, 에너지모듈로 구성하였고 모델의 예측력 검증을 위해 의태분석을 수행하였다. BAU 시나리오와 탄소세 부과 시나리오를 설정하여 각 시나리오의 총수요의 예측치, 이산화탄소 배출량의 추이, 에너지원의 사용변화를 분석하였다. 본 연구는 향후 기후변화협약의 부담이 큰 에너지 집약산업에 있어서 에너지원의 사용 및 수요를 예측하고 이를 평가하기 위한 지침을 제시할 수 있을 것으로 기대된다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권10호
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• pp.530-536
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• 1999

This paper investigates effects of segmented poles on exciting forces such as cogging torque, BEMF, phase current, torque ripple and local forces. Cogging torque, BEMF and local force are determined by FEM analysis and phase current is calculated using voltage equations after determining BEMF and phase inductance. Effective dead zones at pole separations result in wider than the physical dead zones due to leakage field during magnetization. Due to the existence of dead zones, there exist additional exciting harmonics of the cogging torque which play adverse effect on vibration and noise performance. The magnitude of BEMF is decreased and the waveforms are also distorted depending on dead zone positions. Segmented poles inevitably cause uneven magnetic field distribution at pole separations which introduces additional harmonics of exciting forces which are detrimental to structural to structural resonances. They also decrease motor efficiency by reducing effective phase BEMF.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.779-781
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• 1987

In phase controlled rectifier(PCR), harmonica are changed according to the variation of a firing angle. These harmonics are supplied with the input of the inverter. And then, inverter output comes about the harmonics combined with the switching frequency of the inverter. Hence the efficiency of the induction motor ia decreased by the harmonic of the inverter output. In this paper, it analyzed about an effect of these harmonics ia analyzed by a computer simulation. The total harmonic distortion (THD) in the case of PCR containing the ripple was considerably larger than THO of the DC source. Therefore, it was proved that the firing angle variation of PCR had to be limited.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.791-793
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• 2004

Voltage unbalance is generated by the load and impedance mismatching at the 3-phase 4-wire system of customer load. Voltage unbalance factor can be changed by the voltage amplitude or phase angle, and both. A small voltage unbalance is connected to high current unbalance. If the voltage unbalance is generated at the joint system of 1-phase and 3-phase load, Induction motor due to the current unbalance increase is generated loss, noise and torque ripple. In order to analyze the effect by voltage unbalance, it is necessary to the consideration of amplitude and phase angle. In this paper, We analyzed the effects that induction motor is affected by asymmetric voltage unbalance