• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권7호
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• pp.299-306
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• 2003

Doubly-Fed Induction Generator(DFIG) is adequate to maximize the energy capture from wind energy, whereby the turbine speed can be adjusted to a speed, at which a rated tip speed ratio be kept. In this paper, a power analysis for DFIG and its characteristics of power flow in grid-connected operation, are dealt with in speed range of super- and sub-synchronous region. In a test of the machine, whereby a doubly excited circuit configuration in stator as well as rotor with back to back PWM inverter have been equipped, a constant input torque is given and in that condition, power new in stator and rotor circuit have been measured and compared with theoretical value. Furthermore, the power factor in stator and rotor circuit have been examined.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.84-86
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• 2018

Active hybrid solid state transformer(AHSST) is newly emerging as a device to maintan the power quality of power distribution. AHSST has a simple structure in which a power electronics device is connected in series to a conventional distribution transformer. The connected power electronics device maintains the constant voltage regardless of the primary grid voltage fluctuation through the secondary voltage control to improve the power quality. It also has a simple structure compare to conventional solid state transformer system and can achieve the same performance with fractionally-rated converter. This paper proposes an multi-level converter based on AHSST system that has a simpler control method and wider voltage control range than the conventional AHSST. The proposed system is verified by simulations.

• Journal of Power Electronics
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• 제15권4호
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• pp.876-885
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• 2015

High frequency alternating current (HFAC) has been widely used in a wide range of power distribution systems (PDS) due to its superior performance. A high frequency AC/DC converter plays the role of converting HFAC voltage to DC voltage. In this paper, a new LCL-T resonant AC/DC converter has been proposed, and an easier control method based on input voltage comparison is presented, without the complicated calculation of the zero-crossing point. Both a low distortion and near-to-unity power factor can be achieved by the proposed resonant converter and control strategy. The operational principle and steady-state analysis are given for the proposed resonant converter. A simulation model and experimental prototype are implemented with an operation frequency of 25kHz and a rated power of 20W. The simulation and experimental results verify the accuracy of the analysis and the excellent performance of the proposed topology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1756-1758
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• 2005

This paper deals with the power conversion and design of permanent magnet generator for wind power applications. This paper derives analytical solutions for open-circuit field, armature reaction field, torque, back-emf, inductance and resistance of permanent magnet generators for wind power applications. And then, by presenting the variation of torque according to design parameters and by applying restrict conditions to it, we determine proper design parameter appropriate to rated power and speed. Finally, this paper also presents power conversion system resonable in wind power applications.

• 대한기계학회논문집B
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• 제33권12호
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• pp.1007-1013
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• 2009

The purposes of this study are to evaluate the power performance through CFD analysis and structural integrity through uni-directional FSI analysis in aerodynamic design and structure design of wind turbine blade. The blade was designed to generate the power of 2MW under the rated wind speed of 11 m/s, consisting of NACA 6 series, DU series and FFA series airfoil. The inside section of the blade was designed into D-spar structure and circular stiffener was placed to reinforce the structural strength in the part of hub. CFD analysis with the application of transitional turbulence model was performed to evaluate the power performance of blade according to the change of TSR and 2.024MW resulted under the condition of rated wind speed. TSR of 9 produced the maximum power coefficient and in this case, Cp was 0.494. This study applied uni-directional FSI analysis for more precise evaluation of structural integrity of blade, and the results of fiber failure, inter fiber failure and eigenvalue buckling analysis were evaluated, respectively. For the evaluation, Puck's failure criteria was applied and the result showed that fiber failure and inter fiber failure did not occur under every possible condition of the analysis. As a result, power performance and structural integrity of 2 MW blade designed in this study turned out to satisfy the initial design goals.

• 조명전기설비학회논문지
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• 제20권5호
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• pp.25-32
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• 2006

본 논문에서는 전철시스템의 직류모선에 발생하는 잉여분의 전력을 교류전원 측으로 회생시킬 수 있는 회생인버터시스템을 제안한다. 제안된 직류 전철용 회생인버터 시스템은 교류 전원 측 전류에 포함되어진 고조파를 제거할 수 있는 기능을 추가하였다. 회생인버터 모드에서는 전철의 감속에 의해 회생되는 에너지를 재사용할 수 있으며, 능동전력필터 모드에서는 정류기에 의해 발생되는 고조파 왜곡을 보상할 수 있다. 논문에서 회생용 인버터는 PWM DC/AC 인버터 알고리즘을 사용하였으며, 능동전력필터는 p-q 이론을 사용하였다. 시뮬레이션은 축소모델[3.7kW]과 동일하게 구성되었다. 시뮬레이션과 실험 결과로부터 두 가지 알고리즘이 실 모델[100kW]에서도 적용되어질 수 있음을 증명하였다.

• 해양환경안전학회지
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• 제20권5호
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• pp.586-592
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• 2014

본 연구에서는 BEMT(Blade Element Momentum Theory)에 의해 우선 정격 출력 100 kW인 수평축 조류 발전용 단일 터빈에대한 기본 형상 설계를 진행하고, CFD 해석을 통해 블레이드 주변 유동특성 파악 및 출력 성능 예측을 하였다. 기본적인 에어포일은 FFA-W3-301, DU-93-W210, NACA-63418을 사용하였다. 이를 바탕으로 상반회전 터빈의 특성을 고찰한 결과, 설계 주속비 5.17에서 최대 출력계수는 0.495이며, 터빈의 출력은 101.82 kW를 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.637-641
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• 1992

This paper presents a fundanental method to analyze and design a Single-sided Linear Induction Motor(SLIM) as a propulsion system for magnetic levitation vehicles of DAEJEON EXPO'93 in Korea. The performance characteristics of the designed SLIM are examinated by the thrust force, the normal force, the efficiency and the power factor according to the change of input frequency. The dimension of the SLIM is 1792mm long ${\times}$ 200mm width ${\times}$ 58mm high and the rated thrust is 1300 Newtons at the operating speed of 40 Km/h.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.194-194
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• 2004

This paper presents Single Phase SRM for the vacuum cleaner. The advantage of SRM is long life time, high suction power.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.492-494
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• 2006

Neutral line current is analyzed by the neutral line CF in nonlinear load balanced and unbalanced conditions. The worst nonlinear load condition is nonlinear balanced load condition, and It is below CFNL=1.194 that a neutral line current could not excess the rated value