• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.25-25
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• 2010

In this paper, we have investigated the electrical characteristics for solar-cell and wind power generator hybrid system. The output of electricity for solar cell - wind generator hybrid system were investigated according to the weather conditions at Naju province.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.205-213
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• 2014

A wind generator (WG) maximum power point tracking (MPPT) system is presented here. It comprises of a variable-speed wind generator, a high-efficiency boost-type dc/dc converter and a control unit. The advantages of the aimed system are that it does not call for the knowledge of the wind speed or the optimal power characteristics and that it operates at a variable speed, thus providing high efficiency. The WG operates at variable speed and thus suffers lower stress on the shafts and gears compared to constant-speed systems. It results in a better exploitation of the available wind energy, especially in the low wind-speed range of 2.5-4.5 m/s. It does not depend on the WG wind and rotor-speed ratings or the dc/dc converter power rating. Higher reliability, lower complexity and cost, and less mechanical stress of the WG. It can be applied to battery-charging applications.

• Journal of Power Electronics
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• 제8권4호
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• pp.345-353
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• 2008

In this paper, a novel loss minimization of an induction generator in wind energy generation systems is presented. The proposed algorithm is based on the flux level reduction, for which the generator d-axis current reference is estimated using support vector regression (SVR). Wind speed is employed as an input of the SVR and the samples of the generator d-axis current reference are used as output to train the SVR algorithm off-line. Data samples for wind speed and d-axis current are collected for the training process, which plots a relation of input and output. The predicted off-line function and the instantaneous wind speed are then used to determine the d-axis current reference. It is shown that the effect of loss minimization is more significant at low wind speed and the loss reduction is about to 40% at 4[m/s] wind speed. The validity of the proposed scheme has been verified by experimental results.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1806-1813
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• 2012

본 논문은 도서지역에서 현실적으로 가장 간단히 적용될 수 있는 풍력-디젤 하이브리드 발전시스템의 모델링 방법을 제시하였다. 모델링 대상으로는 풍력발전기는 농형유도발전기를, 디젤발전기는 동기발전기를 대상으로 하였고, 각각에 대한 파라미터 설정과 제어기의 모델링은 현재 제작 및 판매되고 있는 소용량급들에 대한 자료수집과 분석을 통하여 도출된 기준값에 근거하였다. 제안된 풍력-디젤 하이브리드 발전시스템 모델링방법의 타당성을 입증하기 위하여 국내 낙도지역을 대상으로 하여 모델링하고, 그 결과를 시뮬레이션하여 고찰하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1351-1354
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• 2002

Wind farm which are composed with wind turbine generators can be a good alternatives to solve environmental problem and solutions to cope with energy crisis for using wind energy. Until now, these wind turbine generators have been being studied on the viewpoint of only active power control for reducing the burden of main grid. In this control scheme, we might demand a reactive power compensator in order to make reparation for the reactive power produced from wind turbine generator itself. Therefore, if the reactive power as well as active power of wind turbine generator were controlled according to the demand of reactive power, the installation of a additional reactive power compensator could be reduced. This paper presents the control method of a active and reactive power for wind turbine generators by means of SVPWM(Space Vector Pulse Width Modulation) inverting method and describes a operational coordination of wind turbine generators. The proposed power control algorithm can simply produce the output power of wind turbine generator needed in wind farm, which can reduce the power of main grid more and exclude a supplementary reactive power compensator. We assumed that wind farm are composed with two kinds of wind turbine generators, AC/DC/AC and induction generator types.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.539-541
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• 2009

A severely cold weather condition of King Sejong Station, Antarctica becomes a very severe condition for an installation/operation of wind generation system. When the existing wind generation system works, it may cause a damage and destruction of wind generation system and can bring about big problems in terms of the power quality. Accordingly, it is essential to obtain technologies for the installation and operation of small wind generation system for the polar region's wind generation, and to assess and demonstrate the performance in the severely-cold environment and the polar wind generation system's development, supplementation, alteration. Also, as the available power of King Sejong Station, Antarctica, the diesel generator has been mainly used, and the wind generator has been used in the hybrid form. Wind generation and diesel generation has the different load following control each other. In the wind generation, the generated power very rapidly changes according to the change of the velocity of the wind. On the other hand, the diesel generation shows very gentle change in the velocity of output. Therefore, the study is intended to analyze the 10kw small wind generator-diesel generator's power quality of King Sejong Station, Antarctica, which is the hybrid system installation area.

• 제어로봇시스템학회논문지
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• 제19권1호
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• pp.34-39
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• 2013

This paper proposes the implementation of robust fuzzy controller for designing intelligent wind farm and mitiagating the fluctuation of wind power generator. The existing researches are limited to individual wind turbine with variable speed so that it is necessary to study the multi-agent wind turbine power system. The scopes of these studies include from the arrangements of each power turbine to the control algorithms for the wind farm. For solving these problems, we introduce the composition of intelligent wind farm and use the T-S (Takagi-Sugeno) fuzzy model which is suitable for designing fuzzy controller. The control object in wind farm enables the minimizing the fluctuation of wind power generator. Simulation results for wind fram which is modelled as mathematically are demonstrated to visualize the feasibility of the proposed method.

• 대한전기학회논문지:전력기술부문A
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• 제53권11호
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• pp.589-595
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• 2004

This paper presents a modeling and simulation of a grid-connected wind turbine generation system with respect to wind variations, starting of large induction motor and three-phase fault in the system, and investigates voltage variations of the system for disturbances. It describes the modeling of the wind turbine system including the drive train model, induction generator model, and grid-interface model on MATLAB/Simulink. The simulation results show the variation of the generator torque, the generator rotor speed, the pitch angle, terminal voltage, system voltage, fault current, and real/reactive power output, etc. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction for wind speed variations, starting of a large induction motor causes a voltage sag due to a large starting current, and a fault on the system influences on the output of the wind turbine generator.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.469-471
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• 2005

Wind farms employs induction generators which are two type, one is Squirrel cage for fixed speed wind turbines and the other is Wound induction generator (doubly fed induction generator DFIG) for variable speed wind turbines. this paper describes grid connection scheme of wind power system using two type induction generators and simulation results show the characteristics of two type induction generators.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권10호
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• pp.497-504
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• 2005

For maximum output power, wind turbines are usually controlled at the speed which is determined by the optimal tip-speed ratio. This method requires information of wind speed and the power conversion coefficient which is varied by the pitch angle control. In this paper, a new maximum output power control algorithm using fuzzy logic control is proposed, which doesn't need this information. Instead, fuzzy controllers use information of the generator speed and the output power. By fuzzy rules, the fuzzy controller produces a new generator reference speed which gives the maximum output power of the generator for variable wind speeds. The proposed algorithm has been implemented for the 3[kW] cage-type induction generator system at laboratory, of which results verified the effectiveness of the algorithm.