• 한국해양공학회지
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• 제30권2호
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• pp.84-90
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• 2016

In this study, a six degree-of-freedom motion analysis of a wind-wave hybrid platform equipped with numerous wave energy converters (WECs) was carried out. To examine the effect of the WECs on the platform, an analysis of one-way coupling was carried out, which only considered the power take-off (PTO) damping of the static WECs on the platform. The equation of motion of a floating platform with mooring lines in the time domain was established, and the responses of the one-way coupled platform were then compared with the case of a platform without any coupling effects from the WECs. The hydrodynamic coefficients and wave exciting forces were obtained from the 3D diffraction/radiation pre-processor code WAMIT based on the boundary element method. Then, an analysis of the dynamic responses of the floating platform with or without the WEC effect in the time domain was carried out. All of the dynamics of a floating platform with multiple wind turbines were obtained by coupling FAST and CHARM3D in the time domain, which was further extended to include additional coupled dynamics for multiple turbines. The analysis showed that the PTO damping effect on platform motions was negligible, but coupled effects between multiple WECs and the platform may differentiate the heave, roll, and pitch platform motions from the one without any effects induced by WECs.

• 전력전자학회논문지
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• 제20권5호
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• pp.410-420
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5 MW-class medium-voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for a voltage source type topology, whereas a two-level converter is employed for current source type topology, considering the popularity in the industry. To match the required voltage level of 4160 V with the same switching device of IGCT as in the voltage source converter, two active switches are connected in series for the case of current source converter. Transient thermal modeling of a four-layer Foster network for heat transfer is done to better estimate the transient junction and case temperature of power semiconductors during various operating conditions in wind turbines. The loss analysis is confirmed through PLECS simulations. Comparison result shows that the VSC-based wind turbine system has higher efficiency than the CSC under the rated operating conditions.

• Composites Research
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• 제36권1호
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• pp.32-36
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• 2023

최근 탄소 중립 등 지속 가능한 발전을 위한 지구환경 문제가 대두되면서 기존 풍력터빈의 소재인 유리섬유 복합재의 폐기 시 처리 방안이 문제가 되고 있다. 이를 해결하기 위해 본 연구에서는 기존의 유리섬유 복합재를 대체할 수 있는 친환경 복합재인 아마섬유 기반 복합재를 활용하여 30kW 풍력터빈 블레이드를 제조하고 적합성을 평가하였다. 먼저 친환경 천연 아마섬유 복합재의 풍력터빈 블레이드 소재로 활용 가능성을 검증하기 위해 기계적 강도 시험을 수행하였으며, 그 결과 선행 아마섬유 복합재 물성 연구 대비 좀 더 우수한 강도가 측정된 것을 확인하였다. 또한 제작된 30kW 급 아마섬유 복합재 블레이드를 활용하여 아마섬유 복합재 블레이드의 정적강도를 측정하는 정적강도 성능평가 시험을 통하여 적합성을 확인하였다.

• 한국전자통신학회논문지
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• 제17권2호
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• pp.265-278
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• 2022

육·해상 풍력 프로젝트 성공여부는 사업의 경제성 확보에 중점을 두고 있으며, 이는 양질의 풍력자원 확보와 풍력단지 최적배치에 의해 좌우된다. 풍력단지를 배치하는 과정에서 주풍향을 고려한 풍력터빈들의 최적배치 방법이 중요하며, 이는 풍상측에 위치한 구조물을 통과하는 유체가 발생시키는 후류영향을 최소화시키는 것과 연관이 있다. 후류효과 예측성의 정확도는 이를 적절히 모의할 수 있는 후류모델과 모델링 기법에 의해 결정되어지며, 특히 산악 및 다도해지역과 같은 복잡지형에서는 고해상도 기반의 정확한 후류예측이 필수적으로 요구된다. 이에 본 논문에서는 상용 CFD 모델인 WindSim을 활용하여 국내 산악 복잡지형에 위치한 육상풍력단지 예정지의 후류모델별 민감도 분석을 통해 후류확산 형태를 분석하고 향후 복잡지형 풍력발전 프로젝트의 기초연구 자료로 활용하고자 한다.

• 신재생에너지
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• 제2권2호
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• pp.28-36
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• 2006

Numerical analysis of wind turbine scale effect was performed by using commercial CFD code, Fluent. For the numerical analysis of wind turbine, the three dimensional Navier-Stokes solver with various turbulence models was tested. As a turbulence mode, the realizable k-e turbulence model was selected for the simulation of wind turbines. To validate the present method, performance of NREL (National Renewable Energy Laboratory) Phase VI wind turbine model was analyzed and compared with its wind tunnel test and blind test data. Using the present method, numerical simulations for various size of wind tunnel models were carried out and characteristics were analyzed in detail. For wind tunnel test model, the size of nacelle may not be scaled down precisely because of available motor. The effect of nacelle size was also computed and analyzed though CFD simulation. The present results showed the good correlations in pre-stall region but much to be improved in post-stall region. In 2006 and 2007, the performance and the scale effect of standard wind turbine model will be tested in KARI(Korea Aerospace Research Institute) LSWT(Low Speed Wind Tunnel) and the present results will be validated with the wind tunnel data.

• Wind and Structures
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• 제24권4호
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• pp.333-350
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• 2017

Differing from the fixed-type, the dynamic motion of floating-type offshore wind turbines is very sensitive to wind and wave excitations. Thus, the sensing and monitoring of its motion is important to evaluate the dynamic responses to the external excitation. In this context, a monitoring system for sensing and processing the wind-induced dynamic motion of spar-type floating offshore wind turbine is developed in this study. It is developed by integrating a 1/00 scale model of 2.5MW spar-type floating offshore wind turbine, water basin equipped with the wind generator, sensing and data acquisition systems, real-time CompactRIO controller and monitoring program. The scale model with the upper rotatable blades is installed within the basin by means of three mooring lines, and its translational and rotational motions are detected by 3-axis inclinometer and accelerometers and gyroscope. The detected motion signals are processed using a real-time controller CompactRIO to calculate the acceleration and tilting angle of nacelle and the attitude of floating platform. The developed monitoring system is demonstrated and validated by measuring and evaluating the time histories and trajectories of nacelle and platform motions for three different wind velocities and for eight different fairlead positions.

• Wind and Structures
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• 제20권1호
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• pp.1-13
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• 2015

This study applied long-term wind speed data from Penghu and Dongjidao weather stations to simulate the wind energy production for eight onshore and one offshore wind farms at Penghu Island, Taiwan by a commercial software package, Wind Atlas Application Program (WAsP). In addition, the RET Screen software suite was also applied to analyze economic characteristics of these nine wind farms (WFs). The results show that the capacity factors (CFs) of the nine wind farms mentioned above are in the range of 44.5% to 49.1%. In addition, utilizing 1.8-MW wind turbines (WTs) for all onshore WFs was the most feasible selection among the four potential types of WTs (600, 900, 1,800 and 3,600 kW) considered. 3-MW WTs selected for the offshore WF can produce the most wind energy and the smallest wake loss among the three possible types of WTs (1, 2 and 3MW). As a consequence of implementing these WFs, the emission of about 680,977 tons carbon dioxide ($tCO_2$) into the local atmosphere in Penghu Island annually could be avoided. Finally, based on the payback periods achieved, the order of implementation of the considered WFs can be identified more clearly. Longmen WF should be the first priority, and the next one should be SiyuWF and so on. Besides, this study provides much useful information for WF planning on Penghu Island.

• 한국소음진동공학회논문집
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• 제22권12호
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• pp.1164-1171
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• 2012

Recently, researches related to the green energy generation systems have increased significantly. Among them wind turbines are the most spread practical green energy generation systems. In order to enhance the power generation capacity of the wind turbine blade, the length of wind turbine blade has increased. It might cause undesirable excessive dynamic loads. Therefore dynamic characteristics of a wind turbine blade system should be identified for a safe design of the system. In this study, the equations of motion of a wind turbine blade system undergoing gravitational force are derived considering wind force and pitch angle. Effects of wind speed, variation of pitch angle of the wind turbine blade, rotating speed, and the blade length on its stability characteristics are investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.959-960
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• 2007

The wind power has been used steadily since long ago, but the importance of it has been faded because of the abundant and convenient fossil energy. Now, due to the energy crisis, experiencing the environmental problems etc, the necessity of using it growing bigger. Because the small wind turbines under a few kW grade has the merits of setting up with low costs by individuals, and get the energy saving effects that, it has the secured, separate markets from the range systems, and the developing of it is continuously proceeding. The small wind turbine system must have the output power regulating system for the over wind speed, to run steadily in the various wind speed environment. In case of the small wind turbine system, to prevent the breaking and for safety, at the over wind speed, additional system is required, and in most cases, output power is restricted by mechanical means. In this paper, the furling system makes the tail and the head move to make the blades to the wind in slanted angle, restrict the output power at the over wind speed. In thesis, small prototype wind turbine is made, and analyzing the output power characteristics at the over wind speed, and to verify, through the logical study and tests.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1691-1692
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• 2008

In this paper, the adaptive neural network technique is proposed to control the speed of wind power generation system. For maximizing generated power effectively, adaptive neural algorithm based on SRWMM(Self Recurrent Wavelet Neural Network) is derived to on-line adjust the excitation winding voltage of the generator. Through computer simulations, it is shown that the proposed method can achieve smooth and asymptotic rotor speed tracking.