• 풍력에너지저널
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• 제15권1호
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• pp.11-20
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• 2024

As the generation capacity of floating offshore wind turbines increases, the wind load applied to each turbine increases. Due to such a high wind load, the capacity of transport equipment (such as tugboats or cranes) required in the transportation and installation phases must be much larger than that of previous small-capacity wind power generation systems. However, for such an important wind load prediction method, the simple formula proposed by the classification society is generally used, and prediction through wind tunnel tests or Computational Fluid Dynamics (CFD) is rarely used, especially for a concept or initial design stages. In this study, the wind load of a 10 MW class floating offshore wind turbine was predicted by a simplified formula and compared with results of wind tunnel tests. In addition, the wind load coefficients at each stage of fabrication, transportation, and installation are presented so that it can be used during a concept or initial design stages for similar floating offshore wind turbines.

• 한국소음진동공학회논문집
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• 제17권2호
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• pp.114-120
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• 2007

Vibration performance of a 6 kW stand-alone wind turbine(W/T) generator is investigated under the wind environment of Daegwanryung mountain area. In the W/T, wind condition, power performance and structural stability are correlated each other An integrated monitoring system which consists of accelerometers, anemometers, power meters and auxiliary sensors for atmospheric data are constructed to measure the required data simultaneously. Based upon the data acquired over a long period of time, vibration performance of the W/T structure is estimated with annual wind data and generating power performance. Within the operating speed range, possibility of severe nitration is diagnosed. Vibration sources are identified and countermeasures are proposed. The goal of the study is to offer the basic information on W/T vibration performance at the design stage of a small stand alone W/T structure.

• 한국지능시스템학회논문지
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• 제19권6호
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• pp.766-772
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• 2009

일반적으로 풍력발전은 광범위한 영역에 지속적인 바람을 요구하는 대형 시스템 위주로 개발이 되어왔다. 그러나 소형 풍력발전 시스템은 사용자에게 보다 친숙하고, 대형에 비해 보다 광범위한 적용이 가능하다는 점 때문에 최근 이에 대한 관심이 증가되고 있는 실정이다. 이에 본 연구에서는 배터리 충전에 효과적으로 도입될 수 있는 도시형 풍력발전을 위한 프로토타입 시스템에 대해 기술하며, 프로토타입 시스템에 효과적으로 도입될 수 있는 인공신경망 기반의 최대 전력점 추종 알고리즘을 제안하고자 한다. 또한 Matlab기반의 다양한 시뮬레이션 및 실제 시스템 설계를 통해 제안된 기법의 유용성을 확인하고자 한다.

• 한국태양에너지학회 논문집
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• 제33권1호
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• pp.40-47
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• 2013

An aerodynamic design tool was developed for small wind turbine blades based on the blade element momentum theory. The lift and drag coefficients of blades that are needed for aerodynamic blade design were obtained in real time from the Xfoil program developed at University of Illinois. While running, the developed tool automatically accesses the Xfoil program, runs it with proper aerodynamic and airfoil properties, and finally obtains lift and drag coefficients. The obtained aerodynamic coefficients are then used to find out optimal twist angles and chord lengths of the airfoils. The developed tool was used to design a wind turbine blade using low Reynolds number airfoils, SG6040 and SG6043 to have its maximum power coefficient at a specified tip speed ratio. The performance of the blade was verified by a commercial code well known for its prediction accuracies.

• 한국태양에너지학회 논문집
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• 제38권2호
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• pp.15-31
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• 2018

A program to design a small capacity wind turbine blade is proposed in this study. The program is based on a matlab GUI environment and designed to perform blade design based on the blade element momentum theory. The program is different from other simulation tools available in a point that it can analyze the side-furling power regulation mechanism and also has an algorithm to find out optimal torque schedule above the rated wind speed region. The side-furling power regulation is used for small-capacity horizontal axis wind turbines because they cannot use active pitch control due to high cost which is commonly used for large-capacity wind turbine. Also, the torque schedule above the rated wind speed region should be different from that of the large capacity wind turbines because active pitching is not used. The program developed in this study was validated with the results with FAST which is the only program that can analyze the performance of side-furled wind turbines. For the validation a commercial 10 kW wind turbine data which is available in the literature was used. From the validation, it was found that the performance prediction from the proposed simple program is close to those from FAST. It was also found that the optimal torque scheduling from the proposed program was found to increase the turbine power substantially. Further experimental validation will be performed as a future work.

• Journal of Power Electronics
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• 제11권4호
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• pp.568-575
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• 2011

This paper proposes an application of energy storage devices (ESD) for low-voltage ride-through (LVRT) capability enhancement and power smoothening of doubly-fed induction generator (DFIG) wind turbine systems. A grid-side converter (GSC) is used to maintain the DC-link voltage. Meanwhile, a machine-side converter (MSC) is used to control the active and reactive powers independently. For grid disturbances, the generator output power can be reduced by increasing the generator speed, resulting in an increased inertial energy of the rotational body. Design and control techniques for the energy storage devices are introduced, which consist of current and power control loops. Also, the output power fluctuation of the generator due to wind speed variations can be smoothened by controlling the ESD. The validity of the proposed method has been verified by PSCAD/EMTDC simulation results for a 2 MW DFIG wind turbine system and by experimental results for a small-scale wind turbine simulator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1165-1169
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• 2006

Vibration characteristics of a small stand alone W/T(wind turbine) system are experimentally and theoretically investigated. Vibration resonance of the tower-cable system is monitored and the data are analysed with the analytical results. To predict the resonance speed of the cable supported WIT. Rayleigh-Ritz method is applied to the tower-guy cable coupled system. Parametric study on the relation of the cable tension. cable elasticity and resonance frequency is carried out. Results of the study are utilized to design the stable structure of small size wind turbines which consist of a pivoted tower and guy cables.

• 항공우주시스템공학회지
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• 제2권2호
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• pp.1-7
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• 2008

Recently the wind energy has been alternatively used as a renewable energy resource instead of the mostly used fossil fuel due to its lack and environmental issues. This work is to propose a structural design and analysis procedure for development of the low noise 100W class small wind turbine system which will be applicable to relatively low speed region like Korea and for the domestic use. Structural analysis including load cases, stress, deformation, buckling, vibration and fatigue life was performed using the Finite Element Method, the load spectrum analysis and the Miner rule. In order to evaluate the designed structure, the structural test was carried out and its test results were compared with the estimated results. In addition, the blade should be safe from the impact damage due to FOD(Foreign Object Damage) including the bird strike. In order to analize the bird strike penomena on the blade, MSC. Dytran was used, and the applied method Arbitrary Lagrangian-Eulerian was evalud by comparison with the previous study results.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.64.1-64.1
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• 2011

Small horizontal axis wind turbines (HAWTs) can be used to produce power in areas where the wind conditions are not favorable or optimal for large HAWTs. A newly designed airfoil for use in small HAWTs was analyzed in CFD to predict the aerodynamic performance at various Reynolds numbers over a various angles of attack. The coefficient of lift and drag, CL and CD, and the pressure distribution over the airfoil was obtained. It was found that the airfoil could achieve very good aerodynamic characteristics. The results of the numerical analysis will be compared against experimental data for validation purposes.

• 한국기계가공학회지
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• 제17권1호
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• pp.122-129
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• 2018

This study conducted a seismic qualification analysis of small savonius style vertical axis wind turbine(VAWT) using finite element method(FEM). The modal analysis was performed on the wind turbine structure to check the occurrence of resonance caused by the rotation of gearbox and windmill blades. Next, it conducted a seismic response spectrum analysis due to horizontal and vertical seismic load of required response spectrum of safe shutdown earthquake with 5 % damping(RRS/SSE 5%) of KS C IEC 61400 and conducted a static analysis due to deadweight and wind load. The total maximum stress of the VAWT structure was calculated by adding the maximum stresses due to each load case using the square root of the sum of the squares(SRSS) method. Finally, the structural safety of the VAWT structure was verified by comparing the total maximum stress and the allowable stress.