• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.177-186
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• 2019

Wind power tower has been used to augment the performance of VAWT (Vertical Axis Wind Turbine). However, inappropriately designed wind power tower could reduce the performance of VAWT. Hence, an optimization study was conducted on a wind power tower. Six design variables were selected, such as the outer radius and the inner radius of the guide wall, the adoption of the splitter, the inner radius of the splitter, the number of the guide wall and the circumferential angle. For the objective function, the periodic averaged torque obtained at the VAWT was selected. In the optimization, Design of Experiment (DOE), Genetic Algorithm (GA), and Artificial Neural Network (ANN) have been applied in order to avoid a localized optimized result. The ANN has been continuously improved after finishing the optimization process at each generation. The performance of the VAWT was improved more than twice when it operated within the optimized wind power tower compared to that obtained at a standalone.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.114-123
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• 2018

Wind power tower (WPT) has been used to augment the performance of vertical axis wind turbine (VAWT). However, the performance of the WPT depends on several design parameters, such as inner and outer radius, or number of guide walls. Therefore, an experimental study was conducted to investigate efficient design parameters on the WPT. A wind tunnel was utilized and its test section dimension was 2m height and 2.2m width. One story model of the WPT was manufactured with seven guide walls and a VAWT was installed within the WPT. Three different sizes of guide walls were applied to test with various design parameters. The power coefficients were measured along the azimuthal direction in a state of equal inlet velocity in order to compare its performance relatively. The experimental results showed that the gap between the inner radius of the WPT and the rotating radius of the VAWT was a major parameter to improve the performance of VAWT within the WPT.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1455-1462
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• 2012

As the size of a wind turbine increases, the mechanical structure has to have an increasing mechanical stiffness that is sufficient to withstand mechanical fatigue loads over a lifespan of more than 20 years. However, this leads to a heavier mechanical design, which means a high material cost during wind turbine manufacturing. Therefore, lightweight design of a wind turbine is an important design constraint. Usually, a lightweight mechanical structure has low damping. Therefore, if it is subjected to a disturbance, it will oscillate continuously. This study deals with the active damping control of a wind turbine tower. An algorithm that mitigates the mechanical loads of a wind turbine tower is introduced. The effectiveness of this algorithm is verified through a numerical simulation using GH Bladed, which is a commercial aero-elastic code for wind turbines.

• Composites Research
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• v.25 no.2
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• pp.54-61
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• 2012

In this study, a specific structural design procedure for 2 MW class glass/epoxy composite wind turbine system towers is newly proposed through load case study, trade-off study, optimal structural design and structural analysis. Optimal tower design is very important because its cost is about 20% of the wind turbine system's cost. In the structural design of the tower, three kinds of loads such as wind load, blades, nacelle and tower weight and blade aerodynamic drag load should be considered. Initial structural design is carried out using the netting rule and the rule of mixture. Then the structural safety and stability are confirmed using a commercial finite element code, MSC NASTRAN/PATRAN. The finally proposed tower configuration meets the tower design requirements.

• Journal of Wind Energy
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• v.2 no.1
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• pp.61-67
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• 2011

In the present study, numerical unsteady simulations of the NREL Phase VI wind turbine in downwind operation conditions were conducted to investigate rotor-tower interaction. The calculations were performed using an unstructured mesh, incompressible Reynolds-averaged Navier-Stokes flow solver. To capture the unsteady effects associated with the tower shadow between the rotor blades and the tower, the wind turbine was modelled including the rotor, tower, hub, and nacelle. The present results generally showed good agreements with available experimental data. At the lowest wind speed, the pressure distribution was characterized by a complete collapse of the suction peak on the blade when the blade passes through the tower wake. It was found that unsteady effects play a significant role in the response of the blades.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.3
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• pp.201-209
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• 2011

An unsteady RANS analysis study of the 3-D flow around the NREL Phase VI horizontal axis wind turbine(HAWT) was performed using sliding mesh approach. Two different analysis models such as rotor-only and rotor with tower/nacelle were constructed to investigate the blade/tower interaction. Analysis results for the rotor with tower/nacelle were compared with the corresponding NREL's experimental data which produced fairly good validation of the present CFD model. Comparison of flows around those two models also clearly showed the blade/tower interaction even it was small for upwind configuration. Other visualization results and integrated aerodynamic loads including torque of the blade demonstrated the effective unsteady flow simulation capability of the present CFD model.

• 기계와재료
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• v.21 no.2
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• pp.50-73
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• 2009

본 고는 중대형 풍력터빈의 핵심부품인 로터 블레이드, 대형베어링, 증속기, 발전기, 전략변환장치, 타워 등에 사용되는 주요재료에 대한 설명과 제조방법 및 평가 방법 등에 대해 다루어 졌다. 일반적으로 풍력터빈을 구성하는 소재는 금속소재와 비금속재료로 구분되며, 비금속재료는 대부분 복합재료로써 풍력 블레이드에 적용되고 있다. 현재 육상용 풍력터빈의 한계를 극복하기 위한 대안으로, 해상용 풍력터빈에 대한 관심이 집중되고 있으며, 이러한 극지 해상의 대형 시스템에 활용되고 있는 금속소재의 경우, 고강도, 저온인성, 내피로, 내식성 등이 우수한 강재를 요구하기에 이르렀다. 이에 따라, 여러 소재 측면의 요구를 충족하기 위한 소재설계의 비중이 점차 고조되고 있으며, 이러한 시점에 본 고를 통해 풍력터빈에 활용되고 있는 소재의 전반적인 내용과 관련 소재부품의 제조 및 평가 방법등의 이해를 돕고자 한다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.38 no.7
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• pp.29-38
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• 2009

지난 20년간 급속한 발전을 통하여 회전 블레이드의 직경이 126 m, 나셀까지의 높이가 약 130 m에 이르는 6,000 kW의 용량을 가지는 풍력발전기가 개발되었다. 세계적으로 풍력발전의 필요성과 중요성이 인식되어 2008년 현재 약 120,000 MW의 설치 용량을 기록하고 있다. 풍력터빈(wind turbine)과 그 부품의 기계적인 성능평가의 종류와 방법은 많은 사람들의 관심인 것으로 판단한다. 우선 풍력터빈을 구성하는 주요 핵심부품은 블레이드, 증속장치, 발전기 등이며, 세부 구성 부품으로 허브, 핏치와 요베어링, 주축베어링, 타워 등이 있다. 주요핵심 부품인 블레이드, 증속기, 발전기 등의 성능평가가 중요한 이슈이다. 또한 모든 구성품을 조립하여 초기의 설계사양에 따라서 제조되고 최종성능이 발휘되는지 여부를 현장시험을 통하여 성능평가과정을 거치게 되는데 이 과정은 풍력터빈의 성능평가라고 하며 주요 평가대상은 출력성능(power performance), 소음(noise), 하중(load), 전력품질(power quality) 등 4가지 항목을 집중적으로 측정하여 개발된 풍력터빈의 전반적인 성능을 평가하게 된다. 본 투고에서는 핵심부품인 블레이드, 증속기, 발전기에 대한 시험기술과 풍력터빈의 성능평가 항목인 4개 측정 항목에 대하여 기술하였다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.4-6
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• 2008

본 논문에서는 2.5MW급 풍력터빈에 적용된 이중여자 권선형 유도발전기 제어를 위한 풍력발전시스템의 핵심요소인 전력변환장치 제작기술과 풍력발전시스템 제어를 위한 요소기술에 대해 기술한다. 2.5MW급 풍력터빈을 계통연계하기 위해서는 풍력제어기와 컨버터를 설계하고 상호 인터페이스등을 고려하여 적절한 풍속조건에서 계통측에 발전전력을 전달하여야 한다. 또한, 최근 계통 사업자측에서 요구하는 Grid-code에 대응하기 위한 제어알고리즘을 설계하여야 하고, 타워의 진동억제를 위한 축진동 억제 알고리즘 등을 추가로 전력변환장치에 적용하여야 한다. 따라서 본 논문에서는 2.5MW급 풍력터빈용 PCS개발을 위한 각종 제어알고리즘과 H/W설계기술에 대해서 기술한다.

• Journal of Wind Energy
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• v.5 no.1
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• pp.43-49
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• 2014

Primarily, tower loads of a wind turbine arise from aerodynamic effect and a top head mass. But sometime asymmetric loads of rotor also affect on the tower loads. Especially ice formation on two blades out of three causes the asymmetric loads, because the ice formation on blades lead to large rotating mass imbalance. This rotating mass imbalance of rotor affects tower fatigue loads. So design load cases of ice formation on blade should be considered in the fatigue design loads of the tower according to GL guideline 2010. This paper describes the change of tower fatigue loads following increase of tower height in the condition of ice formation. Finally, the optimal operation strategy is examined in order to reduce tower fatigue design loads.