Results 221 to 230 of about 75,453 (258)

Wind energy from turbulence: Constant tip speed ratio operation

Solar Energy, 1985
Abstract The ability of a wind machine, operating at constant tip speed ratio, to extract power from the turbulent eddy fluctuations in the wind is examined. A model is constructed relating the inertia of the machine to its ability to follow the fluctuations. The model includes a transfer function from which a cutoff frequency can be predicted.
Manwell, JF, KIRCHHOFF, RH
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Maximum wind turbine performance at low tip speed ratio

Journal of Renewable and Sustainable Energy, 2015
Wind turbines can approach the Betz-Joukowsky limit on maximum power only at sufficiently high tip speed ratio: in practice, for ratios in excess of about seven. This paper analyses the performance of a turbine with an infinite number of blades as the tip speed ratio decreases to zero, beginning with the two traditional ways of determining the maximum ...
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Effects of tip speed ratio on wind turbine wake meandering

Journal of Fluid Mechanics
This study utilises large-eddy simulation with the actuator line model to examine the effects of the tip speed ratio (TSR) on the wake-meandering characteristics of a wind turbine in uniform and turbulent inflows. It is shown that as the TSR grows, the onset position of the wake meandering moves closer to the rotor, and the magnitude of wake ...
Yan Wang, Guihua Zhao, Guoliang Liu, Yongze Zhou, Mingwei Ge, Zhen Ouyang, Zijing Ding, Ruifeng Hu   +7 more
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Online estimation of the power coefficient versus tip-speed ratio curve of wind turbines

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013
Wind turbines are one of the main sources of renewable energy worldwide. Although large wind turbines in the MW range are popular, small wind turbines of several kW can also have a valuable contribution since they can be installed in a more decentralized manner. However, the energy yield of these small wind turbines still needs improvement.
Jeroen D. M. De Kooning, Louis Gevaert, Jan Van de Vyver, Tine L. Vandoorn, Lieven Vandevelde   +4 more
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Tip speed ratio control of wind turbine generating system connected in series

2011 International Conference on Electrical Machines and Systems, 2011
Experimental and simulated investigations of tip speed ratio control for a wind turbine generating system consisting of series connected two wind turbine/generators and a current-source thyristor inverter are carried out. It is confirmed that tip speed ratios of the individual turbines can be controlled almost constant when wind velocities fluctuated ...
Hiroyuki Yokoyama, Fujio Tatsuta, Shoji Nishikata   +2 more
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Performance of a High Tip Speed Ratio H-Darrieus in the Skewed Flow on a Roof

41st Aerospace Sciences Meeting and Exhibit, 2003
Small wind turbines sited on a flat roof have good opportunities to become widespread. They operate in the accelerated wind above the roof and deliver the power where it is needed. Since the power produced offsets that which would otherwise be bought from the utility, they reduce energy demand and bills from the utility. Furthermore excess power can be
Sander Mertens, Gijs van Kuik, Gerard van Bussel   +2 more
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Performance and Loads of Variable Tip Speed Rotorcraft at High Advance Ratios

2015
This dissertation presents a lifting-line, comprehensive approach to predicting the performance and loads of high advance ratio rotorcraft. At high advance ratios, the reverse flow region is large and its unique aerodynamics impacts the rotor performance and dynamics more than at conventional airspeeds where they are often ignored.
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Ideal wind turbine performance at very low tip speed ratio

Journal of Renewable and Sustainable Energy, 2014
At very low tip speed ratios, wind turbine rotors behave similarly to stationary wings for which the well-known lifting line analysis gives the optimal loading. Lifting line analysis is applied to a stationary rotor of N blades for N = 1, 2, and 4.
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Evaluation of the MPPT performance in small wind turbines by estimating the tip-speed ratio

2013 48th International Universities' Power Engineering Conference (UPEC), 2013
In this paper, a method for online estimation of the tip speed ratio (TSR) of small wind turbines is presented, in order to evaluate the MPPT performance. Unlike obvious methods, for which an encoder or resolver is needed, the presented method only requires measurements of the wind speed and the generator current. Firstly, the accuracy of the presented
Louis F. M. Gevaert, Jeroen D. M. De Kooning, Tine L. Vandoorn, Jan Van de Vyver, Lieven Vandevelde   +4 more
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Cylindrical Vortex Model of a Rotor of Finite or Infinite Tip-Speed Ratios

2017
A simple vortex model of a rotor with infinite number of blades and constant circulation is presented in this chapter. The model consists of a root vortex, a right semi-infinite vortex cylinder of tangential and longitudinal vorticity, and a bound vortex disk (actuator disk) of radial vorticity. This model was briefly presented in Sect. 5.2.3 The model
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