Topic
Blade pitch
About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.
Papers published on a yearly basis
Papers
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TL;DR: A novel algorithm for wind speed estimation in wind-power generation systems is proposed, based on adaptive neuro-fuzzy inference system (ANFIS), which is implemented using Matlab/Simulink and the performances are investigated.
35 citations
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11 Jun 2008TL;DR: A series of numerical results show that the wind turbine can be controlled to achieve maximum energy capture.
Abstract: The emergence of wind turbine systems for electric power generation can help satisfy the growing global demand. To maximize wind energy captured in variable speed wind turbines at low to medium wind speeds, a robust control strategy is presented. The proposed strategy simultaneously controls the blade pitch and tip speed ratio, via the rotor angular speed, to an optimum point at which the efficiency constant (or power coefficient) is maximum. The control method allows for aerodynamic rotor power maximization without the restrictions of exact wind turbine model knowledge. A series of numerical results show that the wind turbine can be controlled to achieve maximum energy capture.
35 citations
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34 citations
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TL;DR: In this paper, the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine were investigated.
Abstract: The magnitude and stability of power output are two key indices of wind turbines. This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine. First, wind speed models, particularly the wind shear model and the tower shadow model, are described in detail. The widely accepted tower shadow model is modified in view of the cone-shaped towers of modern large-scale wind turbines. Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory. Results indicate that power fluctuation is mainly caused by tower shadow, whereas power loss is primarily induced by wind shear. Under steady wind conditions, power loss can be divided into wind farm loss and rotor loss. Wind farm loss is constant at 3α(3α–1)R2/(8H2). By contrast, rotor loss is strongly influenced by the wind turbine control strategies and wind speed. That is, when the wind speed is measured in a region where a variable-speed controller works, the rotor loss stabilizes around zero, but when the wind speed is measured in a region where the blade pitch controller works, the rotor loss increases as the wind speed intensifies. The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.
34 citations
01 Jan 2013
TL;DR: In this paper, the effects of pitch angle and blade camber on the flow characteristics and performance of a small-size Darrieus vertical axis wind turbine (VAWT) were investigated.
Abstract: This study builds up a simulation model, via Ansys/Fluent, to investigate the effects of pitch angle and blade camber on the flow characteristics and performance of small-size Darrieus vertical axis wind turbine (VAWT). The VAWT system is driven by a uniform wind speed (10 m/s). The blade profiles with three different cambers are NACA0012, 2412 and 4412, respectively; and the pitch angles vary between 10 and -10. The user-defined function is employed to calculate the instantaneous moments produced by all the blades and rotate the VAWT system from rest. The flow structures, the vorticity fields and the per- formance on the blades will be addressed; also, the self-starting ability and the moment coefficient of the VAWT system are discussed. For the blade profiles studied, the initial acceleration is the largest at h =- 10 and decreases monotonously as the pitch angle increases from h =- 10 to h = 10. Further, at the same pitch angle, the larger the camber of the blade (NACA4412), the better is the self-starting ability of the VAWT system. The maximum root mean square moments have the maximum values at h = 5 for all the blade profiles studied herein. The root mean square moments for NACA2412 are much higher than those of NACA0012 and 4412 at all pitch angles. However, the root mean square moments for NACA4412 are relatively insensitive to the variations in pitch angles.
34 citations