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Blade pitch

About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.


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Patent
06 Apr 1981
TL;DR: In this article, a wind turbine rotor speed control for ensuring a constant rotational speed within tight tolerances includes a self-sufficient rotor (16) incorporating aerodynamic and mechanical devices to provide the control.
Abstract: A wind turbine rotor speed control for ensuring a constant rotational speed within tight tolerances includes a self-sufficient rotor (16) incorporating aerodynamic and mechanical devices to provide the control. There is a fixed turbine blade (26) adapted to be mounted on a shaft (14) for rotation therewith, the fixed blade (26) having pivotal blade tips (28) at its respective ends. The pitch control of the blade tips regulates the rotor speed. Aerodynamic tabs (180) are pivotally secured adjacent each of the ends of the respective trailing edges (34, 36) of the fixed blade. The relative wind acts on each tab which is connected to a series of links (188-168) and pitch cams (86) to regulate the pitch of the blade tips from a feathered position (210), to a cut-in position (212), to a rated wind position, and vice-versa. There are torque cams (60) actuated by torsional strain on the shaft bearing which is connected to the shaft (14) and to the pitch cams (86) by a series of links ( 52, 54) so that as the wind approaches its rated velocity value the pitch cams (86) become ineffective (228) and the torque cams (60) take over the speed control. There are also overspeed centrifugal devices (80) connected to the pitch cams (86) to cause the blade tips (28) to feather in emergency overspeed conditions so as to stop the rotor (16).

68 citations

Journal ArticleDOI
TL;DR: In this article, a new wind turbine generator system (WTGS) is introduced, and its mathematical model, blade pitch control scheme, and nonlinear simulation software for the performance prediction are presented.

67 citations

Patent
17 May 2005
TL;DR: In this paper, a pitch controlled wind turbine blade (5) consisting of a pressure surface side (14) and a leeward surface side(13), where the surfaces (13, 14) established a leading edge and a trailing edge (7).
Abstract: The invention relates to a pitch controlled wind turbine blade (5) comprising a pressure surface side (14) and a leeward surface side (13), where the surfaces (13, 14) established a leading edge (6) and a trailing edge (7). The blade (5) comprises turbulence generating means (10) wherein said means are placed on the leeward surface sides (13) of the wind turbine blade (5) and at the outer section (OS) of the wind turbine blade (5) in direction of the blade tip (8). The invention further relates to a wind turbine (1) comprising at least two pitch controlled wind turbine blades (5) and pitch controlling means for pitching the blades (5). The blades (5) comprise turbulence generating means (10) wherein said means are placed on the leeward surface sides (13) of the wind turbine blades (5) and at the outer section (OS) of the wind turbine blades (5) in direction of the blade tips (8).

67 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of the number of blades, rotational speed, and pitch amplitude on the performance and efficiency of a cyclorotor for a micro air vehicle were investigated.
Abstract: Performance and flowfield measurements were conducted on a small-scale cyclorotor for application to a micro air vehicle. Detailed parametric studies were conducted to determine the effects of the number of blades, rotational speed, and blade pitching amplitude. The results showed that power loading and rotor efficiency increased when using more blades; this observation was found over a wide range of blade pitching amplitudes. The results also showed that operating the cyclorotor at higher pitching amplitudes resulted in improved performance, independently of the number of blades. A momentum balance performed using the flowfield measurements helped to quantify the vertical and sideward forces produced by the cyclorotor; these results correlated well with the force measurements made using load balance. Increasing the number of blades increased the inclination of the resultant thrust vector with respect to the vertical because of the increasing contribution of the sideward force. The profile drag coefficient of the blade sections computed using a momentum deficit approach correlated well with typical values at these low chord Reynolds numbers. Particle image velocimetry measurements made inside the cage of the cyclorotor showed that there are rotational flows that, when combined with the influence of the upper wake on the lower half of the rotor, explain the relatively low efficiency of the cyclorotor.

67 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202377
2022163
202184
2020110
2019105
2018109