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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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Journal ArticleDOI
TL;DR: In this paper, a new control technique is presented to attenuate the steep and large volatile dynamics during turbine switching while preserving the original system structure so that the established system stability still holds.
Abstract: Modern variable speed wind turbines operate within a large range of wind speeds. Control of such a turbine is partitioned in two modes: a low wind speed mode and a high wind speed mode. Depending on the prevailing wind speed, a turbine is controlled to switch between these two modes. During mode switching, critical dynamics of the turbine such as the output power and mechanical loads can experience steep, large changes even though the switching action is Lyapunov as well as input–output stable. In this work, a new control technique is presented to attenuate the steep and large volatile dynamics during turbine switching while preserving the original system structure so that the established system stability still holds. An algorithm that modifies the generator torque control law in the low wind speed mode is developed to reduce the steep change of turbine power and torque. A Proportional-integral (PI) control of blade pitch angle in the high wind speed mode is proposed to optimize the system power variation and power generation. Simulations conducted under various wind speed classes demonstrate the effectiveness of the proposed control design.

21 citations

Patent
Shigeo Yoshida1
29 Jun 2005
TL;DR: In this article, an independent pitch control unit capable of independently controlling pitch angles of the blades of a horizontal axis wind turbine is presented. And the pitch angles are sequentially reversed one by one.
Abstract: A horizontal axis wind turbine includes: a rotor having a hub and at least two or more blades; a nacelle for pivotally supporting the rotor through a rotating shaft connected to the hub; a tower for supporting the nacelle; and an independent pitch control unit capable of independently controlling pitch angles of the blades, respectively, wherein the independent pitch control units control the pitch angles so that all the blades are made in a full feather position in case of a wind speed not less than a predetermined value, and subsequently controls the pitch angles of the respective blades so as to be sequentially reversed one by one, and further subsequently, carries out control so that the wind turbine idles in an all-blade negative feather position where the pitch angles of all the blades are reversed.

21 citations

Journal ArticleDOI
TL;DR: In this article, an approach to helicopter flight control through active blade pitch manipulation is presented by using piezoceramic directionally attached piezoelectric (DAP) torque plates mounted between the rotor shaft and the blade root.
Abstract: A new approach to helicopter flight control through active blade pitch manipulation is presented. By using piezoceramic directionally attached piezoelectric (DAP) torque plates mounted between the rotor shaft and the blade root, the pitch angle of the helicopter rotor blades may be adjusted as the blades sweep the azimuth. Analytical models based on classical laminated plate theory for steady torque-plate deflection are presented. To verify the models, a 1/12th-scale two-bladed experimental test article was constructed. The test article was Froude scaled with a 122 cm total diameter and a 5.5 cm chord. Static and dynamic testing showed that blade pitch deflections could be controlled from -4 through with good correlation between theory and experiment. Dynamic testing demonstrated that the first natural frequency in pitch was greater than 2.5 with a maximum power consumption of 194 mW under the most extreme conditions, thus making it feasible for control of collective, longitudinal and lateral cyclic. Whirl-stand testing at up to 600 RPM showed that the rotor could generate thrust coefficients ranging from -0.0046 through +0.014 with little sensitivity of blade deflection to increases in rotor speed.

21 citations

G. W. Gyatt1
01 Jul 1986
TL;DR: In this paper, VGs were used to alleviate the sensitivity of wind turbine rotors to leading edge roughness caused by bugs and drift caused by drift on the leading edge of wind turbines.
Abstract: Vortex generators (VGs) for a small (32 ft diameter) horizontal axis wind turbine, the Carter Model 25, have been developed and tested. Arrays of VGs in a counterrotating arrangement were tested on the inbound half-span, outboard half-span, and on the entire blade. VG pairs had their centerlines spaced at a distance of 15% of blade chord, with a spanwise width of 10% of blade chord. Each VG had a length/height ratio of 4, with a height of between 0.5% and 1.0% of the blade chord. Tests were made with roughness strips to determine whether VGs alleviated the sensitivity of some turbines to an accumulation of bugs and dirt on the leading edge. Field test data showed that VGs increased power output up to 20% at wind speeds above 10 m/s with only a small (less than 4%) performance penalty at lower speeds. The VGs on the outboard span of the blade were more effective than those on inner sections. For the case of full span coverage, the energy yearly output increased almost 6% at a site with a mean wind speed of 16 mph. The VGs did reduce the performance loss caused by leading edge roughness. An increase in blade pitch angle has an effect on the power curve similar to the addition of VGs. VGs alleviate the sensitivity of wind turbine rotors to leading edge roughness caused by bugs and drift.

21 citations

Journal ArticleDOI
TL;DR: In this paper, a series of experiments were conducted in a wind tunnel under different installation conditions to investigate the influence of blade pitch angle and axial distance on the performance of the counter-rotating type horizontal-axis tidal turbine (HATT).

21 citations


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