Blade pitch

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

Aircraft engine unducted fan blade pitch control system

Abstract: An electric motor driven blade pitch varying system for the fan blades of an unducted fan type aircraft gas turbine engine utilizes permanent magnet alternating current motors located in the oil sump region of the engine. An alternator driven by the engine generates unregulated variable frequency, variable amplitude power which is rectified and placed on a DC bus. Controlled inverters convert the DC power on the bus to appropriate AC power for the motors. The system incorporates redundancy without significant weight penalty by providing alternators and motors dividing into two independent operating sections on common shafts. Separate electronic circuits are provided to supply power for each sectionalized motor or to rectify power from each alternator section. A common power bus may be used to couple the multiple motors and alternators. The common bus may alternatively receive power from tbe aircraft 400 Hz system or from on-board batteries.

Numerical simulation of wind turbine blade-tower interaction

Abstract: Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface (AMI) method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes (RANS) which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory (NREL) phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds (5, 10, 15, and 25 m/s) at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.

Wind turbine load reduction by rejecting the periodic load disturbances

Abstract: For the cost per kilowatt hour to be decreased, the trend in offshore wind turbines is to increase the rotor diameter as much as possible. The increasing dimensions have led to a relative increase of the loads on the wind turbine structure; thus, it is necessary to react to disturbances in a more detailed way, e.g. each blade separately. The disturbances acting on an individual wind turbine blade are to a large extent deterministic; for instance, tower shadow, wind shear, yawed error and gravity are depending on the rotational speed and azimuth angle and will change slowly over time. This paper aims to contribute to the development of individually pitch-controlled blades by proposing a lifted repetitive controller that can reject these periodic load disturbances for modern fixed-speed wind turbines and modern variable-speed wind turbines operating above-rated. The performance of the repetitive control method is evaluated on the UPWIND 5 MW wind turbine model and compared with typical individual pitch control. Simulation results indicate that for relatively slow changing periodic wind disturbances, this lifted repetitive control method can significantly reduce the vibrations in the wind turbine structure with considerably less high-frequent control action. Copyright © 2012 John Wiley & Sons, Ltd.

Pitch angle control of variable low rated speed wind turbine using fuzzy logic controller

Abstract: Pitch angle control of wind turbine has been used widely to reduce torque and output power variation in high rated wind speed areas It is a challenge to maximize available energy in the low rated wind speed areas In this paper, a wind turbine prototype with a pitch angle control based on fuzzy logic to maximize the output power is built and demonstrated In the varying low rated wind speed of 4-6 m/s, the use of fuzzy logic controller can maximize the average output power of 145 watt compared to 140 watt at a fixed pitch angle of the blade Implementation of pitch angle fuzzy logic-based control to the wind turbine is suitable for the low rated wind speed areas

Rotor pitch control method and apparatus for parking wind turbine

Abstract: A wind turbine is configurable with at least one blade is pitched to provide relatively high sensitivity to wind direction or sheer so as to perform a rudder function which moves the blades such that the vertical plane defined by the blade ends is substantially parallel to the wind direction. In one aspect, the wind turbine has at least two different blades having two different blade pitches. In one embodiment, the rudder action configures a two bladed wind turbine such that a non-rudder blade, having a pitch different from the rudder blade, has its free end pointing substantially directly into the wind, providing relatively low cross-sectional resistance to the wind and accordingly relatively low load.