Blade pitch

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

Wind turbine having airfoils for blocking and directing wind and rotors with or without a central gap

Abstract: A wind turbine device (100) of increased efficiency is comprised of a set of fixed airfoils (104, 106) that direct wind into a rotor (102) having a plurality of blades (120, 122). The fixed airfoils may extend to the ground to increase the amount of wind directed into the rotor and may be manufactured from concrete. The rotor blades have a vented portion (114) near the axis of rotation that has been found to increase efficiency for certain blade geometries. For other blade geometries, increased efficiency is observed with no gap at the axis of rotation. The rotor may also be manufactured from composite materials to increase strength while decreasing the moment of inertia for the rotor.

Wind Turbine Wake Mitigation through Blade Pitch Offset

Abstract: The reduction in power output associated with complex turbine-wake interactions in wind farms necessitates the development of effective wake mitigation strategies. One approach to this end entails the downregulation of individual turbines from its maximum power point with the objective of optimizing the overall wind farm productivity. Downregulation via blade pitch offset has been of interest as a potential strategy, though the viability of this method is still not clear, especially in regard to its sensitivity to ambient turbulence. In this study, large-eddy simulations of a two-turbine arrangement, with the second turbine in the full wake of the first, were performed. The effects of varying the blade pitch angle of the upstream turbine on its wake characteristics, as well as the combined power of the two, were investigated. Of specific interest was the effect of turbulence intensity of the inflow on the efficacy of this method. Results showed enhanced wake recovery associated with pitching to stall, as opposed to pitching to feather, which delayed wake recovery. The increased wake recovery resulted in a noticeable increase in the power of the two-turbine configuration, only in conditions characterized by low turbulence in the incoming flow. Nevertheless, the low turbulence scenarios where the use of this method is favorable, are expected in realistic wind farms, suggesting its possible application for improved power generation.

Combining droop curve concepts with control systems for wind turbine active power control

Abstract: Wind energy is becoming a larger portion of the global energy portfolio, and wind penetration has increased dramatically in certain regions of the world This increasing wind penetration has driven the need for wind turbines to provide active power control (APC) services to the local utility grid, as wind turbines do not intrinsically provide frequency regulation services that are common with traditional generators Large scale wind turbines are typically decoupled from the utility grid via power electronics, which allows the turbines to synthesize APC commands via control of the generator torque and blade pitch commands Consequently, the APC services provided by a wind turbine can be more flexible than those provided by conventional generators This paper focuses on the development and implementation of both static and dynamic droop curves to measure grid frequency and output delta power reference signals to a novel power set point tracking control system The combined droop curve and power tracking controller is simulated and comparisons are made between simulations using various droop curve parameters and stochastic wind conditions The tradeoffs involved with aggressive response to frequency events are analyzed At the turbine level, simulations are performed to analyze induced structural loads At the grid level, simulations test a wind plant's response to a dip in grid frequency