A wind turbine with improved response to wind conditions is provided. Blade flap angle motion is accompanied by a change in pitch angle by an amount defining a pitch/flap coupling ratio. The coupling ratio is non-constant as a function of a flap angle and is preferably a substantially continuous, non-linear function of flap angle. The non-constant coupling ratio can be provided by mechanical systems such as a series of linkages or by configuring electronic or other control systems and/or angle sensors. A link with a movable proximal end advantageously is part of the mechanical system. The system can provide relatively large coupling ratios and relatively large rates of coupling ratio changes especially for near-feather pitches and low flap angles.
FIELD OF THE INVENTION
This invention was made with Government support under the National Renewable Energy Laboratory, under Contract Number ZAM-7-13220-29 awarded by the Department of Energy. The Government has certain rights in this invention. The present invention is directed to a wind turbine and particularly to a device and method for controlling pitch and flap angles of the wind turbine.