Wind Turbine Blade And Method For Controlling The Load On A Blade

Abstract

A wind turbine blade includes a blade body and lift-regulating mechanism adapted for movement in relation to the blade body by at least one actuation mechanism controlled by an actuation controller. The actuation controller controls a setting of the lift-regulating mechanism based on an input from a sensor, and the sensor is a force sensor adapted for sensing a force from a wind flow acting on the lift-regulating mechanism, whereby a wind turbine blade with fast-responding lift-regulating mechanism is provided.

1 . A wind turbine blade comprising a blade body and a lift-regulator adapted for movement in relation to the blade body by at least one actuator controlled by an actuation controller, wherein the actuation controller controls a setting of the lift-regulator based on an input from a sensor,
 wherein the sensor is a force sensor adapted for sensing a force from a wind flow acting on the lift-regulator.   
     
     
         2 . The wind turbine blade according to  claim 1 , wherein the sensor is a strain or pressure gauge. 
     
     
         3 . The wind turbine blade according to  claim 1 , wherein the sensor is a piezo-electric array. 
     
     
         4 . The wind turbine blade according to  claim 1 , wherein the lift-regulator is a trailing edge flap. 
     
     
         5 . The wind turbine blade according to  claim 4 , wherein the flap comprises a plurality of individually movable flap segments. 
     
     
         6 . The wind turbine blade according to  claim 5 , wherein the flap segments are arranged side-by-side in a longitudinal direction of the blade. 
     
     
         7 . The wind turbine blade according to  claim 1 , wherein the lift-regulator is arranged along a substantial part of a length of the blade. 
     
     
         8 . The wind turbine blade according to  claim 1 , wherein the lift-regulator is adapted for providing a substantially continuous shape change in a longitudinal direction of the blade. 
     
     
         9 . The wind turbine blade according to  claim 1 , wherein the actuation controller is adapted for receiving data relating to one or more of the following parameters:
 wind speed,   wind shear,   speed of wind flow locally in at least one position on one or more blades,   blade vibrations,   weather conditions,   power consumption of the actuator,   actual blade load, and   blade load history.   
     
     
         10 . The wind turbine blade according to  claim 1 , wherein the lift-regulator is connected to the blade by means of at least one hinge allowing the lift-regulator to move in relation to the blade and wherein the sensor is adapted to sense a torque acting on the lift-regulator around the hinge. 
     
     
         11 . A wind turbine comprising a wind turbine blade according to  claim 1 . 
     
     
         12 . The wind turbine according to  claim 11 , wherein the actuation controller of one blade is adapted for receiving input from a controller of another blade of the wind turbine. 
     
     
         13 . The wind turbine according to  claim 11 , wherein the wind turbine comprises a pitch controller adapted for receiving input from an actuation controller of one or more of the blades. 
     
     
         14 . A method for regulating lift of a wind turbine blade, wherein the blade comprises a blade body and a lift-regulator adapted for movement in relation to the blade body by at least one actuator and wherein the method comprises the steps of
 monitoring a force from a wind flow acting on the lift-regulator by means of at least one sensor,   providing an output signal from the sensor in correspondence to the force, and   controlling a setting of the lift-regulator in relation to the blade body on a basis of the output signal from the sensor.   
     
     
         15 . The method according to  claim 14 , wherein the method further comprises the steps of
 delivering the output signal from the sensor to an actuation controller, and   controlling a setting of the lift-regulator in relation to the blade on the basis of an input from the actuation controller, wherein said input is established on the basis of the output signal from the force sensor.   
     
     
         16 . The method according to  claim 15 , wherein the method further comprises the steps of
 providing a set-point signal to the actuation controller from a wind turbine main controller, and   controlling the setting of the lift-regulator directly or partly on a basis of a difference between the output signal from the sensor and the set-point signal.   
     
     
         17 . The method according to  claim 14 , wherein the method further comprises the steps of
 delivering the output signal from the sensor to a wind turbine main controller, and   controlling a setting of the lift-regulator in relation to the blade on the basis of an input from the main controller, wherein said input is established on the basis of the output signal from the force sensor.   
     
     
         18 . The method according to  claim 14 , wherein the method further comprises the step of controlling a setting of a first lift-regulator located on a first blade, on the basis of an input from a first actuation controller, wherein said input is additionally established on the basis of an output signal from a second actuation controller, wherein said second actuation controller controls a second lift-regulator located on a further blade. 
     
     
         19 . The method according to  claim 14 , wherein the blade comprises more than one lift-regulator each controlled by an independent actuation controller and wherein the method further comprises the step of checking an overall consistency of at least two of the independent actuation controllers to ensure that the lift-regulators are coordinating reactions. 
     
     
         20 . A method for controlling the load on a wind turbine blade, said method comprising the steps of:
 providing a lift-regulator adjustable by an actuator,   providing a controller for controlling the actuator based on input from a sensor, and   
       employing a control strategy for adjusting the lift-regulator based on input from the sensor regarding loading of the lift-regulator.