Wind turbine with deployable air deflectors
An apparatus and system for compensating for various load situations in a turbine includes the use of one or more deployable devices configured to extend an air deflector outwardly from a surface of a rotor blade. The air deflector may subsequently be retracted into the rotor blade once the load falls below a certain threshold. Mechanisms for extending and retracting the air deflector may include pneumatic, hydraulic and/or electromechanical devices. Air deflectors are generally configured to modify the air flow around the rotor blade to increase or decrease power generation, or reduce loads so that the risk of potential damage to components of the wind turbine is minimized. Deflectors may be positioned at various chordwise stations including leading-edge, mid-chord, and trailing-edge locations on the upper and lower surfaces at spanwise positions. Accordingly, a plurality of devices can be actuated to aerodynamically control rotor performance and loads based on wind conditions.
1. A method comprising:
determining, by a control unit having at least one processor, a load on a rotor blade of a power generating turbine, wherein the rotor blade includes a plurality of air deflectors, wherein each of the plurality of air deflectors is configured to protrude from a surface of the rotor blade when deployed, and wherein a top surface of each of the plurality of air deflectors, when in a de-activated state, forms a portion of the surface of the rotor blade;
identifying a set of one or more air deflectors to activate based on the determined load; and
selectively, by the control unit, activating the set of one or more air deflectors, wherein the set of one or more air deflectors is a proper subset of the plurality of air deflectors, and
wherein activating the set of one or more air deflectors includes raising an entire top surface of the set of one or more air deflectors above a surface of a remainder of the rotor blade.
2. The method of claim 1 , wherein determining, by the control unit, by the control unit, the load on the rotor blade includes determining whether to increase power generation of the turbine; and
in response to determining to increase the power generation, selectively activating an air deflector located at a trailing edge of a lower surface of the rotor blade.
3. The method of claim 2 , wherein determining whether to increase power generation of the power generating turbine includes determining whether a current amount of power being generated is below a specified power generation threshold.
4. The method of claim 2 , wherein the air deflector is located between 51% and 100% of the distance between a leading edge of the at least one rotor blade and a trailing edge of the at least one rotor blade.
5. The method of claim 2 , wherein deploying the air deflector includes deploying the air deflector to a height on an order of magnitude of the boundary-layer thickness of the local blade section.
6. The method of claim 2 , further comprising determining a height of the air deflector that results in a specified level of load change, wherein deploying the air deflector includes deploying the air deflector to the determined height.
7. The method of claim 1 , wherein determining, by the control unit, the load on the rotor blade includes detecting a threshold amount of edgewise resonance and wherein the method further includes:
in response to detecting the threshold amount of edgewise resonance, selectively activating one or more of: a lower surface trailing edge air deflector, an upper surface mid-chord air deflector and a lower surface mid-chord air deflector.
8. The method of claim 1 , wherein determining, by the control unit, the load on the rotor blade includes determining that the load exceeds a threshold load and wherein the method further includes:
in response to determining that the load exceeds the threshold load, selectively activating trailing, mid-chord and leading edge air deflectors on both the upper and lower surfaces of the rotor blade.
9. A rotor blade comprising:
an upper surface;
a lower surface; and
a plurality of selectively and independently deployable air deflectors located on at least one of the upper surface and the lower surface, wherein each of the deployable air deflectors is configured to extend from at least one of the upper surface and the lower surface when deployed.
10. The rotor blade of claim 9 , wherein a first set of one or more selectively deployable air deflectors is located at a trailing edge of the rotor blade and a second set of one or more selectively deployable air deflectors is located at a mid-chord region of the rotor blade.
11. The rotor blade of claim 9 , wherein the selectively deployable air deflectors are embedded in the rotor blade in an undeployed position and wherein the selective deployable air deflectors extend from the rotor blade in a deployed position.
12. The rotor blade of claim 9 , wherein a first set of one or more selectively deployable air deflectors is located at a mid-chord region of the rotor blade and a second set of one or more selectively deployable air deflectors is located at a leading edge of the rotor blade.
13. The rotor blade of claim 9 , further comprising a control module configured to control the deployment of the air deflectors.
14. The rotor blade of claim 13 , wherein the control module is further configured to:
determine a load condition on the rotor blade;
determine whether to deploy one or more of the selectively deployable air deflectors based on the determined load condition; and
in response to determining to deploy one or more of the selectively deployable air deflectors, identifying a set of selectively deployable air deflectors to deploy based on the determined load condition.
15. The rotor blade of claim 14 , wherein the load condition includes an asymmetric load and wherein the identified set of air deflectors includes a first set of air deflectors located on an upper surface trailing edge of the rotor blade and a second set of air deflectors located on a lower surface trailing edge of the rotor blade.
16. The rotor blade of claim 14 , wherein the control module is further configured to determine a deployment height of the identified set of air deflectors.
17. The rotor blade of claim 9 , wherein the rotor blade includes a first set of selectively deployable air deflectors located at a leading edge of the rotor blade, a second set of selectively deployable air deflectors located at a trailing edge of the rotor blade and a third set of selectively deployable air deflectors located at a mid-chord region of the rotor blade.
18. A method comprising:
identifying a set of one or more air deflectors to activate based on the determined load, wherein the set is identified from a plurality of air deflectors, wherein the plurality of air deflectors are configured to extend from a surface of a rotor blade when deployed; and
selectively activating the set of one or more air deflectors, wherein the set of one or more air deflectors is a proper subset of the plurality of air deflectors, wherein activating the set of one or more air deflectors includes extending the set of one or more air deflectors from an interior region of the rotor blade to above the surface of the rotor blade.
19. The method of claim 18 , wherein identifying the set of one or more air deflectors is performed based on determining at least one of: a rotor torque and a rotor speed associated with the rotor blade.
20. The method of claim 18 , wherein identifying the set of one or more air deflectors is performed based on determining a rotor thrust associated with the rotor blade.