초록 ▼

A system and method for changing wind turbine rotor diameters to meet changing wind speeds and control system loads is disclosed. The rotor blades on the wind turbine are able to adjust length by extensions nested within or containing the base blade. The blades can have more than one extension in a

A system and method for changing wind turbine rotor diameters to meet changing wind speeds and control system loads is disclosed. The rotor blades on the wind turbine are able to adjust length by extensions nested within or containing the base blade. The blades can have more than one extension in a variety of configurations. A cable winching system, a hydraulic system, a pneumatic system, inflatable or elastic extensions, and a spring-loaded jack knife deployment are some of the methods of adjustment. The extension is also protected from lightning by a grounding system.

대표청구항 ▼

1. A wind turbine, comprising:a center hub;a plurality of aerofoil rotor blades arranged around the center hub, each aerofoil rotor blade being adjustable in length and being adjustable in pitch angle; andan electrical control system to control the length and pitch angle of the plurality of aerofoil

1. A wind turbine, comprising:a center hub;a plurality of aerofoil rotor blades arranged around the center hub, each aerofoil rotor blade being adjustable in length and being adjustable in pitch angle; andan electrical control system to control the length and pitch angle of the plurality of aerofoil rotor blades, the electrical control system to command the aerofoil rotor blades to a first pitch angle when the aerofoil rotor blades are at a maximum length, the electrical control system to command the aerofoil rotor blades to a second pitch angle greater than the first pitch angle if a threshold is exceeded, the electrical control system to command a reduction in length of the aerofoil rotor blades after the command to the second pitch angle.2. The wind turbine of claim 1, wherein the first pitch angle is a minimum pitch angle for the plurality of aerofoil rotor blades.3. The wind turbine of claim 1, wherein each of the plurality of airfoil rotor blades comprises:a first aerofoil rotor blade portion attached to the center hub; anda second aerofoil rotor blade portion, the second aerofoil blade portion being movable into and out of the first aerofoil rotor blade portion to adjust the length of the aerofoil rotor blade.4. The wind turbine of claim 3, wherein the second aerofoil rotor blade portion is nested at least partially inside the first aerofoil rotor blade portion.5. The wind turbine of claim 3, wherein the second aerofoil rotor blade portion is made of a carbon compound.6. The wind turbine of claim 3, wherein the second aerofoil rotor blade portion is made of a glass epoxy.7. The wind turbine of claim 3, wherein each aerofoil rotor blade includes one or more spark gaps to electrically connect the second aerofoil rotor blade portion to a cable system to expand and retract the aerofoil rotor blade.8. The wind turbine of claim 7, wherein each of the plurality of aerofoil rotor blades includes one or more spark gaps to electrically connect the cable system to the center hub.9. The wind turbine of claim 3, wherein each of the plurality of aerofoil rotor blades includes an electrically conductive track on the first aerofoil rotor blade portion and a sliding contact on the second aerofoil rotor blade portion to electrically connect the second aerofoil rotor blade portion to the electrically conductive track.10. The wind turbine of claim 3, wherein each of the plurality of airfoil rotor blades further comprises a third aerofoil blade portion, the third aerofoil blade portion being movable to adjust the length of the aerofoil rotor blade.11. The wind turbine of claim 10, wherein the second aerofoil blade portion is adjustable independently from the third aerofoil blade portion.12. The wind turbine of claims 1, wherein the electrical control system further controls a yaw mechanism to control the direction of the wind turbine.13. The wind turbine of claims 12, wherein the electrical control system further controls rotational speed of the wind turbine.14. The wind turbine of claim 1, wherein the threshold is a maximum wind speed.15. The wind turbine of claim 1, wherein the threshold is a maximum amount of power generated by the wind turbine.16. A method comprising:extending a first aerofoil rotor blade of a plurality of aerofoil rotor blades of a wind turbine to a maximum length for the aerofoil rotor blade;adjusting a pitch angle of the first aerofoil rotor blade to a minimum pitch angle for the aerofoil rotor;detecting an indication to shorten the length of the first aerofoil rotor blade while the first aerofoil rotor blade is at the maximum length;in response to detecting the indication to shorten the length of the first aerofoil rotor blade, adjusting the pitch angle of the first aerofoil rotor blade to another pitch angle greater than the minimum pitch angle; andafter commencing the adjustment of the pitch angle of the first aerofoil rotor blade, shortening the first aerofoil rotor blade to a length that is less than the maximum length.17. The method of claim 16, wherein detecting the indication to shorten the length of the first aerofoil rotor blade comprises detecting a wind speed above a threshold.18. The method of claim 16, wherein detecting the indication to shorten the length of the first aerofoil rotor blade comprises detecting a level of power generated by the wind turbine above a threshold.19. The method of claim 16, wherein the first aerofoil rotor blade comprises a first section coupled with a center hub and a second section movably coupled with the first section, and wherein adjusting the length of the first aerofoil rotor blade comprises moving the second section towards or away from the center hub.20. The method of claim 19, wherein the first aerofoil rotor blade further comprises a third section movably coupled with the second section, and wherein adjusting the length of the first aerofoil rotor blade further comprises moving the third section towards or away from the center hub.21. The method of claim 20, wherein the second section and the third section are adjusted independently.22. A wind turbine, comprising a variable diameter rotor having:a center hub;a first set of aerofoil rotor blades arranged around the center hub;a first set of aerofoil rotor blade extensions nested at least partially inside the first set of aerofoil rotor blades; anda second set of aerofoil rotor blade extensions nested at least partially in the first set of aerofoil rotor blades or the first set of aerofoil rotor blade extensions;wherein the first set of blade extensions and the second set of blade extensions are capable of extending an amount less than or equal to the length of the first set of blades by protracting from the first set of blades; wherein the first set of blades are attached to the center hub, the first set of blade extensions protracting from an end of the first set of blades opposite the hub, and the first set of blade extensions being nested at least partially in the second set of blade extensions; and wherein the second set of blade extensions are connected to the first set of blades by the first set of blade extensions such that, when the first set of blade extensions is retracted, the first set of blade extensions nest partially in the first set of blades and partially in the second set of blade extensions.23. The wind turbine of claim 22, further comprising a first set of seal strips between the second set of blade extensions and the first set of blade extensions.24. The wind turbine of claim 23, further including a second set of seal strips between the first set of blade extensions and the first set of blades.25. A wind turbine, comprising a variable diameter rotor having:a center hub;a first set of aerofoil rotor blades arranged around the center hub;a first set of aerofoil rotor blade extensions nested at least partially inside the first set of aerofoil rotor blades; anda second set of aerofoil rotor blade extensions nested at least partially in the first set of aerofoil rotor blades or the first set of aerofoil rotor blade extensions;wherein the first set of blade extensions and the second set of blade extensions are capable of extending an amount less than or equal to the length of the first set of blades by protracting from the first set of blades; wherein the first set of blade extensions are attached to the center hub, with the first set of blade extensions protracting from an end of the first set of blades closest to the center hub; and wherein the second set of blade extensions are nested within the first set of blades at an end opposite the end that is attached to the first set of blade extensions, so that both sets of blade extensions, when completely retracted, are nested within the first set of blades.26. The wind turbine of claim 25, wherein the second set of blade extensions are nested within the first set of blades at an end opposite the end that is attached to the first set of blade extensions, so that both sets of blade extensions, when completely retracted, are partially nested within the first set of blades.