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US 6,972,498 B2Granted
Variable diameter wind turbine rotor blades
AssigneeGeneral Electric Company
InventorsPeter McKeich Jamieson, Chris Hornzee-Jones, Emilian M. Moroz, Ralph W. Blakemore
Life of this patent
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Abstract
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.
Claims26
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;
- and
- an 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.
1 more element
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;
- and
- after 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.
3 more elements
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;
- and
- a 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.
5 more elements
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;
- and
- a 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.
5 more elements
Dependencies are inferred from the claim text.