Wind blade assembly and method for damping load or strain

• US 7,360,996 B2
• Filed: 12/07/2005
• Issued: 04/22/2008
• Est. Priority Date: 12/07/2005
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Driver, Howard D.
• Primary Examiner(s): Nguyen; Ninh H
• Application Number:
  US11/295,467
• Publication Number:
  US 20070128025A1
• Time in Patent Office: 867 Days
• Field of Search: 416/232, 416/226, 416/500, 416/61, 416/40, 188/266.7, 310/326
• US Class Current: 416/226
• CPC Class Codes: F03D 1/0658 Arrangements for fixing wind-engaging parts to a hub
• CPC Class Codes: F03D 7/02 the wind motors having rotation axis substantially parallel to the air flow entering the rotor
• CPC Class Codes: F05B 2220/709 Piezoelectric means
• CPC Class Codes: F05B 2260/75 the adjusting mechanism not using auxiliary power sources, e.g. servos
• CPC Class Codes: F05B 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y10S 416/50 Vibration damping features

Abstract

The transducers are incorporated in or laminated to wind blades and electrically connected to a self-powered electrical circuit. The transducers in combination with the self-powered electrical circuit improve the wind blades'"'"' response to changing wind conditions by reducing loads, at least until the turbines pitch axis system can alter the lie of the blades. Thus, when there is a change in wind conditions, the resultant twisting or bending of the wind blade during the impact of the wind (gust) on the wind blade is used to extract energy from the transducers. This energy is then transferred to the electrical circuit which in turn sends a signal back to the transducers to actuate them so as to resist the imposed load.

Claims

1. A wind turbine blade assembly comprising:

a plurality of blades mounted on a hub;

each said blade including a piezoelectric damping system comprising at least one transducer assembly one of incorporated in or mounted to said blade and at least one circuit located within or mounded to said blade and electrically connected to said at least one transducer assembly, said circuit including at least one storage element configured to store power extracted from at least one said transducer assembly;

wherein stored power is supplied back to at least one said transducer assembly, and said transducer assembly converts said electrical power to mechanical power, said mechanical power being adapted to actively stiffen said blade, and

wherein the blade includes a spar cap on forward and rearward facing surfaces thereof, and wherein at least one of the transducer assemblies is located at the forward facing spar can area.

2. A wind turbine blade assembly as in claim 1, wherein said piezoelectric damping system is a self-powered system, wherein all electrical power supplied to the at least one transducer assembly is derived from power extracted from mechanical deformation of the blade.

3. A wind turbine blade assembly as in claim 1, wherein at least one of the transducer assemblies is located adjacent to and generally parallel to the forward facing spar cap area.

4. A wind turbine blade assembly as in claim 1, wherein at least one said transducer assembly includes piezoelectric fibers.

5. A wind turbine blade assembly as in claim 1, further comprising an electrical power supply for augmenting said stored power.

6. A wind turbine blade assembly as in claim 1, further comprising a control computer operatively coupled to said circuit for sending commands to said circuit.

7. A wind turbine blade assembly as in claim 6, further comprising an electrical power supply for augmenting said stored power.

8. A wind turbine blade assembly as in claim 6, further comprising a wind sensor joined to said control computer to measure current wind conditions and provide such to said control computer;

and

sensors adapted to determine current configurations and speed of said blades and provide such to said control computer; and

wherein said control computer commands an actuator to reconfigure said blades for optimum performance under current wind conditions.

9. A method for damping load or strain in the blades of a wind turbine blade assembly comprising a plurality of blades mounted on a hub, comprising:

incorporating a piezoelectric damping system in or on each said blade, said piezoelectric damping system including at least one transducer assembly and at least one circuit electrically connected to said at least one transducer assembly, said circuit including at least one storage element configured to store power extracted from at least one said transducer assembly;

storing power extracted from at least one said transducer assembly with said storage element;

supplying said stored power back to at least one said transducer assembly; and

converting said electrical power to mechanical power to actively stiffen said blades,

wherein the blade includes a spar cap on forward and rearward facing surfaces thereof, and wherein at least one of the transducer assemblies is located adjacent to and generally parallel to the forward facing spar cap area.

10. A method as in claim 9, wherein said piezoelectric damping system is a self-powered system, wherein all electrical power supplied to the at least one transducer assembly is derived from power extracted from mechanical deformation of the blade.

11. A method as in claim 9, wherein a first said transducer assembly is located in or on the forward facing spar cap area and wherein a second said transducer assembly is located adjacent to and generally parallel to the forward facing spar cap area, and wherein said circuit stores energy derived from one of said transducer assemblies and supplies at least some of said energy to the other of said transducer assemblies.

12. A method as in claim 9, wherein at least one said transducer assembly includes piezoelectric fibers.

13. A method as in claim 9, further comprising augmenting said stored power with electrical energy from an electrical power supply.

14. A method as in claim 13, wherein said electrical power supply is located remote from said blade.

15. A method as in claim 9, further comprising sending commands to said circuit from a control computer located remote from said blade and operatively coupled to said circuit.

16. A method as in claim 15, further comprising augmenting said stored power with electrical energy from an electrical power supply.

17. A method as in claim 15, further comprising:

measuring current wind conditions and providing such to said control computer; and

determining current configurations and speed of said blades and providing such to said control computer;

wherein said control computer commands an actuator to reconfigure said blades for optimum performance under current wind conditions; and

wherein said supplying said stored power and converting said electrical power to mechanical power to actively stiffen said blade is terminated once said blades have been reconfigured.

18. A wind turbine blade assembly comprising:

a plurality of blades mounted on a hub;

each said blade including a piezoelectric damping system comprising at least one transducer assembly one of incorporated in or mounted to said blade and at least one circuit located within or mounded to said blade and electrically connected to said at least one transducer assembly, said circuit including at least one storage element configured to store power extracted from at least one said transducer assembly;

wherein stored power is supplied back to at least one said transducer assembly, and said transducer assembly converts said electrical power to mechanical power, said mechanical power being adapted to actively stiffen said blade,

further comprising a control computer operatively coupled to said circuit for sending commands to said circuit;

a wind sensor joined to said control computer to measure current wind conditions and provide such to said control computer,

sensors adapted to determine current configurations and speed of said blades and provide such to said control computer; and

wherein said control computer commands an actuator to reconfigure said blades for optimum performance under current wind conditions.

19. A method for damping load or strain in the blades of a wind turbine blade assembly comprising a plurality of blades mounted on a hub, comprising:

incorporating a piezoelectric damping system in or on each said blade, said piezoelectric damping system including at least one transducer assembly and at least one circuit electrically connected to said at least one transducer assembly, said circuit including at least one storage element configured to store power extracted from at least one said transducer assembly;

storing power extracted from at least one said transducer assembly with said storage element;

supplying said stored power back to at least one said transducer assembly; and

converting said electrical power to mechanical power to actively stiffen said blade;

further comprising sending commands to said circuit from a control computer located remote from said blade and operatively coupled to said circuit;

measuring current wind conditions and providing such to said control computer; and

determining current configurations and speed of said blades and providing such to said control computer;

wherein said control computer commands an actuator to reconfigure said blades for optimum performance under current wind conditions; and

wherein said supplying said stored power and converting said electrical power to mechanical power to actively stiffen said blade is terminated once said blades have been reconfigured.