Wind turbine and a blade for a wind turbine

Patent metadata

Field	Value
Publication number	US-9200614-B2
Application number	US-201013321455-A
Country	US
Kind code	B2
Filing date	May 19, 2010
Priority date	May 19, 2009
Publication date	Dec 1, 2015
Grant date	Dec 1, 2015

Abstract

A wind turbine with a rotor mounted on a hub section, wherein the rotor comprises a plurality of blades, at least one of which comprises a main blade section, which is optionally pitchable, and an auxiliary blade section mounted to the hub section. The auxiliary blade section is arranged in the area of a leading edge or of a trailing edge of the main blade, so that each blade is thereby provided with a leading edge slat or a trailing edge flap formed by the auxiliary blade section to increase the planform area of the blade and increase aerodynamic lift. A control method for a wind turbine controls a main blade section and an auxiliary blade section to provide different angles of attack to reduce undesired loads at sudden extreme changes of wind speed, e.g. during idling of the wind turbine. In a separate aspect, the invention provides a wind turbine having a blade with a non-pitchable leading edge slat, which extends at most 40% of the radius of the rotor in a longitudinal direction of the blade.

First claim

The invention claimed is:

1. A wind turbine, comprising:
a hub section configured to be rotatable about a hub axis; and
a rotor mounted on the hub section and including a plurality of blades, the rotor configured to be rotatable about a main axis of the wind turbine, and the hub axis being in fixed, co-axial alignment with the main axis of the wind turbine, wherein at least one of the blades of the rotor further comprises:
a main blade section having a leading edge and a trailing edge and configured to be driven by wind to rotate around the main axis, wherein the main blade section has a blunt trailing edge; and
at least first and second auxiliary blade sections configured to be driven by wind to rotate around the main axis, the second auxiliary blade section being separate from the first auxiliary blade section, wherein the at least first and second auxiliary blade sections are arranged in the area of at least one of the leading edge and trailing edge of the main blade section,
wherein the at least first and second auxiliary blade sections are directly mounted to the hub section and are configured to increase the planform area of the blade and increase aerodynamic lift, the first auxiliary blade section being configured to form a leading edge slat for the main blade section and the second auxiliary blade section being configured to form a trailing edge flap for the main blade section.

2. The wind turbine according to claim 1 , wherein the main blade portion has a length and the at least one auxiliary blade section extends along a portion of the length of the main blade section.

3. The wind turbine according to claim 1 , wherein the thickness of the blunt trailing edge is at least 2% of the chord of the main blade section.

4. A wind turbine, comprising:
a hub section configured to be rotatable about a hub axis; and
a rotor mounted on the hub section and including a plurality of blades, the rotor configured to be rotatable about a main axis of the wind turbine, and the hub axis being in fixed, co-axial alignment with the main axis of the wind turbine, wherein at least one of the blades of the rotor further comprises:
a main blade section having a leading edge and a trailing edge and configured to be driven by wind to rotate around the main axis; and
at least one auxiliary blade section configured to be driven by wind to rotate around the main axis, wherein the at least one auxiliary blade section is arranged in the area of at least one of the leading edge and trailing edge of the main blade section,
wherein the at least one auxiliary blade section is directly mounted to the hub section and is configured to form a leading edge slat or a trailing edge flap for the main blade section to increase the planform area of the blade and increase aerodynamic lift, and
wherein the main blade section forms at least a portion of the outer surface of the at least one blade along substantially the full length of the at least one auxiliary blade section.

5. The wind turbine according to claim 4 , wherein no portion of the at least one auxiliary blade section fully encompasses the main blade section.

6. The wind turbine according to claim 4 , wherein no portion of the main blade section lies within the perimeter of the at least one auxiliary blade section.

7. The wind turbine according to claim 4 , wherein the at least one auxiliary blade section is mounted to the hub section in a non-pitchable manner.

8. The wind turbine according to claim 4 , wherein the at least one auxiliary blade section extends at most 40% of the radius of the rotor in a longitudinal direction of the blades.

9. The wind turbine according to claim 8 , wherein the leading edge slat or trailing edge flap is provided closer to a hub portion of the rotor than to a tip portion thereof.

10. The wind turbine according to claim 8 , wherein each auxiliary blade section extends at most 30% of the radius of the rotor in a longitudinal direction of a respective blade.

11. The wind turbine according to claim 10 , wherein each auxiliary blade section extends at most 20% of the radius of the rotor in a longitudinal direction of a respective blade.

12. The wind turbine according to claim 4 , wherein main blade section has one and only one leading edge slat and/or one and only one trailing edge flap.

13. The wind turbine according to claim 4 , wherein a chord line of each of the at least one leading edge slats and trailing edge flaps is vertically offset from a chord line of a respective one of the main blade section, when seen in cross section.

14. The wind turbine according to claim 4 , further comprising vortex-generating structure on a suction side of the at least one auxiliary blade section.

15. The wind turbine according to claim 4 , wherein the at least one auxiliary blade section forms the leading edge slat, and wherein a trailing edge of the leading edge slat is arranged at a distance from a leading edge of the main blade section so as to thereby provide a flow passage from a pressure side of the leading edge slat to a suction side of the main blade section.

16. The wind turbine according to claim 4 , wherein the at least one auxiliary blade section forms the trailing edge flap, and wherein a leading edge of the trailing edge flap is arranged at a distance from a trailing edge of the main blade section so as to thereby provide a flow passage from a pressure side of the main blade section to a suction side of the trailing edge flap.

17. The wind turbine according to claim 4 , wherein the at least one auxiliary blade section is provided only at a part of the main blade section which has a thickness-to-chord ratio of at least 30%.

18. A method of controlling operation of a wind turbine having a hub section rotatable about a hub axis, and a rotor mounted on the hub section and including a plurality of blades rotatable around a main axis of the wind turbine, at least one of the blades of the rotor comprising a pitchable main blade section and an auxiliary blade section directly mounted to the hub section, the main and auxiliary blade section arranged to be driven by wind to rotate around the main axis, the auxiliary blade section configured to form a leading edge slat or a trailing edge flap for the main blade section, the method comprising:
arranging the pitchable main blade sections with a first angle of attack with respect to oncoming wind; and
arranging the auxiliary blade section with a second angle of attack different from the first angle of attack with respect to the oncoming wind.

19. The method according to claim 18 , further comprising achieving aerodynamic stall at the first angle of attack of the pitchable main blade section.

20. The method according to claim 18 , further comprising setting the first angle of attack of the main blade section such that essentially no lift is conferred on the main blade section during idling operation of the wind turbine.

21. The method according to claim 20 , further comprising setting the second angle of attack of the auxiliary blade section so as to provide an aerodynamic lift on the auxiliary blade section during idling operation of the wind turbine.

22. The method according to claim 20 , further comprising setting the second angle of attack of the auxiliary blade section such that essentially no lift is conferred on the auxiliary blade section during idling operation of the wind turbine.

23. The method according to claim 18 , further comprising setting the first an

Assignees

• Godsk Kristian Balschmidt
• Vestas Wind Sys As

Inventors

• Godsk Kristian Balschmidt

Classifications

• F05B2240/301

  Cross-section characteristics · CPC title

• F05B2240/202

  with adjustable area of intercepted fluid · CPC title

• F03D1/0658

  Arrangements for fixing wind-engaging parts to a hub · CPC title

• F03D1/0608 Primary

  characterised by their aerodynamic shape · CPC title

• F03D1/06

  Rotors · CPC title