Wind turbine blade control method

Patent metadata

Field	Value
Publication number	US-9909562-B2
Application number	US-201214365375-A
Country	US
Kind code	B2
Filing date	Dec 5, 2012
Priority date	Dec 15, 2011
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A control method for a wind turbine, in particular for a wind turbine blade is described. The control method makes use of the blade mode shapes, or natural vibration shapes, of the blade to detect the excitement level of the blade natural vibrations, and controls active lift devices on the blade in an effort to reduce the excitement levels, to reduce loading in the blade and the overall wind turbine structure. There is also provided a method of designing a wind turbine blade for use in such a method.

First claim

The invention claimed is:

1. A method of controlling a wind turbine blade during operation of a wind turbine to reduce root moments of the blade, the blade having a tip end and a root end, the method comprising the steps of:
identifying an excited mode shape of the wind turbine blade;
adjusting at least one active lift device provided on said blade to reduce a modal vibration of said blade during operation of said wind turbine, wherein said step of adjusting is based on said identified excited mode shape, wherein the modal vibration of said blade is substantially provided by a combination of the excitement of a mode 1 shape and the excitement of a mode 2 shape of said blade; and
providing first and second active lift devices on the blade, said first and second active lift devices selectively actuatable to control said mode 1 and mode 2 shapes, wherein the location of said first and second active lift devices on the blade are selected to provide minimum interference between the mode 1 and mode 2 shapes as the active lift devices are actuated.

2. The method of claim 1 , wherein said step of identifying an excited mode shape comprises:
measuring a deflection of said wind turbine blade, and
comparing said measured deflection with at least one known mode shape of said wind turbine blade to determine an excitement level for said at least one mode shape,
wherein said step of adjusting comprises actuating said at least one active lift device based on said excitement level to reduce the magnitude of said excited mode shape, to reduce a modal vibration of said blade.

3. The method of claim 1 , wherein the modal vibration of said blade is based at least on the excitement of a mode 1 shape of said blade, and wherein the method comprises the steps of:
providing at least a first active lift device at a location towards the tip end of said blade; and
actuating said at least a first active lift device to control the excitement level of said mode 1 shape, using the excitement co-ordinate of said mode 1 shape as an input to said at least a first active lift device.

4. The method of claim 1 , wherein the method comprises the steps of:
providing a first active lift device at a location along the length of the blade between the node of said mode 2 shape and the tip end of the blade; and
providing a second active lift device at a location along the length of the blade between the node of said mode 2 shape and the root end of the blade.

5. The method of claim 1 , wherein said step of comparing comprises analyzing said measured deflection to determine an excitement value for the mode 1 shape of the blade and an excitement value for the mode 2 shape of the blade, and wherein said step of actuating comprises actuating said first active lift device and said second active lift device based on a combination of the excitement values for the mode 1 and mode 2 shapes of the blade.

6. The method of claim 1 , wherein the method comprises the step of:
comparing said excitement value for the mode 1 shape of the blade with a threshold value, and
when said mode 1 excitement value exceeds said threshold value, performing a mode 1 control operation, and
when said mode 1 excitement value is less than said threshold value, performing a mode 1 control operation and a mode 2 control operation.

7. The method of claim 6 , wherein said step of performing a mode 1 control operation comprises actuating said active lift devices to reduce the magnitude of the excited blade mode 1 shape.

8. The method of claim 6 , wherein said step of performing a mode 2 control operation comprises actuating said active lift devices to reduce the magnitude of the excited blade mode 2 shape.

9. The method of claim 1 , wherein the method comprises the steps of:
controlling the mode 1 shape of said blade by actuating said first and second active lift devices in the same direction; and
controlling the mode 2 shape of said blade by actuating said first and second active lift devices in opposite directions.

10. A method of designing a wind turbine blade, comprising:
providing a wind turbine blade;
performing a modal analysis of said wind turbine blade to determine the mode 1 and mode 2 shapes of the wind turbine blade; and
positioning at least one active lift device on said wind turbine blade based on said at least one determined mode shape, such that an excitement level of said at least one determined mode shape can be controlled by actuation of said active lift device;
wherein a location of said at least one active lift device on said wind turbine blade is selected to provide minimum interference between the mode 1 and mode 2 shapes as said at least one active lift device is actuated.

11. The method of claim 10 , wherein said step of positioning comprises providing said active lift device on said wind turbine blade at a location along the length of the blade corresponding to the node of said mode 2 shape, such that said active lift device is operable to control an excitement level of said mode 1 shape without affecting an excitement level of said mode 2 shape.

12. The method of claim 10 , wherein said step of positioning comprises providing a first active lift device and a second active lift device on said wind turbine blade,
wherein said first active lift device is provided at a first location along the length of the blade and said second active lift device is provided at a second location along the length of the blade,
wherein the location of said first and second active lift devices on the blade are selected to provide minimum cross-talk between the mode 1 and mode 2 shapes as the active lift devices are actuated.

13. The method of claim 12 , wherein said first active lift device is provided at a location along the length of the blade between the node of said mode 2 shape and the tip end of the blade, and wherein said second active lift device is provided at a location along the length of the blade between the node of said mode 2 shape and the root end of the blade, such that the active lift devices are operable to control excitement levels of said mode 1 shape and said mode 2 shape.

14. A wind turbine blade designed according to the method of claim 10 .

Assignees

• Lm Wp Patent Holdings As
• Lm Wp Patent Holding As

Inventors

• Baek Peter
• Andersen Christian Frank
• Slot Mark Olaf
• Skovby Casper
• Bojesen Simon Berg
• Ravn Morten
• Klitgaard Michael

Classifications

• F03D7/045

  with model-based controls · CPC title

• Y02E10/721

  Cross-Sectional Technologies · mapped topic

• F03D7/043

  characterised by the type of control logic · CPC title

• F03D7/0296

  to prevent, counteract or reduce noise emissions · CPC title

• Y02E10/723

  Cross-Sectional Technologies · mapped topic