Floating wind turbine blade pitch adjustment for wave activity

Patent metadata

Field	Value
Publication number	US-2021123414-A1
Application number	US-201916664567-A
Country	US
Kind code	A1
Filing date	Oct 25, 2019
Priority date	Oct 25, 2019
Publication date	Apr 29, 2021
Grant date	—

Abstract

Provided is a method, computing system, and computer program product for reducing floating wind turbine loads induced by ocean waves by adjusting a blade pitch angle of at least one rotor blade of a floating wind turbine to minimize a moment imbalance at a platform top of the floating wind turbine caused by ocean wave activity.

First claim

1 . A method for reducing floating wind turbine loads induced by ocean waves, the method comprising:
adjusting a blade pitch angle of at least one rotor blade of a floating wind turbine to minimize a moment imbalance at a platform top of a floating wind turbine caused by ocean wave activity.

2 . The method of claim 1 , further comprising calculating an error signal based on the moment imbalance measured between a tower bottom moment and a thrust moment.

3 . The method of claim 2 , wherein the tower bottom moment is a moment at a platform top of the floating wind turbine as a result of environmental loads, and the thrust moment is a moment defined by a thrust force of rotor blades of the floating wind turbine measured at a location on the shaft of the floating turbine proximate the platform top.

4 . The method of claim 2 , further comprising: filtering the error signal using a bandpass filter in a frequency range attributable to ocean wave activity to obtain a filtered error signal.

5 . The method of claim 4 , wherein the filtering isolates wave excitation frequencies from the error signal that are in the frequency range defined by an ocean wave spectrum.

6 . The method of claim 4 , wherein the blade pitch angle is adjusted according to a pitch offset signal converted from the filtered error signal.

7 . The method of claim 6 , wherein the pitch offset signal is converted from the filtered error signal by calculating a difference between an actual pitch angle value of at least one rotor blade and a desired blade pitch angle of at least one rotor blade, wherein the difference defines the pitch offset signal.

8 . A method for reducing loads induced by ocean waves on a floating wind turbine, the method comprising:
calculating, by a processor of a computing system, an error signal defined by a moment imbalance between a tower bottom moment and a thrust moment of the floating wind turbine; filtering, by the processor, the error signal in a frequency range attributable to ocean wave activity to eliminate frequencies contributing to the error signal that are not attributable to ocean wave activity, resulting in a filtered error signal; converting, by the processor, the filtered error signal to a pitch offset signal; and adjusting, by the processor, a blade pitch angle of at least one rotor blade of the floating wind turbine according to the pitch offset signal.

9 . The method of claim 8 , wherein the tower bottom moment is a moment at a platform top of the floating wind turbine as a result of environmental loads, and the thrust moment is a moment defined by a thrust force of rotor blades of the floating wind turbine measured at a location at a tower section of the floating turbine proximate the platform top.

10 . The method of claim 8 , wherein the error signal comprises frequencies attributable to one or more of: turbulence due to wind above sea level, ocean wave activity, ocean current variability, vortex induced vibrations, structural resonances, electrical grid phenomena, and normal turbine operations.

11 . The method of claim 11 , wherein the error signal is filtered using a bandpass filter tuned to filter out frequencies above or below the frequency range attributable to ocean wave activity.

12 . The method of claim 11 , wherein the frequency range attributable to ocean wave activity is defined by an ocean wave frequency spectrum in a range of approximately 0.03 Hz to 0.25 Hz.

13 . The method of claim 8 , wherein the converting the filtered error signal to the pitch offset signal includes calculating a difference between an actual pitch angle value of at least one rotor blade and a desired blade pitch angle of at least one rotor blade, wherein the difference defines the pitch offset signal.

14 . The method of claim 8 , wherein the pitch offset signal is calculated from the filtered error signal according to a function with the following properties:
a term proportional to a current value of the filtered error signal; a term proportional to a time integral of the filtered error signal; and a term proportional to a time derivative of the filtered error signal

15 . A computer system, comprising:
a processor; a memory device coupled to the processor; a pitch controller coupled to the processor; and a computer readable storage device coupled to the processor, wherein the storage device contains program code executable by the processor via the memory device to implement a method for reducing loads induced by ocean waves on a floating wind turbine tower, the method comprising:
calculating, by a processor of a computing system, an error signal defined by a moment imbalance between a tower bottom moment and a thrust moment of the floating wind turbine;
filtering, by the processor, the error signal in a frequency range attributable to ocean wave activity to eliminate frequencies contributing to the error signal that are not attributable to ocean wave activity, resulting in a filtered error signal;
converting, by the processor, the filtered error signal to a pitch offset signal; and
adjusting, by the processor, a blade pitch angle of at least one rotor blade of the floating wind turbine according to the pitch offset signal.

16 . The computer system of claim 15 , wherein the tower bottom moment is a moment at a platform top of the floating wind turbine as a result of environmental loads, and the thrust moment is a moment defined by a thrust force of rotor blades of the floating wind turbine measured at a location of a tower section of the floating turbine proximate the platform top.

17 . The computer system of claim 15 , wherein the error signal is filtered using a bandpass filter tuned to filter out frequencies above or below the frequency range attributable to ocean wave activity, further wherein the frequency range attributable to ocean wave activity is defined by an ocean wave frequency spectrum in a range of approximately 0.03 Hz to 0.25 Hz.

18 . The computer system of claim 15 , wherein the converting the filtered error signal to the pitch offset signal includes calculating a difference between an actual pitch angle value of at least one rotor blade and a desired blade pitch angle of at least one rotor blade, wherein the difference defines the pitch offset signal.

19 . A computer program product, comprising a computer readable hardware storage device storing a computer readable program code, the computer readable program code comprising an algorithm that when executed by a computer processor of a computing system implements a method according to claim 8 .

Assignees

• Siemens Gamesa Renewable Energy As

Inventors

• Frank Jared
• Guntur Srinivas
• Masciola Marco

Classifications

• Y02E10/727

  Offshore wind turbines · CPC title

• F05B2270/342

  Wave conditions, e.g. amplitude, frequency or direction · CPC title

• F05B2270/331

  Mechanical loads · CPC title

• F05B2240/93

  on a structure floating on a liquid surface · CPC title

• F03D13/25

  specially adapted for offshore installation · CPC title