EP-4735762-A1 - ACTIVATION OF WIND TURBINE PITCH CONTROL BASED ON RATE OF CHANGE OF WIND TURBINE COMPONENT OSCILLATION

EP4735762A1EP 4735762 A1EP4735762 A1EP 4735762A1EP-4735762-A1

Abstract

The invention relates to activation of a pitch controller for controlling pitch of rotor blades of a wind turbine. The invention includes receiving a sensor signal, from at least one sensor of the wind turbine, indicative of oscillatory motion of a component of the wind turbine. The invention includes determining, based on the received sensor signal, a magnitude of the oscillatory motion of the component, and determining, based on the determined magnitude, a rate of change of the magnitude of oscillatory motion. The invention includes controlling activation of the pitch controller based on the determined rate of change of the magnitude of oscillatory motion.

Inventors

GILES, Alexander Duncan
MARTINS CUNHA, Bruno

Assignees

VESTAS WIND SYSTEMS A/S

Dates

Publication Date: 20260506
Application Date: 20240626

Claims (15)

1. An activation controller for a wind turbine having a plurality of rotor blades, the activation controller being for controlling activation of a pitch controller that is for controlling pitch of the rotor blades, the activation controller being configured to: receive a sensor signal, from at least one sensor of the wind turbine, indicative of oscillatory motion of a component of the wind turbine; determine, based on the received sensor signal, a magnitude of the oscillatory motion of the component; determine, based on the determined magnitude, a rate of change of the magnitude of oscillatory motion; and, control activation of the pitch controller based on the determined rate of change of the magnitude of oscillatory motion.
2. An activation controller according to Claim 1 , wherein the activation controller is configured to activate the pitch controller if the determined rate of change is greater than zero; optionally, wherein the activation controller is configured to deactivate the pitch controller if the determined rate of change is less than zero.
3. An activation controller according to Claim 2, wherein the activation controller is configured to activate the pitch controller if the determined rate of change is greater than a threshold rate of change value that is greater than zero.
4. An activation controller according to any previous claim, the activation controller being configured to control activation of the pitch controller based on the determined magnitude of oscillatory motion of the component.
5. An activation controller according to Claim 4, wherein the activation controller is configured to activate the pitch controller if the determined magnitude of oscillatory motion of the component is greater than a threshold magnitude value greater than zero; optionally, wherein the activation controller is configured to deactivate the pitch controller if the determined magnitude of oscillatory motion of the component is less than a second threshold magnitude value; further optionally, wherein the second threshold magnitude value is less than or equal to the threshold magnitude value.
6. An activation controller according to Claim 5, wherein the threshold magnitude value is dependent on whether the wind turbine is operating in a full-load region or a partial-load region of a power curve of the wind turbine; optionally, wherein the threshold magnitude value is greater when the wind turbine is operating in the partial-load region than in the full-load region.
7. An activation controller according to Claim 1 , wherein the activation controller is configured to activate the pitch controller if a predicted magnitude is greater than a defined predicted magnitude threshold value, wherein the predicted magnitude is a sum of the determined magnitude and the determined rate of change of the magnitude multiplied by a constant value.
8. A controller according to any previous claim, the controller being configured to isolate frequency content in the received sensor signal around a defined target frequency, wherein the determined magnitude is a magnitude of oscillatory motion around the defined target frequency, the magnitude being determined based on the isolated frequency content; optionally, wherein the defined target frequency is nP, where n is a positive integer.
9. A controller according to Claim 8, wherein to isolate the frequency content the controller is configured to: generate, based on the received sensor signal, a pair of mutually orthogonal components based on the defined target frequency; and, apply one or more filters to each of the pair of mutually orthogonal components to isolate the frequency content around the defined target frequency, wherein the magnitude of oscillatory motion is determined based on the filtered pair of mutually orthogonal components.
10. A controller according to Claim 9, wherein the pair of mutually orthogonal components are generated according to: where D and Q are the pair of mutually orthogonal components, t is time, A is the received sensor signal, and H rot is the defined target frequency; optionally wherein the controller is configured to apply a filter to the determined magnitude prior to determining the rate of change of the magnitude, wherein the filter is: a low pass filter; or, a notch filter at 2Q. rot .
11. A controller according to any previous claim, wherein the received sensor signal from the at least one sensor signal is an acceleration signal from an acceleration sensor at a top of a tower of the wind turbine or in a nacelle of the wind turbine, wherein the magnitude of the oscillatory motion of the component is the magnitude of fore-aft oscillation of the tower or nacelle, and wherein the pitch controller is a collective pitch controller for adjusting collective pitch of the plurality of rotor blades.
12. A controller according to Claim 11 when dependent on Claim 8, wherein the wind turbine comprises three rotor blades, and wherein the defined target frequency is 3P; optionally, wherein the wind turbine is an offshore wind turbine in which the tower is coupled to a floating platform.
13. A controller according to any of Claims 8 to 10, wherein the received sensor signal from the at least one sensor signal is an acceleration signal from an acceleration sensor at a top of a tower of the wind turbine or in a nacelle of the wind turbine, wherein the magnitude of the oscillatory motion of the component is the magnitude of side-to-side oscillation of the tower or nacelle, wherein the wind turbine comprises three rotor blades, wherein the defined target frequency is 6P, and wherein the pitch controller is a collective pitch controller for adjusting collective pitch of the plurality of rotor blades.
14. A wind turbine comprising an activation controller according to any previous claim.
15. A method for a wind turbine having a plurality of rotor blades, the method being for controlling activation of a pitch controller that is for controlling pitch of the rotor blades, the method comprising: receiving a sensor signal, from at least one sensor of the wind turbine, indicative of oscillatory motion of a component of the wind turbine; determining, based on the received sensor signal, a magnitude of the oscillatory motion of the component; determining, based on the determined magnitude, a rate of change of the magnitude of oscillatory motion; and, controlling activation of the pitch controller based on the determined rate of change of the magnitude of oscillatory motion.

Description

ACTIVATION OF WIND TURBINE PITCH CONTROL BASED ON RATE OF CHANGE OF WIND TURBINE COMPONENT OSCILLATION TECHNICAL FIELD The invention relates to activation of a pitch controller of a wind turbine and, in particular, to activation of the pitch controller based on a rate of change of oscillation of a component, e.g. tower, of the wind turbine. BACKGROUND Wind turbines as known in the art include a wind turbine tower supporting a nacelle and a rotor with a number of - typically, three - pitch-adjustable rotor blades mounted thereto. A wind turbine is prone to vibrations, such as tower, nacelle, or rotor blade movement. It is known that certain types of vibrations may be damped by active pitching of the rotor blades or adjusting generator torque. Control strategies for adjusting blade pitch can be used to maximise energy production of a wind turbine while minimising loads experienced by various components of the wind turbine. Rotor blades may be adjusted as part of a collective pitch control routine, in which each of the (three) blades are adjusted in the same way at the same time. Collective pitch control may be used to control wind turbine speed, for instance. Rotor blades may also be adjusted as part of an individual pitch control routine, in which each blade has its own individual pitch reference, possibly as an adjustment to a collective pitch reference from a collective pitch controller. Collective and individual pitch control may be used to alleviate loads on components of the wind turbine, e.g. caused by rotational sampling of the wind field in the vicinity of wind turbine as the rotor rotates. Continuous or excessive activation of a high-frequency collective or individual pitch controller may cause excessive wear of the pitch bearings. As such, collective and individual pitch control schemes may be combined with activation strategies that allow for certain key loading issues associated with wind turbine operation to be handled or addressed without putting excessive demands on the blade bearing. There is a need to further improve collective and individual blade control to balance the alleviation of loads against ensuring excessive demands are not placed on the blade bearing. It is against this background to which the present invention is set. SUMMARY OF THE INVENTION According to an aspect of the present invention there is provided an activation controller for a wind turbine having a plurality of rotor blades. The activation controller is for controlling activation of a pitch controller that is for controlling pitch of the rotor blades. The activation controller is configured to receive a sensor signal, from at least one sensor of the wind turbine, indicative of oscillatory motion of a component of the wind turbine. The activation controller is configured to determine, based on the received sensor signal, a magnitude of the oscillatory motion of the component. The activation controller is configured to determine, based on the determined magnitude, a rate of change of the magnitude of oscillatory motion. The activation controller is configured to control activation of the pitch controller based on the determined rate of change of the magnitude of oscillatory motion. The activation controller may be configured to activate the pitch controller if the determined rate of change is greater than zero. Optionally, the activation controller may be configured to deactivate the pitch controller if the determined rate of change is less than zero. The activation controller may be configured to activate the pitch controller if the determined rate of change is greater than a threshold rate of change value that is greater than zero. The activation controller may be configured to control activation of the pitch controller based on the determined magnitude of oscillatory motion of the component. The activation controller may be configured to activate the pitch controller if the determined magnitude of oscillatory motion of the component is greater than a threshold magnitude value greater than zero. Optionally, the activation controller may be configured to deactivate the pitch controller if the determined magnitude of oscillatory motion of the component is less than a second threshold magnitude value. Further optionally, the second threshold magnitude value may be less than or equal to the threshold magnitude value. The activation controller may be configured to activate the pitch controller if a predicted magnitude is greater than a defined predicted magnitude threshold value. The predicted magnitude may be a sum of the determined magnitude and the determined rate of change of the magnitude multiplied by a constant value. The threshold magnitude value may be dependent on whether the wind turbine is operating in a full-load region or a partial-load region of a power curve of the wind turbine. Optionally, the threshold magnitude value may be greater when the wind turbine is operating in the partial-load region than in