Method for the individual pitch control of rotor blades of a wind turbine, and wind turbines
A method for the individual pitch control of the rotor blades of a wind turbine is provided herein. In some embodiments, the method includes measuring an acceleration by an acceleration sensor in a rotor blade of the wind turbine; high-pass filtering of a signal of the acceleration sensor in order to determine a time-variant variable; and setting the pitch of the first rotor blade of the wind turbine using the time-variant variable, the pitch setting being part of an individual pitch control.
1. A method for the individual pitch control of rotor blades of a wind turbine, comprising:
measuring acceleration by means of a fiber-optic acceleration sensor in a rotor blade of the wind turbine;
opto-electronically converting a signal of the fiber-optic acceleration sensor;
filtering the opto-electronically converted acceleration signal by means of an analog anti-aliasing filter;
high-pass filtering the signal of the fiber-optic acceleration sensor to determine a time-variable parameter, and
setting the pitch of the rotor blade of the wind turbine using the time-variable parameter, said pitch setting being performed in the course of an individual pitch control.
2. The method according to claim 1 , wherein the fiber-optic acceleration sensor is provided at a radial position in the range of the outer 70% of the radius of a first rotor blade.
3. The method according to claim 1 , wherein the high-pass filtering is performed by forming a time derivative, by high-pass filtering and/or by means of Fourier transformation.
4. The method according to claim 1 , wherein the high-pass filtering has a cutoff frequency from 0.3 to 0.5 Hz.
5. The method according to claim 1 , wherein the filtering of the opto-electronically converted acceleration signal by means of the analog anti-aliasing filter has a cutoff frequency from 10 Hz to 40 Hz.
6. The method according to claim 1 , wherein the signal of the fiber-optic acceleration sensor is guided to the hub by means of a light conductor.
7. The method according to claim 6 , wherein the light conductor is provided at the rear edge of the rotor blade.
8. The method according to claim 6 , wherein the light conductor is provided on a profile provided at the rear edge of the rotor blade.
9. The method according to claim 8 , wherein the profile is a pultruded profile and/or wherein the profile causes the rotor blade to be aerodynamically influenced.
10. The method according to claim 8 , wherein the profile extends along at least 10% or at least 30% of the rotor blade radius.
11. The method according to claim 8 , wherein the acceleration sensor is provided within the profile.
12. The method according to claim 7 , wherein the light conductor is guided into the rotor blade interior from outside at a radial position where the rotor blade can be walked in.
13. A wind turbine, comprising:
a first rotor blade mounted to a hub;
a first drive unit for rotating the first rotor blade for a pitch control of the first rotor blade;
at least one second rotor blade mounted to the hub;
at least one second drive unit for rotating the second rotor blade for a pitch control of the second rotor blade, wherein the second drive unit is controllable independent of the first drive unit;
a control unit for controlling at least the first drive unit;
a fiber-optic acceleration sensor in the wind turbine's first rotor blade;
an opto-electronic converter for converting a signal of the fiber-optic acceleration sensor; and
an analog anti-aliasing filter configured to filter the opto-electronically converted acceleration signal,
wherein the control unit is configured to control pitching of the first rotor blade using a time-variable parameter, and
wherein the time-variable parameter is determined by high-pass filtering the signal of the fiber-optic acceleration-sensor.
14. The wind turbine according to claim 13 , wherein the fiber-optic acceleration sensor is provided at a radial position in the range of the outer 70% of the radius of the first rotor blade.
15. The wind turbine according to claim 13 , wherein the acceleration sensor is made of less than 10% by weight from metal or contains less than 20 g of metal.
16. The wind turbine according to claim 13 , furthermore comprising:
a light conductor which is guided from the fiber-optic acceleration sensor to a radial rotor blade position where the rotor blade can be walked in.
17. The wind turbine according to claim 16 , wherein the fiber-optic acceleration sensor has a maximum expansion of 10 mm in a cross-section perpendicular to an axis of the light conductor.
18. The wind turbine according to claim 16 , wherein the light conductor is provided at the rear edge of the rotor blade.
19. The wind turbine according to claim 16 , wherein the light conductor is provided on a profile provided at the rear edge of the rotor blade.
20. The wind turbine according to claim 19 , wherein the profile is at least one of a pultruded profile and configured to cause the rotor blade to be aerodynamically influenced.
21. The wind turbine according to claim 19 , wherein the fiber-optic acceleration sensor is provided within the profile.