Controlling power extraction for wind power generation
View Patent ↗A power generation system is disclosed. The power generation system comprises a kite connected to a line. The line is alternatively let out during a traction phase and recovered during a recovery phase. A power extractor connected to the line to extract power during the traction phase. And, a power extraction controller configured to target a preferred traction phase line velocity and a preferred recovery phase line velocity.
1. A power generation system comprising:
a kite connected to a line wherein the line is alternatively let out during a traction phase and recovered during a recovery phase;
a power extractor connected to the line to extract power during the traction phase;
a power extraction controller configured to target a preferred traction phase line velocity and a preferred recovery phase line velocity.
2. A system as in claim 1 , wherein the power extractor comprises an electric generator.
3. A system as in claim 1 , wherein the power extraction controller is configured to determine a velocity ratio based at least in part on the preferred traction phase line velocity and the preferred recovery phase line velocity.
4. A system as in claim 3 , wherein the velocity ratio is based at least in part on a force ratio.
5. A system as in claim 4 , wherein the power extraction controller improves the force ratio to improve power extraction efficiency by changing the force ratio from a first ratio to a second ratio and measuring power extraction efficiency to determine whether the first ratio or the second ratio is more efficient for power extraction.
6. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred traction phase line velocity based at least in part on a wind speed.
7. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred recovery phase line velocity based at least in part on a wind speed.
8. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred traction phase line velocity based at least in part on a line load.
9. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred recovery phase line velocity based at least in part on a line load.
10. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred traction phase line velocity based at least in part on one or more of the following: a line length, a kite angle to a line, a kite position, an image captured by a camera, a radar, a pressure sensor, a location sensor, or a global positioning sensor.
11. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred recovery phase line velocity based at least in part on one or more of the following: a line length, a kite angle to a line, a kite position, an image captured by a camera, a radar, a pressure sensor, a location sensor, or a global positioning sensor.
12. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred traction phase line velocity based at least in part on a constraint due to the power extractor.
13. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred recovery phase line velocity based at least in part on a constraint due to the power extractor.
14. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred traction phase line velocity based at least in part on a constraint due to a force limit.
15. A system as in claim 1 , wherein the power extraction controller is configured to determine the preferred recovery phase line velocity based at least in part on a constraint due to a force limit.
16. A system as in claim 1 , wherein the power extraction controller is configured to determine a traction phase line velocity near a turn around based at least in part on a constraint due to a line length.
17. A system as in claim 1 , wherein the power extraction controller is configured to determine a recovery phase line velocity near a turn around based at least in part on a constraint due to a line length.
18. A system as in claim 1 , wherein the power extraction controller is configured to maintain a tension on the line by applying a retarding torque during the traction phase.
19. A method for power generation comprising:
determining a preferred traction phase line velocity and a preferred recovery phase line velocity;
configuring a controller to target the preferred traction phase line velocity for a line connected to a kite during a traction phase, wherein during the traction phase the line is let out and power is extracted as the line is being let out; and
configuring a controller to target the preferred recovery phase line velocity a line connected to the kite during a recovery phase, wherein during the recovery phase the line is recovered.
20. A method as in claim 19 , wherein power is extracted using an electric generator.
21. A method as in claim 19 , wherein a velocity ratio is determined based at least in part on the preferred traction phase line velocity and the preferred recovery phase line velocity.
22. A method as in claim 21 , wherein the velocity ratio is based at least in part on a force ratio.
23. A method as in claim 22 , wherein the controller improves power extraction efficiency by changing the force ratio from a first ratio to a second ratio and measuring power extraction efficiency to determine whether the first ratio or the second ratio is more efficient for power extraction.
24. A method as in claim 19 , wherein the preferred traction phase line velocity is based at least in part on a wind speed.
25. A method as in claim 19 , wherein the preferred recovery phase line velocity is based at least in part on a wind speed.
26. A method as in claim 19 , wherein the preferred traction phase line velocity is based at least in part on a line load.
27. A method as in claim 19 , wherein the preferred recovery phase line velocity is based at least in part on a line load.
28. A method as in claim 19 , wherein the preferred traction phase line velocity is based at least in part on one or more of the following: a line length, a kite angle to a line, a kite position, an image captured by a camera, a radar, a pressure sensor, a location sensor, or a global positioning sensor.
29. A method as in claim 19 , wherein the preferred recovery phase line velocity is based at least in part on one or more of the following: a line length, a kite angle to a line, a kite position, an image captured by a camera, a radar, a pressure sensor, a location sensor, or a global positioning sensor.
30. A method as in claim 19 , wherein the preferred traction phase line velocity is based at least in part on a power extractor constraint.
31. A method as in claim 19 , wherein the preferred recovery phase line velocity is based at least in part on a power extractor constraint.
32. A method as in claim 19 , wherein the preferred traction phase line velocity is based at least in part on a force limit constraint.
33. A method as in claim 19 , wherein the preferred recovery phase line velocity is based at least in part on a force limit constraint.
34. A method as in claim 19 , further comprising determining a traction phase line velocity near a turn around that is based at least in part on a line length.
35. A method as in claim 19 , further comprising determining a recovery phase line velocity near a turn around that is based at least in part on a line length.
36. A computer program product for power generation, the computer program product being embodied in a computer readable medium and comprising computer instructions for:
determining a preferred traction phase line velocity and a preferred recovery phase line velocity;
configuring a controller to target the preferred traction phase line velocity for a line connected to a kite during a traction phase, wherein during the traction phase the line is let out and power is extracted as the line is being let out; and
configuring a controller to target the preferred recovery phase line velocity a line connected to the kite during a recovery phase, wherein during the recovery phase the line is recovered.