Cyclic Pitch Control System for Wind Turbine Blades
First Claim
1. A method of increasing the clearance between a blade tip and a base of a tower for tower-crossing rotor blades of a wind turbine having a tower and a plurality of wind-driven rotatable blades supported thereon, comprising:
- a) providing a control system adapted to feather individual blades of said plurality of blades;
b) providing an azimuthal encoder for electronic communication with said control system;
c) having the azimuthal encoder provide input to said control system to sense the approach of any one of said plurality of blades to said base in real-time; and
,d) having the control system respond to said encoder input by feathering each said approaching tower-crossing blade as a function of a sensed azimuthal position of said blade.
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Accused Products
Abstract
In a wind turbine, an open loop control algorithm for incrementally or positively adjusting the pitch angles of individual rotor blades may be used to increase spacing between the base of the turbine tower and an approaching blade tip. As each rotating blade passes in front of the tower base, a minimum clearance distance may be assured to avoid blade tip strikes of the base. In accordance with at least one embodiment of the control algorithm, as each blade approaches the tower base, it may be feathered to reduce its power loading, and to facilitate increased clearance beyond the normal unloading or feathering produced by the so-called tower shadow effect. To offset resultant loss of torque, the remaining blades may be correspondingly pitched toward power, i.e. into the wind, to balance and/or smooth out the overall rotor torque curve, and thus to avoid torque ripples.
38 Citations
19 Claims
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1. A method of increasing the clearance between a blade tip and a base of a tower for tower-crossing rotor blades of a wind turbine having a tower and a plurality of wind-driven rotatable blades supported thereon, comprising:
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a) providing a control system adapted to feather individual blades of said plurality of blades; b) providing an azimuthal encoder for electronic communication with said control system; c) having the azimuthal encoder provide input to said control system to sense the approach of any one of said plurality of blades to said base in real-time; and
,d) having the control system respond to said encoder input by feathering each said approaching tower-crossing blade as a function of a sensed azimuthal position of said blade. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of increasing the clearance between a blade tip and a base of a tower for tower-crossing rotor blades of a wind turbine having a tower and a plurality of wind-driven rotatable blades supported thereon, comprising:
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a) providing a control system adapted to feather individual blades of said plurality of blades; b) providing an azimuthal encoder for electronic communication with said control system; c) having the azimuthal encoder provide input to said control system to sense the azimuthal position of the blades; d) having the control system respond to said encoder input by feathering each said approaching tower-crossing blade as a function of a sensed azimuthal position of said blade; and
,e) having the control system respond to said encoder input by over-pitching the remaining, non-tower crossing, blades as each tower-crossing blade is feathered, to compensate for loss of torque attributable to the feathering of the tower crossing blade. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification