A partial pitch wind turbine is described wherein the wind turbine blade has an inner blade section designed for stall-controlled operation and an outer blade section designed for pitch-controlled operation. The different blade profiles for the different sections allow for the efficient operation of
A partial pitch wind turbine is described wherein the wind turbine blade has an inner blade section designed for stall-controlled operation and an outer blade section designed for pitch-controlled operation. The different blade profiles for the different sections allow for the efficient operation of the blade while providing for the control of the wind turbine to effectively reduce blade root moments. The outer blade sections can be pitched out of the wind to reduce root moments due to the outer blade sections, while the increasing power capture of the inner blade section maintains nominal power output.
대표청구항▼
1. A partial pitch wind turbine blade of at least 35 meters length, the blade comprising: an inner blade section;an outer blade section coupled to said inner blade section at a pitch junction, said outer blade section operable to pitch relative to said inner blade section, whereinsaid inner blade se
1. A partial pitch wind turbine blade of at least 35 meters length, the blade comprising: an inner blade section;an outer blade section coupled to said inner blade section at a pitch junction, said outer blade section operable to pitch relative to said inner blade section, whereinsaid inner blade section comprises a first blade profile for a stall-controlled aerodynamic blade with a first aerodynamic profile having a first maximum lift coefficient (CLmax1) and a first cord (Ch1) at the end facing said pitch junction and whereinsaid outer blade section comprises a second blade profile for a pitch-controlled aerodynamic blade with a second aerodynamic profile having a second maximum lift coefficient (CLmax2) and a second cord (Ch2) at the end facing said pitch junction, andwherein said blade comprises a discontinuity between said first and second blade profiles between said pitch junction, which discontinuity is such that [(CLmax1)×(Ch1)] is at least 20% greater than [(CLmax2)×(Ch2)]. 2. A partial pitch blade as claimed in claim 1, wherein said inner blade section is designed to enter stall for a greater angle of attack than said outer blade section. 3. A partial pitch blade as claimed in claim 1, wherein the inner blade section has greater cord length than the outer blade section. 4. A partial pitch blade as claimed in claim 1, wherein the profile of said outer blade section has a greater camber than the profile of said inner blade section at the blade section ends facing each other. 5. A partial pitch blade as claimed in claim 1, wherein at least one high-lift device is provided on said inner blade section to suppress stall of said inner blade section. 6. A partial pitch blade as claimed in claim 5, wherein said at least one high-lift device is selected from one or more of the following: a vortex generator, a gurney flap, a spoiler, a leading-edge slat/slot, boundary-layer control devices. 7. A partial pitch blade as claimed in claim 1, wherein the wind turbine blade comprises at least one stall fence provided at said pitch junction. 8. A partial pitch blade as claimed in claim 1, wherein the surface area of said inner blade section is substantially equivalent to the surface area of said outer blade section. 9. A partial pitch blade as claimed in claim 1, wherein the longitudinal length of said inner blade section is approximately equal to half the longitudinal length of said outer blade section. 10. A partial pitch blade as claimed in claim 1, wherein taken from the root of the blade along the longitudinal length of the blade, the distal ⅔ of said inner blade section has an average chord length of C1 and the distal ⅔ of said outer blade section has an average chord length of C2, and wherein the length of C1 is greater than or equal to twice the length of C2. 11. A partial pitch blade as claimed in claim 1, wherein the blade comprises at least one transition zone provided between said first and second blade profiles at said pitch junction. 12. A partial pitch blade as claimed in claim 11, wherein said outer blade section comprises an outer tip end and an inner pitch end, and wherein the blade further comprises an outer blade transition zone provided between the inner pitch end of said outer blade section and said pitch junction, wherein the blade comprises a discontinuity between the first blade profile at said pitch junction and the second blade profile at the inner pitch end of said outer blade section. 13. A partial pitch blade as claimed in claim 11, wherein said inner blade section comprises an outer pitch end and an inner root end, and wherein the blade further comprises an inner blade transition zone provided between the outer pitch end of said inner blade section and said pitch junction, wherein the blade comprises a discontinuity between the first blade profile at the outer pitch end of said inner blade section and the second blade profile at the pitch junction. 14. A partial pitch wind turbine comprising: a wind turbine tower;a nacelle provided at the top of said tower; andat least two partial pitch rotor blades as claimed in claim 1, said rotor blades provided on a rotor hub located at said nacelle,wherein when the outer blade sections are unpitched relative to the inner blade sections of said partial pitch rotor blades said wind turbine is operable to generate nominal output power at a first wind speed, and wherein the inner blade sections are designed to enter stall at a second wind speed greater than said first wind speed. 15. A partial pitch wind turbine as claimed in claim 14, wherein the wind turbine further comprises a controller, the controller operable to pitch said outer blade sections out of the wind for wind speeds above said first wind speed, as the power capture of said inner blade sections increases between said first wind speed and said second wind speed and said controller is operable to pitch said outer blade sections out of the wind to maintain nominal output power for wind speed above said first wind speed.
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이 특허에 인용된 특허 (8)
Shimmel David M. (Tracy CA), Hydraulic control device for wind turbine.
Fradenburgh Evan A. (Fairfield CT) Davis S. Jon (Orange CT) Moffitt Robert C. (Seymour CT) Visintainer Joseph A. (Beacon Falls CT), Variable diameter rotor having an offset twist.
Rob, Fons; Madsen, Jesper; Ejlersen, Flemming; Quiring, Peter, Wind turbine blade assembled from inboard part and outboard part having different types of load carrying structures.
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