Patent US5155375A successfully refreshed from Google Patents.
US5155375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed control system for a variable speed wind turbine
Assignee: Fleet Capital Corp
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Filing: 1991-09-19
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Granted: 1992-10-13
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Expires: 2011-09-19
Abstract
Abstract A controller and method is disclosed for operating a variable speed turbine to better track wind speed fluctuations for greater efficiency in conversion of wind energy to electrical energy. The controller of the invention controls the rotor speed in accordance with a wind speed supplied by a wind observer in order to approximately follow the varying wind speeds. The wind observer predicts the average wind speed at a subsequent point in time over the cross-section presented to the wind by the wind turbine. The average wind speed is applied to a parameter schedule to determine desired values for rotor speed and torque which are used by arotor speed stabilizer to command a reference load torque. The load torque of the generator is controlled in accordance with the commanded load torque, and therefore the desired rotor speed is approximated. During operation, the wind speed prediction process is repeated at each subsequent time interval, and the load torque, and therefore rotor speed, is controlled accordingly. The wind observer calculates the aerodynamic torque and then calculates net torque. The wind speed is predicted as a function of the present (previously predicted) wind speed and correction terms including net torque and the difference between the predicted and actual rotor speed. The wind observer is useful whenever the wind turbine rotor is turning, whether or not it is producing power.
Inventors
- 👤 William E. Holley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:24
CPC Classifications
F; F03; F03D; F03D7/00; F03D7/02; F03D7/028; F03D7/022; F03D7/0224; F03D7/0276; F03D7/04; F03D7/042; F03D7/043; H; H02; H02P; H02P9/00; H02P9/04; F05; F05B; F05B2260/00; F05B2260/82; F05B2260/821; F05B2270/00; F05B2270/10; F05B2270/101; F05B2270/103; F05B2270/1032; F05B2270/20; F05B2270/30; F05B2270/32; F05B2270/329; F05B2270/335; H02P2101/00; H02P2101/15; Y; Y02; Y02A; Y02A30/00; Y02E; Y02E10/00; Y02E10/70; Y02E10/72
Claims Analysis
Total Claims: 78
Claim 1
Independent Claim
111 words
A controller for a variable speed electrical generator having a rotor driven with a driving torque supplied by a power source that varies over time, said controller comprising: means for predicting a power parameter indicative of the amount of power that will be available from the varying power source at a subsequent point in time; means responsive to said predicted power parameter for selecting a desired rotor speed at said subsequent point in time; and means for selecting a control parameter to be applied to control a rotor speed at said subsequent point in time, said control parameter being selected so that the rotor speed will approximate said desired rotor speed.
Claim 2
Dependent Claim
111 words
A controller for a variable speed electrical generator having a rotor driven with a driving torque supplied by a power source that varies over time, said controller comprising: means for predicting a power parameter indicative of the amount of power that will be available from the varying power source at a subsequent point in time; means responsive to said predicted power parameter for selecting a desired rotor speed at said subsequent point in time; and means for selecting a control parameter to be applied to control a rotor speed at said subsequent point in time, said control parameter being selected so that the rotor speed will approximate said desired rotor speed.
Claim 3
Dependent Claim
20 words
The variable speed generator controller of claim 1, further comprising means for controlling the rotor speed with the control parameter.
Claim 4
Dependent Claim
37 words
The variable speed generator controller of claim 1 wherein said means for selecting a control parameter further comprises means for calculating a reference load torque to be applied to the generator at said subsequent point in time.
Claim 5
Dependent Claim
20 words
The variable speed generator controller of claim 3 further comprising means for applying said reference load torque to the generator.
Claim 6
Dependent Claim
31 words
The variable speed generator controller of claim 1 wherein said means for predicting said power parameter further comprises means for estimating an amount of driving torque being applied to the rotor.
Claim 7
Dependent Claim
43 words
The variable speed generator controller of claim 5 further comprising: a rotor speed sensor for supplying a sensed rotor speed parameter; and means for calculating a rotor speed error and applying said rotor speed error to said means for selecting the power parameter.
Claim 8
Dependent Claim
78 words
The variable speed generator controller of claim 1 wherein the means for predicting a power parameter further comprises: means for estimating a net torque being applied to the rotor, including means for estimating an amount of driving torque being applied to the rotor, means for estimating an amount of load torque being applied to the rotor, and means for calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 9
Dependent Claim
52 words
The variable speed generator controller of claim 1 further comprising means for applying said means for predicting a power parameter, said means for selecting a desired rotor speed, and said means for selecting a control parameter selection, to provide a control parameter at each of a series of subsequent points in time.
Claim 10
Dependent Claim
89 words
A controller for a variable speed electrical generator in a wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind which may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said controller comprising: means for estimating a wind speed over the swept area; means responsive to the estimated wind speed for selecting a desired rotor speed; and means for controlling the rotor speed to approximate said desired rotor speed.
Claim 11
Dependent Claim
89 words
A controller for a variable speed electrical generator in a wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind which may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said controller comprising: means for estimating a wind speed over the swept area; means responsive to the estimated wind speed for selecting a desired rotor speed; and means for controlling the rotor speed to approximate said desired rotor speed.
Claim 12
Dependent Claim
37 words
The variable speed generator controller of claim 9 wherein said means for controlling the rotor speed further comprises means for calculating a reference load torque to be applied to the generator at said subsequent point in time.
Claim 13
Dependent Claim
28 words
The variable speed generator controller of claim 10, wherein the means for controlling the rotor speed further comprises means for applying said reference load torque to the generator.
Claim 14
Dependent Claim
31 words
The variable speed generator controller of claim 9 wherein said means for predicting said wind speed further comprises means for estimating an amount of driving torque being applied to the rotor.
Claim 15
Dependent Claim
44 words
The variable speed generator controller of claim 12 further comprising: a rotor speed sensor for supplying a sensed rotor speed parameter; means for calculating a rotor speed error; and means for applying said rotor speed error to said means for controlling the rotor speed.
Claim 16
Dependent Claim
78 words
The variable speed generator controller of claim 9 wherein the means for estimating a wind speed further comprises: means for estimating a net torque being applied to the rotor, including means for estimating an amount of driving torque being applied to the rotor, means for estimating an amount of load torque being applied to the rotor, and means for calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 17
Dependent Claim
40 words
The variable speed generator controller of claim 9 wherein the aerodynamic surfaces have a pitch that is selectable by a pitch control mechanism, and wherein said means for controlling the rotor speed includes means for controlling said pitch control mechanism.
Claim 18
Dependent Claim
38 words
The variable speed generator controller of claim 15 further comprising: means for calculating a reference pitch angle dependent upon said wind speed; and means for controlling the pitch control mechanism in order to apply said reference pitch angle.
Claim 19
Dependent Claim
125 words
A controller for a variable speed electrical generator in a wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind that may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said controller comprising: means for predicting a wind speed over said swept area at a subsequent point in time; means responsive to the predicted wind speed for selecting a desired rotor speed at said subsequent point in time; and means for selecting a control parameter to be applied to control a rotor speed at said subsequent point in time, said control parameter being selected so that the rotor speed will approximate said desired rotor speed.
Claim 20
Dependent Claim
125 words
A controller for a variable speed electrical generator in a wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind that may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said controller comprising: means for predicting a wind speed over said swept area at a subsequent point in time; means responsive to the predicted wind speed for selecting a desired rotor speed at said subsequent point in time; and means for selecting a control parameter to be applied to control a rotor speed at said subsequent point in time, said control parameter being selected so that the rotor speed will approximate said desired rotor speed.
Claim 21
Dependent Claim
38 words
The variable speed generator controller of claim 17 wherein said means for selecting a control parameter further comprises a means for calculating a reference load torque to be applied to the generator at said subsequent point in time.
Claim 22
Dependent Claim
21 words
The variable speed generator controller of claim 18 further comprising a means for applying said reference load torque to the generator.
Claim 23
Dependent Claim
31 words
The variable speed generator controller of claim 17 wherein said means for predicting said wind speed further comprises means for estimating an amount of driving torque being applied to the rotor.
Claim 24
Dependent Claim
44 words
The variable speed generator controller of claim 20 further comprising: a rotor speed sensor for supplying a sensed rotor speed parameter; means for calculating a rotor speed error; and means for applying said rotor speed error to said means for selecting a control parameter.
Claim 25
Dependent Claim
78 words
The variable speed generator controller of claim 17 wherein the means for predicting a wind speed further comprises: means for estimating a net torque being applied to the rotor, including means for estimating an amount of driving torque being applied to the rotor, means for estimating an amount of load torque being applied to the rotor, and means for calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 26
Dependent Claim
133 words
A controller for selecting the load torque on a rotor in a variable speed wind turbine electrical generator, the wind supplying a driving torque to the rotor in a direction opposing the load torque, the amount of the driving torque varying over time with the wind speed, said controller comprising: means for predicting the average wind speed at a subsequent point in time; means for selecting a desired rotor speed dependent upon the predicted wind speed at said subsequent point in time; torque selecting means, responsive to said predicted wind speed and dependent upon said desired rotor speed, for selecting a reference load torque to be applied at said subsequent point in time, said reference load torque being selected so that the rotational speed of said rotor will approximate said desired rotor speed.
Claim 27
Dependent Claim
133 words
A controller for selecting the load torque on a rotor in a variable speed wind turbine electrical generator, the wind supplying a driving torque to the rotor in a direction opposing the load torque, the amount of the driving torque varying over time with the wind speed, said controller comprising: means for predicting the average wind speed at a subsequent point in time; means for selecting a desired rotor speed dependent upon the predicted wind speed at said subsequent point in time; torque selecting means, responsive to said predicted wind speed and dependent upon said desired rotor speed, for selecting a reference load torque to be applied at said subsequent point in time, said reference load torque being selected so that the rotational speed of said rotor will approximate said desired rotor speed.
Claim 28
Dependent Claim
30 words
The controller of claim 23 wherein the means for selecting a desired rotor speed includes a parameter schedule for applying the predicted wind speed to obtain a desired rotor speed.
Claim 29
Dependent Claim
26 words
The controller of claim 23 wherein the torque selecting means comprises a parameter schedule for applying the predicted wind speed to obtain a desired load torque.
Claim 30
Dependent Claim
44 words
The controller of claim 25 wherein the torque selecting means further includes: means for determining a stability correction term; and means for adding the desired load torque and the stability correction term to obtain the reference load torque to be applied to the generator.
Claim 31
Dependent Claim
52 words
The controller of claim 25 wherein the means for determining a stability correction term comprises a means for predicting a rotor speed at said subsequent point in time and also comprises a means for determining a rotor speed error as a function of the predicted rotor speed and the desired rotor speed.
Claim 32
Dependent Claim
44 words
The controller of claim 23 wherein the prediction means includes: means for determining a first correction term; means for estimating a current wind speed; and means for adding the current wind speed estimate to the first correction term to obtain a wind speed prediction.
Claim 33
Dependent Claim
43 words
The controller of claim 28 wherein the prediction means includes means for determining a second correction term and further includes means for adding the current wind speed estimate, the first correction term, and the second correction term to obtain a wind speed prediction.
Claim 34
Dependent Claim
47 words
The controller of claim 28 wherein the prediction means includes means for determining a driving torque applied to the rotor by the wind power, and the means for determining a first correction term includes means determining a first correction term as a function of the driving torque.
Claim 35
Dependent Claim
27 words
The controller of claim 23 wherein the prediction means includes a means for estimating the driving torque supplied by the wind power at the current time step.
Claim 36
Dependent Claim
26 words
The controller of claim 31 wherein the prediction means further includes a means for estimating the net torque on the rotor at the current time step.
Claim 37
Dependent Claim
28 words
The controller of claim 32 wherein the means for estimating the net torque includes subtracting the applied load torque from the driving torque from the applied load torque.
Claim 38
Dependent Claim
49 words
The controller of claim 32 wherein the prediction means includes means for determining a first correction term and a means for estimating a current wind speed, and further includes a means for adding the current wind speed estimate to the first correction term to obtain a wind speed prediction.
Claim 39
Dependent Claim
86 words
A wind speed observer for a wind turbine having a rotor driven by a wind applying power to at least one blade, said wind applying a driving torque to the rotor, said wind speed observer predicting an average wind speed over a sweep of the blades, said wind speed observer comprising: means for obtaining a parameter indicative of a rotor speed; means for estimating the average wind speed at a current time; and means for predicting the average wind speed at a subsequent point in time.
Claim 40
Dependent Claim
86 words
A wind speed observer for a wind turbine having a rotor driven by a wind applying power to at least one blade, said wind applying a driving torque to the rotor, said wind speed observer predicting an average wind speed over a sweep of the blades, said wind speed observer comprising: means for obtaining a parameter indicative of a rotor speed; means for estimating the average wind speed at a current time; and means for predicting the average wind speed at a subsequent point in time.
Claim 41
Dependent Claim
33 words
The wind speed observer of claim 35 further comprising means for estimating the driving torque applied by the wind, said estimating means being responsive to said rotor speed and said estimated wind speed.
Claim 42
Dependent Claim
69 words
The wind speed observer of claim 35 further comprising: means for estimating a net torque being applied to the rotor, including means for estimating an amount of driving torque being applied to the rotor, means for estimating an amount of load torque being applied to the rotor, and means for calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 43
Dependent Claim
56 words
The wind speed observer of claim 35 further comprising means for applying said means for obtaining a parameter indicative of a rotor speed, said means for estimating the average wind speed, and said means for predicting the average wind speed, to predict the average wind speed at each of a series of subsequent points in time.
Claim 44
Dependent Claim
53 words
The wind speed observer of claim 35 further comprising: means for obtaining a parameter indicative of the pitch angle of the blades; and means for estimating the driving torque applied by the wind speed, said estimating means being responsive to said rotor speed parameter, said estimated wind speed, and said pitch angle parameter.
Claim 45
Dependent Claim
146 words
A wind turbine controller for a variable speed wind turbine including a variable speed generator driven by a rotor, said wind turbine having one or more aerodynamic surfaces for converting wind power into a driving torque on the rotor, said controller estimating the wind speed averaged over the sweep of the aerodynamic surfaces, said controller selecting a reference load torque in response to the estimations for the wind speed in order to achieve efficient generator operation, said controller comprising: means for sensing the rotor speed; a wind speed observer including means for estimating the wind speed; a parameter schedule including values that provide a desired load torque and a desired rotor speed for the wind turbine as a function of wind speed; and a rotor speed stabilizer including means for commanding a reference load torque based on the desired load torque and the desired rotor speed.
Claim 46
Dependent Claim
146 words
A wind turbine controller for a variable speed wind turbine including a variable speed generator driven by a rotor, said wind turbine having one or more aerodynamic surfaces for converting wind power into a driving torque on the rotor, said controller estimating the wind speed averaged over the sweep of the aerodynamic surfaces, said controller selecting a reference load torque in response to the estimations for the wind speed in order to achieve efficient generator operation, said controller comprising: means for sensing the rotor speed; a wind speed observer including means for estimating the wind speed; a parameter schedule including values that provide a desired load torque and a desired rotor speed for the wind turbine as a function of wind speed; and a rotor speed stabilizer including means for commanding a reference load torque based on the desired load torque and the desired rotor speed.
Claim 47
Dependent Claim
75 words
The wind turbine controller of claim 40 wherein the wind speed observer further comprises: means for estimating a net torque being applied to the rotor, including said means for estimating an amount of driving torque being applied to the rotor, means for estimating an amount of load torque being applied to the rotor, and means for calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 48
Dependent Claim
47 words
The variable speed generator controller of claim 40 further comprising means for applying said wind speed observer, said parameter schedule, and said rotor speed stabilizer, to provide a reference load torque at each of a series of subsequent points in time separated by the time interval Δt.
Claim 49
Dependent Claim
86 words
The wind turbine controller of claim 40 further comprising: at least one aerodynamic blade having an adjustable aerodynamic surface angle; a sensor for sensing the aerodynamic surface angle of the blade; a blade aerodynamic actuator for controlling the aerodynamic surface angle; a parameter schedule including values that provide a desired angle of the aerodynamic surface as a function of wind speed; and means for commanding a reference angle of the aerodynamic surface based on the desired angle of the aerodynamic surface and the desired rotor speed.
Claim 50
Dependent Claim
173 words
A wind turbine controller for a variable speed wind turbine including a variable speed generator driven by a rotor, said wind turbine having one or more aerodynamic surfaces for converting wind power into a driving torque on the rotor, said controller predicting the wind speed averaged over the sweep of the aerodynamic surfaces, said controller selecting a reference load torque in response to the predictions for the wind speed in order to achieve efficient generator operation, said controller comprising: means for sensing the rotor speed; a wind speed observer including means for estimating the driving torque on the rotor at a present time t i , and, means for predicting the wind speed at a subsequent point in time t i +Δt; a parameter schedule including values that provide a desired load torque and a desired rotor speed for the wind turbine as a function of wind speed; and a rotor speed stabilizer including program means for commanding a reference load torque based on the desired load torque and the desired rotor speed.
Claim 51
Dependent Claim
173 words
A wind turbine controller for a variable speed wind turbine including a variable speed generator driven by a rotor, said wind turbine having one or more aerodynamic surfaces for converting wind power into a driving torque on the rotor, said controller predicting the wind speed averaged over the sweep of the aerodynamic surfaces, said controller selecting a reference load torque in response to the predictions for the wind speed in order to achieve efficient generator operation, said controller comprising: means for sensing the rotor speed; a wind speed observer including means for estimating the driving torque on the rotor at a present time t i , and, means for predicting the wind speed at a subsequent point in time t i +Δt; a parameter schedule including values that provide a desired load torque and a desired rotor speed for the wind turbine as a function of wind speed; and a rotor speed stabilizer including program means for commanding a reference load torque based on the desired load torque and the desired rotor speed.
Claim 52
Dependent Claim
75 words
The wind turbine controller of claim 44 wherein the wind speed observer further comprises: means for estimating a net torque being applied to the rotor, including said means for estimating an amount of driving torque being applied to the rotor, means for estimating an amount of load torque being applied to the rotor, and means for calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 53
Dependent Claim
47 words
The variable speed generator controller of claim 44 further comprising means for applying said wind speed observer, said parameter schedule, and said rotor speed stabilizer, to provide a reference load torque at each of a series of subsequent points in time separated by the time interval Δt.
Claim 54
Dependent Claim
76 words
The wind turbine controller of claim 44 further comprising: at least one aerodynamic blade having an adjustable pitch angle; a sensor for sensing the pitch angle of the blade; a blade pitch actuator for controlling the pitch angle; a parameter schedule including values that provide a desired blade pitch angle as a function of wind speed; and means for commanding a reference pitch angle based on the desired blade pitch angle and the desired rotor speed.
Claim 55
Dependent Claim
104 words
A wind speed sensing method for operating a variable speed wind turbine, said variable speed wind turbine having at least one blade sweeping over a swept area, the blades turning a rotor in a generator, comprising the steps of: (a) allowing the wind turbine to rotate during operation in low wind when no power is being generated; (b) monitoring the rotor speed; (c) obtaining a wind speed estimate of the average wind speed present over the area swept by the blades, said wind speed estimate being based upon said rotor speed; and (d) obtaining a wind speed prediction for a subsequent point in time.
Claim 56
Dependent Claim
104 words
A wind speed sensing method for operating a variable speed wind turbine, said variable speed wind turbine having at least one blade sweeping over a swept area, the blades turning a rotor in a generator, comprising the steps of: (a) allowing the wind turbine to rotate during operation in low wind when no power is being generated; (b) monitoring the rotor speed; (c) obtaining a wind speed estimate of the average wind speed present over the area swept by the blades, said wind speed estimate being based upon said rotor speed; and (d) obtaining a wind speed prediction for a subsequent point in time.
Claim 57
Dependent Claim
34 words
The wind speed sensing method of claim 48 further comprising a step (e) repeating steps (a) through (d), to obtain a wind speed prediction at each of a series of subsequent points in time.
Claim 58
Dependent Claim
33 words
The wind speed sensing method of claim 48 further comprising a step (d) of monitoring the wind speed estimate over a time interval to obtain a average wind speed over said time interval.
Claim 59
Dependent Claim
35 words
The wind speed sensing method of claim 48 further comprising the steps of: (e) monitoring the average wind speed; and (f) generating power in the generator when a preselected average wind speed has been exceeded.
Claim 60
Independent Claim
126 words
A method for predicting the wind speed averaged over the sweep of the blades of a wind turbine, said method comprising the steps of: (a) estimating the present wind speed; (b) estimating an amount of driving torque applied to the rotor at the present time; (c) calculating a first correction term dependent upon said amount of driving torque estimated for said present time; (d) adding the estimated wind speed for the present time to said first correction term to predict the wind speed average for a subsequent point in time; and (e) at said subsequent point in time, repeating steps (a)-(d), and in the step (a) applying the wind speed predicted for said subsequent point in time as the wind speed estimate for the present time.
Claim 61
Independent Claim
126 words
A method for predicting the wind speed averaged over the sweep of the blades of a wind turbine, said method comprising the steps of: (a) estimating the present wind speed; (b) estimating an amount of driving torque applied to the rotor at the present time; (c) calculating a first correction term dependent upon said amount of driving torque estimated for said present time; (d) adding the estimated wind speed for the present time to said first correction term to predict the wind speed average for a subsequent point in time; and (e) at said subsequent point in time, repeating steps (a)-(d), and in the step (a) applying the wind speed predicted for said subsequent point in time as the wind speed estimate for the present time.
Claim 62
Dependent Claim
68 words
The method of claim 52 further comprising a step (f), estimating a net torque being applied to the rotor, including: estimating an amount of load torque being applied to the rotor, and calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque; wherein said step (c) further includes applying said estimated net torque to calculate the first correction term.
Claim 63
Dependent Claim
31 words
The method of claim 52 further comprising a step (f), repeating steps (a) through (e), to predict a wind speed average at each of a series of subsequent points in time.
Claim 64
Independent Claim
100 words
A method for controlling the rotor speed of a variable speed wind turbine, said method utilizing a parameter schedule of desired operating parameters indexed by the wind speed, said method comprising the steps of: (a) estimating the average wind speed at the present time; (b) predicting the average wind speed at a subsequent point in time; (c) selecting a desired rotor speed from the schedule of desired operating parameters; (d) supplying a control parameter for the wind turbine; and (e) adjusting the rotor speed in accordance with said control parameter, so that the rotor speed approximately follows the wind speed.
Claim 65
Independent Claim
100 words
A method for controlling the rotor speed of a variable speed wind turbine, said method utilizing a parameter schedule of desired operating parameters indexed by the wind speed, said method comprising the steps of: (a) estimating the average wind speed at the present time; (b) predicting the average wind speed at a subsequent point in time; (c) selecting a desired rotor speed from the schedule of desired operating parameters; (d) supplying a control parameter for the wind turbine; and (e) adjusting the rotor speed in accordance with said control parameter, so that the rotor speed approximately follows the wind speed.
Claim 66
Dependent Claim
52 words
The method of claim 55 wherein step (b) further comprises: estimating an amount of driving torque being applied to the rotor; estimating an amount of load torque being applied to the rotor; and calculating a difference between the estimated driving torque and the estimated load torque, to provide an estimated net torque.
Claim 67
Dependent Claim
31 words
The method of claim 55 further comprising a step (f) of repeating steps (a) through (e), to adjust the wind speed at each of a series of subsequent points in time.
Claim 68
Independent Claim
146 words
A method for supplying a control parameter to control a variable speed electrical generator in a wind turbine having rotor speed control dependent upon said control parameter, the wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind that may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said method comprising the steps of: (a) predicting a wind speed average over the swept area at a subsequent time step; (b) applying said wind speed predicted at said subsequent time step to select a desired rotor speed for said subsequent time step; and (c) applying said desired rotor speed to select a control parameter that can be applied to said rotor speed control so that said desired rotor speed will be approximated at said subsequent time step.
Claim 69
Independent Claim
146 words
A method for supplying a control parameter to control a variable speed electrical generator in a wind turbine having rotor speed control dependent upon said control parameter, the wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind that may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said method comprising the steps of: (a) predicting a wind speed average over the swept area at a subsequent time step; (b) applying said wind speed predicted at said subsequent time step to select a desired rotor speed for said subsequent time step; and (c) applying said desired rotor speed to select a control parameter that can be applied to said rotor speed control so that said desired rotor speed will be approximated at said subsequent time step.
Claim 70
Dependent Claim
88 words
The control method of claim 58 wherein said step (a), predicting a wind speed, further comprises the steps of: (d) estimating the wind speed at the present time; (e) estimating an amount of driving torque applied to the rotor at the present time; (f) calculating a first correction term dependent upon said amount of driving torque estimated for the present time; and (g) adding the estimated wind speed for the present time to said first correction term, to predict the wind speed average for the subsequent time step.
Claim 71
Dependent Claim
77 words
The control method of claim 59 wherein said step (a), predicting a wind speed, comprises the additional steps of: (h) sensing a sensed rotor speed at the present time; (i) calculating a rotor speed error at the present time; (j) calculating a second correction term based upon said rotor speed error; and (k) adding the second correction term to the wind speed predicted in the step (g) to predict the wind speed for said subsequent time step.
Claim 72
Dependent Claim
41 words
The control method of claim 58 wherein said step (c), applying said desired rotor speed to select a control parameter, further comprises the step of: calculating a reference load torque to be applied to the generator at said subsequent time step.
Claim 73
Independent Claim
231 words
A method for supplying a control parameter to control a variable speed electrical generator in a wind turbine having rotor speed control dependent upon said control parameter, the wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind that may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said method comprising the steps of: (a) estimating a wind speed at the present time; (b) estimating a rotor speed at the present time; (c) applying said wind speed and said rotor speed to estimate an amount of driving torque applied to the rotor at the present time; (d) applying said estimated driving torque to predict a wind speed average over the swept area at a subsequent point in time; (e) applying said wind speed predicted at said subsequent point in time to select a desired rotor speed for said subsequent point in time; (f) applying said desired rotor speed to select a control parameter that can be applied to said rotor speed control so that said desired rotor speed will be approximated by the actual rotor speed; and (g) at said subsequent point in time, repeating steps (a)-(f), applying the wind speed predicted for said subsequent point in time as the wind speed estimate for the present time in the step (a).
Claim 74
Independent Claim
231 words
A method for supplying a control parameter to control a variable speed electrical generator in a wind turbine having rotor speed control dependent upon said control parameter, the wind turbine having at least one aerodynamic surface sweeping a swept area that presents a cross-section to a wind that may vary over time, the wind turbine converting the wind energy into a driving torque applied to a generator rotor, said method comprising the steps of: (a) estimating a wind speed at the present time; (b) estimating a rotor speed at the present time; (c) applying said wind speed and said rotor speed to estimate an amount of driving torque applied to the rotor at the present time; (d) applying said estimated driving torque to predict a wind speed average over the swept area at a subsequent point in time; (e) applying said wind speed predicted at said subsequent point in time to select a desired rotor speed for said subsequent point in time; (f) applying said desired rotor speed to select a control parameter that can be applied to said rotor speed control so that said desired rotor speed will be approximated by the actual rotor speed; and (g) at said subsequent point in time, repeating steps (a)-(f), applying the wind speed predicted for said subsequent point in time as the wind speed estimate for the present time in the step (a).
Claim 75
Dependent Claim
46 words
The control method of claim 62 wherein the method of steps (a)-(g) is continuously repeated at selected time intervals so that the wind speed prediction is updated for each time interval, and the rotor speed is controlled at each time interval to track the wind speed.
Claim 76
Dependent Claim
59 words
The control method of claim 62, further comprising the steps of: (h) calculating a first correction term dependent upon said amount of driving torque estimated for the present time; and (i) adding the estimated wind speed for the present point in time to said first correction term, to predict the wind speed average for said subsequent point in time.
Claim 77
Dependent Claim
83 words
The control method of claim 64, further comprising the steps of: (j) sensing a sensed rotor speed at the present time; (k) calculating a rotor speed error at the present time as the difference between the sensed rotor speed and the predicted rotor speed; (l) calculating a second correction term based upon said rotor speed error; and (m) adding the second correction term to the wind speed predicted in the step (g), to predict the wind speed for said subsequent point in time.
Claim 78
Dependent Claim
43 words
The control method of claim 62 wherein the step (f), applying said desired rotor speed to select a control parameter, further comprises the step of: (h) calculating a reference load torque to be applied to the generator at said subsequent point in time.
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