Methods and systems to operate a wind turbine system using a non-linear damping model

Patent metadata

Field	Value
Publication number	US-9587629-B2
Application number	US-201414319269-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Jun 30, 2014
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A wind turbine system is presented. The wind turbine system includes a tower, a plurality of blades, a rotor supported by the tower and rotatably coupled to the plurality of blades, a control unit programmed to predict a net energy of the tower at one or more future points in time, and if the predicted net energy is within a design limit, then continue with baseline operating control models for normal operation of the wind turbine system, if the predicted net energy exceeds the design limit, then use a non-linear tower damping model to generate tower damping commands to control tower damping of the wind turbine system.

First claim

The invention claimed is:

1. A wind turbine system, comprising:
a tower having at least one sensor mounted thereon;
a plurality of blades;
a rotor supported by the tower and rotatably coupled to the plurality of blades;
a control unit programmed to:
determine a current deflection of the tower, a current fore-aft velocity of the tower, and a current acceleration of the tower based on information sensed by the at least one sensor;
determine a predicted deflection of the tower as a function of the current deflection of the tower, the current fore-aft velocity of the tower and the current acceleration of the tower;
determine a predicted tower-load-moment indicative parameter of the tower, wherein the predicted tower-load-moment indicative parameter comprises a predicted net energy of the tower, where a net energy of the tower includes a net potential energy of the tower, a net kinetic energy of the tower, or a total of the net potential energy of the tower and the net kinetic energy of the tower; and
compare the predicted tower-load-moment indicative parameter of the tower to a design limit,

wherein, if the predicted tower-load-moment indicative parameter is within the design limit, then a baseline operating control model is used by the control unit for normal operation of the wind turbine system; and
wherein, if the predicted tower-load-moment indicative parameter exceeds the design limit, then a non-linear tower damping model is used by the control unit to determine a non-linear variable damping coefficient to prevent damage to the tower; and
wherein the non-linear damping model is configured to generate a tower damping command in phase with the current fore-aft velocity of the tower; and
wherein the tower damping command comprises a blade pitch angle alteration command.

2. The wind turbine system of claim 1 , wherein the blade pitch angle alteration command is determined by the following equation:

θ
add

=

Ϛ
*
ω
*

X
.

0

*

M
/

(

∂

Fz
Aero

∂
θ

)

where,
θ add is the blade pitch angle alteration command;
ζ is the non-linear variable damping coefficient;
φ is a natural frequency of the tower;
{dot over (X)} 0 is the current fore-aft velocity of the tower;
M is a modal mass of the tower;
Fz Aero is an aerodynamic rotor thrust; and

∂

Fz
Aero

∂
θ

is a sensitivity of the aerodynamic rotor thrust with respect to a pitch angle, θ, of the plurality of blades.

3. The wind turbine system of claim 2 , wherein the blade pitch angle alteration command comprises a collective pitch angle alteration command for all of the plurality of blades.

4. The wind turbine system of claim 2 , wherein the blade pitch angle alteration command comprises an individual pitch angle alteration command for each of the plurality of blades.

5. The wind turbine system of claim 1 , wherein the blade pitch angle alteration command is determined by the following equation:

θ
add

=

θ
rate

T
left

where,
θ add is the blade pitch angle alteration command;
θ rate is a pitch rate to prevent damage to the tower; and
T left is a remaining amount of time before damage occurs to the tower.

6. A wind turbine system, comprising:
a tower having at least one sensor mounted thereon;
a plurality of blades;
a rotor supported by the tower and rotatably coupled to the plurality of blades;
a control unit programmed to:
determine a current fore-aft deflection of the tower, a current fore-aft velocity of the tower, and a current fore-aft acceleration of the tower based on information sensed by the at least one sensor;
determine a predicted deflection of the tower as a function of the current fore-aft deflection of the tower, the current fore-aft velocity of the tower and the current acceleration of the tower;
determine a predicted net energy of the tower, wherein a net energy of the tower comprises a net potential energy of the tower, a net kinetic energy of the tower, or a total of the net potential energy of the tower and the net kinetic energy of the tower; and
compare the predicted net energy of the tower to a design limit,

wherein, if the predicted net energy is within the design limit, then a baseline operating control model is used by the control unit for normal operation of the wind turbine system; and
wherein, if the predicted net energy exceeds the design limit, then a non-linear tower damping model is used by the control unit to determine a non-linear variable damping coefficient to prevent damage to the tower,
wherein the non-linear variable damping coefficient is a function of an energy reduction factor and a remaining amount of time before damage occurs to the tower,
wherein the energy reduction factor is determined using the following equation:
E ratio =R predicted /R max

where,
E ratio is the energy reduction factor;
R predicted is the predicted net energy of the tower; and
R max is the design limit.

7. The wind turbine system of claim 6 , wherein the design limit, R max , comprises a maximum potential energy of the tower at a maximum tower deflection limit of the tower.

8. The wind turbine system of claim 6 , wherein the predicted net energy is determined by the following equation:
R predicted =√{square root over ((ω Y dim ) 2 +X dim 2 )}

where,
R predicted is the predicted net energy of the tower;
ω is a natural frequency of the tower;
Y dim is a first dimensionless parameter; and
X dim is a second dimensionless parameter.

9. The wind turbine system of claim 8 , wherein the first dimensionless parameter, Y dim , is determined by the following equation:

Y
dim

=

ω
⁢

y
predicted

-

Fz
aero

/

Assignees

• Gen Electric

Inventors

• Deshpande Ameet Shridhar
• Agarwal Pranav

Classifications

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title

• F03D9/002

  Mechanical Engineering · mapped topic

• F05B2260/821

  Parameter estimation or prediction · CPC title

• F03D7/045

  with model-based controls · CPC title

• Y02E10/723

  Cross-Sectional Technologies · mapped topic