System and method for braking a wind turbine rotor at an overspeed condition

• US 9,759,192 B2
• Filed: 08/16/2012
• Issued: 09/12/2017
• Est. Priority Date: 08/16/2012
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Perley, Thomas Franklin, Gerber, Brandon Shane, Yarbrough, Aaron
• Primary Examiner(s): Fristoe, Jr., John K
• Assistant Examiner(s): Brownson, Jeffrey A
• Application Number:
  US13/587,133
• Publication Number:
  US 20140050579A1
• Time in Patent Office: 1,853 Days
• Field of Search: None
• CPC Class Codes: F03D 7/0244 for braking
• CPC Class Codes: F03D 7/0248 by mechanical means acting on the power train
• CPC Class Codes: F03D 7/0252 with aerodynamic drag devices on the blades
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A system and method for braking a wind turbine includes monitoring rotation of the wind turbine generator rotor. A braking torque is applied to reduce the rotational speed of the rotor at a first setpoint rotational speed. The braking torque is proportionally increased as the rotational speed of the rotor increases beyond the first detected setpoint rotational speed up to a maximum braking torque.

Claims

1. A wind turbine, comprising:

a hub with a plurality or rotor blades configured thereon, said hub connected to a generator rotor via a drive train;

a sensor disposed to monitor rotation of said rotor;

a brake configured along the drive train between the hub and the generator to reduce the rotational speed of said rotor;

a brake control system operatively coupled to said brake and said sensor, said brake control system configured to apply a braking torque to said rotor via said brake at a first setpoint rotational speed and to proportionally increase the braking torque as the detected rotational speed of said rotor increases beyond the first detected setpoint rotational speed; and

wherein the first setpoint rotational speed is defined above a rated rotor speed for said wind turbine, said brake control system configured to initially apply the braking torque to said rotor at the first setpoint rotational speed and to increase the braking torque up to a full braking torque applied at a second setpoint rotational speed prior to said rotor reaching a fault rotational speed.

2. The wind turbine as in claim 1, wherein the first setpoint rotational speed is between rated speed and 103% of rated speed and said second setpoint rotational speed is less than 110% of rated speed.

3. The wind turbine as in claim 1, wherein said brake control system is configured to apply the increasing braking torque as a linear function of increasing rotor rotational speed.

4. The wind turbine as in claim 1, wherein said brake control system is configured to apply the increasing braking torque as an exponential function of increasing rotor rotational speed.

5. The wind turbine as in claim 1, wherein said brake is a hydraulic brake.

6. A method for controlling rotational speed of a wind turbine in an over speed condition, comprising:

monitoring rotation of a wind turbine generator;

applying a braking torque to the rotor at a first setpoint rotational speed with a brake configured along the drive train between the hub and the generator;

proportionally increasing the braking torque with the brake as a function of rotor rotational speed as the rotational speed of the rotor increases beyond the first setpoint rotational speed; and

wherein the first setpoint rotational speed is defined above a rated rotor seed for the wind turbine, and further comprising increasing the braking torque from an initial value at the first setpoint rotational speed up to a full braking torque applied at a second setpoint rotational speed prior to the rotor reaching a fault rotational speed.

7. The method as in claim 6, wherein the first setpoint rotational speed is between rated speed and 103% of rated speed and the second setpoint rotational speed is less than 110% of rated speed.

8. The method as in claim 6, wherein the braking torque is increased as a linear function of increasing rotor rotational speed between the first and second setpoint rotational speeds.

9. The method as in claim 6, wherein the braking torque is increased as an exponential function of increasing rotor rotational speed between the first and second setpoint rotational speeds.

10. The method as in claim 6, wherein the braking torque is applied with a hydraulic brake.

11. The method as in claim 6, comprising applying an aerodynamic braking torque to the rotor in conjunction a mechanical braking torque.

12. The method as in claim 11, wherein the first setpoint rotational speed is defined above a rated rotor speed for the wind turbine, and further comprising increasing the braking torque to the rotor from an initial value at the first setpoint rotational speed up to a full braking torque applied at a second setpoint rotational speed prior to the rotor reaching a fault rotational speed.

13. The method as in claim 12, comprising increasing the aerodynamic braking torque as a function of increasing rotor rotational speed between the first and second rotational setpoint rotational speeds.

14. The method as in claim 13, wherein the aerodynamic braking torque is increased linearly or exponentially between the first and second rotational setpoint rotational speeds.