HYBRID BRAKING SYSTEM AND METHOD

• US 20100133823A1
• Filed: 09/25/2009
• Published: 06/03/2010
• Est. Priority Date: 09/25/2009
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Sihler, Christof Martin, Schramm, Simon Herbert
• Granted Patent: US 8,080,891 B2
• Time in Patent Office: Days
• US Class Current: 290/44
• CPC Class Codes: F03D 7/0248 by mechanical means acting on the power train
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 9/102 for limiting effects of transients
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A wind turbine hybrid braking system is presented. The system includes a generator coupled to a main shaft of the wind turbine for generating and transmitting power. A mechanical brake is coupled to the main shaft for applying reaction torque upon braking of the wind turbine. The system further includes an electrical braking circuit coupled to the generator for acting in conjunction with the mechanical brake and dissipating active power via controlled switching.

Claims

1. A wind turbine hybrid braking system comprising:

a generator coupled to a main shaft of the wind turbine for generating and transmitting power;

a mechanical brake coupled to the main shaft for applying reaction torque upon braking of the wind turbine; and

an electrical braking circuit coupled to the generator for acting in conjunction with the mechanical brake and dissipating active power via controlled switching.

2. The system of claim 1, wherein the electrical braking circuit is coupled to an output side of the generator.

3. The system of claim 1, wherein the electrical braking circuit further comprises at least one controllable semiconductor switch and at least one power resistor.

4. The system of claim 3, wherein the at least one semiconductor switch comprises an insulated-gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), an integrated gate commutated thyristor (IGCT), a thyristor, or combinations thereof.

5. The system of claim 1, further comprising at least one sensor coupled to the main shaft.

6. The system of claim 5, wherein the sensor is configured to measure at least one mechanical parameter of the main shaft.

7. The system of claim 5, further comprising a controller for activating both the mechanical brake and the electrical braking circuit in response to an emergency stop signal.

8. The system of claim 7, wherein the controller is configured for causing the electrical braking circuit to damp a dynamic torque on the main shaft in response to the activation of the mechanical break.

9. A method to dampen dynamic torque on a shaft of a wind turbine, the method comprising, upon receipt of an emergency stop signal, simultaneously mechanically braking the shaft and activating a controllable switch of an electrical braking circuit to dissipate active power from the wind turbine in a power resistor of the electrical braking circuit.

10. The method of claim 9, further comprising monitoring at least one mechanical parameter of the shaft.

11. The method of claim 10, wherein the mechanical parameter comprises at lease one of torque, rotational speed, or combinations thereof.

12. The method of claim 10, further comprising computing the amount of active power to be dissipated.

13. The method of claim 9, further comprising activating the controllable switch via a controller coupled to the electrical braking circuit.

14. A hybrid braking system comprising:

a mechanical brake coupled to a main shaft of a turbine;

an electrical braking circuit comprising;

at least one semiconductor switch,

a switching control circuit,

at least one power resistor for dissipating active power,

a controller for activating both the mechanical brake and the electrical braking circuit in response to an emergency stop signal.

15. The system of claim 14, wherein hybrid braking is configured to reduce a torsional oscillation in the main shaft.

16. The system of claim 14, wherein the power resistor is configured for a thermal capacity of about less than 5 percent of design value of energy to be dissipated in the mechanical brake.

17. The system of claim 14 further comprising at least one sensor configured to measure at least one mechanical parameter of the main shaft.

18. The system of claim 17, wherein the at least one sensor is coupled to the switching control circuit.

19. The system of claim 17, wherein the at least one mechanical parameter comprises rotational speed, torque, or combinations thereof.