Method and system for braking in a wind turbine
A braking system for a wind turbine is provided. The system includes one or more motors for driving a part of the wind turbine, a first group of brakes for braking the part of the wind turbine, and a second group of brakes for braking the part of the wind turbine. The first group of brakes is in a normally closed condition and the second group of brakes is in a normally open condition, so that a default brake torque can be selectively chosen that is less than a maximum brake torque.
1. A braking system in a wind turbine, the braking system comprising:
one or more motors for driving a part of the wind turbine;
a first group of one or more brakes for braking the part of the wind turbine, each brake in the first group of one or more brakes having a normally-closed default state;
a second group of one or more brakes for braking the part of the wind turbine, each brake in the second group of one or more brakes having a normally-open default state;
wherein the first group of one or more brakes is in a normally closed condition and the second group of one or more brakes is in a normally open condition, so that a default brake torque can be selectively chosen that is less than a maximum brake torque.
2. The braking system of claim 1 , wherein the one or more motors comprise a pitch drive.
3. The braking system of claim 2 , wherein the part of the wind turbine is a rotor blade.
4. The braking system of claim 1 , wherein one or more motors comprise a yaw drive.
5. The braking system of claim 4 , wherein the part of the wind turbine is a nacelle.
6. The braking system of claim 1 , wherein during a grid loss event the first group of one or more brakes is in a normally closed condition and the second group of one or more brakes is in a normally open condition.
7. The braking system of claim 6 , wherein during a grid available condition the first group of one or more brakes and the second group of one or more brakes are in a like condition.
8. The braking system of claim 1 , wherein an actuator in the wind turbine exerts an increasing torque as the actuator speed increases.
9. The braking system of claim 8 , wherein a pitch drive comprises the actuator, and the pitch drive is capable of rotating a rotor blade relative to a hub.
10. The braking system of claim 8 , wherein a yaw drive comprises the actuator, and the yaw drive is capable of rotating a nacelle of the wind turbine relative to a tower of the wind turbine.
11. A wind turbine comprising:
a tower;
a nacelle mounted on the tower;
a rotor having a hub and one or more rotor blades;
a brake system for controlling one or more brakes, the system comprising:
one or more motors for driving a part of the wind turbine;
a first group of the one or more brakes for braking the part of the wind turbine, each brake in the first group of one or more brakes having a normally-closed default state;
a second group of the one or more brakes for braking the part of the wind turbine, each brake in the second group of one or more brakes having a normally-open default state;
wherein the first group of the one or more brakes is in a normally closed condition and the second group of the one or more brakes is in a normally open condition, so that a default brake torque can be selectively chosen that is less than a maximum brake torque.
12. The wind turbine of claim 11 , wherein the one or more motors comprise at least one of a pitch drive, and a yaw drive.
13. The wind turbine of claim 12 , wherein the part of the wind turbine is at least one of the one or more rotor blades, and the nacelle.
14. The wind turbine of claim 11 , wherein during a grid loss event the first group of the one or more brakes is in a normally closed condition and the second group of the one or more brakes is in a normally open condition; and
wherein during a grid available condition the first group of the one or more brakes and the second group of the one or more brakes are in a like condition.
15. The wind turbine of claim 11 , wherein an actuator in the wind turbine exerts an increasing torque as the actuator speed increases.
16. The wind turbine of claim 15 , wherein a pitch drive comprises the actuator, and the pitch drive is capable of rotating a rotor blade relative to a hub.
17. The wind turbine of claim 15 , wherein a yaw drive comprises the actuator, and the yaw drive is capable of rotating a nacelle of the wind turbine relative to a tower of the wind turbine.