METHOD AND SYSTEM FOR CONTROLLED SHUTDOWN OF WIND TURBINES

• US 20140339829A1
• Filed: 12/07/2012
• Published: 11/20/2014
• Est. Priority Date: 12/08/2011
• Status: Active Grant

• Current Assignee: Vestas Wind Systems A/S
• Original Assignee: Vestas Wind Systems A/S
• Inventors: Doan, Duy Duc
• Granted Patent: US 9,574,548 B2
• Time in Patent Office: Days
• US Class Current: 290/44
• CPC Class Codes: F03D 7/0244 for braking
• CPC Class Codes: F03D 7/0264 for stopping; controlling in emergency situations orientating out of wind F03D7/0208
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: F03D 7/0296 to prevent, counteract or reduce noise emissions
• CPC Class Codes: F03D 9/11 storing electrical energy
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor
• CPC Class Codes: H02P 9/08 Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

The present invention relates to a method for controlled shutdown of wind turbines. The method involves using a generator side converter, and optionally a DC chopper, as a generator load during controlled shutdown. In this way gearbox back-lashing and drive train oscillations can be avoided. The present invention also relates to a wind turbine capable of performing controlled shutdown in accordance with the before-mentioned method.

Claims

1. A method for shutting down a wind turbine comprising

a power generator being connected to a set of rotatable rotor blades via a drive train,

a power converter comprising generator side and grid side converters being separated by an intermediate DC circuit, and

power dissipation or power storage means being operatively connected to the intermediate DC circuit

the method comprising:

operating the generator side converter as a generator load in a manner so that torque of the drive train has a constant direction during shutdown of the wind turbine.

2. A method according to claim 1, wherein the load of the generator side converter is applied in accordance with a power reference derived from a generator torque-speed curve.

3. A method according to claim 1, further comprising the step of dissipating or storing a controlled amount of excess power in the power dissipation or power storage means in a manner so that the drive train torque has a constant direction during shutdown of the wind turbine.

4. A method according to claim 1, the generator side converter is applied as a generator load when the drive train torque is below a predetermined limit.

5. A method according to claim 1, further comprising the step of setting the grid side converter in an inactive mode of operation.

6. A method according to claim 5, further comprising the step of disconnecting the wind turbine from an associated grid.

7. A wind turbine comprising

a power generator being connected to a set of rotatable rotor blades via a drive train,

a power converter comprising generator side and grid side converters being separated by an intermediate DC circuit, and

power dissipation or power storage means being operatively connected to the intermediate DC circuit

wherein the generator side converter is adapted to be applied as a generator load in a manner so that the drive train torque has a constant direction during shutdown of the wind turbine.

8. A method according to claim 7, wherein the load of the generator side converter is applied in accordance with a power reference derived from a generator torque-speed curve.

9. A wind turbine according to claim 7, wherein the power dissipation or power storage means is adapted to receive a controlled amount of excess power so that the drive train torque has a constant direction during shutdown of the wind turbine.

10. A wind turbine according to claim 7, wherein the power dissipation or power storage means comprises a resistor, a capacitor or a battery.

11. A wind turbine according to claim 7, wherein the drive train comprises a gearbox.