CONTROL SYSTEM FOR WIND ENERGY CONVERTERS

• US 20100102558A1
• Filed: 01/29/2009
• Published: 04/29/2010
• Est. Priority Date: 03/31/2008
• Status: Active Grant

• Current Assignee: AMSC Austria GmbH
• Original Assignee: Amsc Windtec GmbH (American Superconductor Corporation)
• Inventors: Weichbold, Peter, Tratnig, Robert
• Granted Patent: US 8,154,143 B2
• Time in Patent Office: Days
• US Class Current: 290/44
• CPC Class Codes: F03D 15/00 Transmission of mechanical power
• CPC Class Codes: F03D 15/10 using gearing not limited to rotary motion, e.g. with oscillating or reciprocating members
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F05B 2260/40311 of the epicyclic, planetary or differential type
• CPC Class Codes: F05B 2270/1011 to prevent overspeed
• CPC Class Codes: F05B 2270/304 Spool rotational speed
• CPC Class Codes: F05B 2270/309 Rate of change of parameters
• CPC Class Codes: F16H 2037/0866 Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
• CPC Class Codes: F16H 47/04 the mechanical gearing being of the type with members having orbital motion
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A wind energy converter configured for transmitting power to an electric grid includes a variable ratio gear system mechanically coupled between a rotor and a generator. A control system is configured to mechanically control a rotational speed of the generator so that, during a low voltage event, the wind energy converter can continue to operate and supply power to the grid.

Claims

1. A wind energy converter configured for transmitting power to an electric grid, the wind energy converter comprising:

a variable ratio gear system mechanically coupled between a rotor and a generator of the wind energy converter

the variable ratio gear system including at least one shaft coupled to the generator and a hydraulic circuit having a hydraulic unit mechanically coupled to the shaft, the hydraulic circuit providing a hydraulic pressure; and

a control system configured to control a rotational speed of the generator by determining, on the basis of the hydraulic pressure, a desired configuration of the hydraulic unit associated with a prescribed generator speed.

7. The wind energy converter of claim 1 wherein the control system includes a pressure controller configured to provide a desired hydraulic pressure signal indicative of a desired hydraulic pressure associated with the prescribed generator speed.

8. The wind energy converter of claim 1 wherein the hydraulic circuit further includes a second hydraulic unit, and the control system determines a desired configuration of the second hydraulic unit on the basis of a rotor speed.

16. The wind energy converter of claim 1 wherein the variable ratio gear system includes:

a first shaft mechanically coupled to the rotor;

a second shaft mechanically coupled to the hydraulic circuit; and

a third shaft mechanically coupled to the hydraulic circuit and the generator.

17. The wind energy converter of claim 16 wherein the variable ratio gear system further includes:

a gear box mechanically coupled between the first shaft an the rotor, the gear box configured to give a constant gear ratio;

a first spur gear mechanically coupled between the gear box and the first shaft;

a second spur gear mechanically coupled between the hydraulic circuit and the second shaft; and

a third spur gear mechanically coupled between the hydraulic circuit and the third shaft.

18. The wind energy converter of claim 1 wherein the hydraulic circuit is a hydrostatic circuit.

19. The wind energy converter of claim 1 wherein the hydraulic circuit is a hydrodynamic circuit.

2-6. -6. (canceled)

9-15. -15. (canceled)

20. A method for operating a wind energy converter configured for transmitting power to an electric grid, the wind energy converter comprising a variable ratio gear system mechanically coupled between a rotor and a generator of the wind energy converter, the variable ratio gear system including at least one shaft coupled to the generator and a hydraulic circuit having a hydraulic unit mechanically coupled to the shaft, the hydraulic circuit providing a hydraulic pressure, the method comprising:

controlling a rotational speed of the generator by determining, on the basis of the hydraulic pressure, a desired configuration of the hydraulic unit associated with a prescribed generator speed.

21. The method of claim 20, further comprising:

providing a desired hydraulic pressure signal indicative of a desired hydraulic pressure associated with the prescribed generator speed;

receiving an actual hydraulic pressure signal indicative of an actual hydraulic pressure; and

computing a pressure error signal between the desired and actual hydraulic pressure signals.

22. The method of claim 21, further comprising:

computing, on the basis of the pressure error signal, a first parameter of the desired configuration of the hydraulic unit.

23. The method of claim 22, further comprising:

receiving an offset signal; and

computing a second parameter of the desired configuration of the hydraulic unit on the basis of the offset signal and the first parameter.

24. The method of claim 23, wherein the desired configuration of the hydraulic unit is determined on the basis of the first and second parameters.

25. The method of claim 23, wherein the first and second parameters are responsive to a change in the rotational speed of the generator.

26. The method of claim 23, wherein the second parameter conforms with a predetermined limitation.

27. The method of claim 26, wherein the predetermined limitation includes a limitation on a rate of change in the second parameter.