Variable speed wind turbine having a passive grid side rectifier with scalar power control and dependent pitch control

• US 20040217594A1
• Filed: 06/01/2004
• Published: 11/04/2004
• Est. Priority Date: 02/11/2002
• Status: Active Grant

• Current Assignee: Vestas Wind Systems A/S
• Original Assignee: Vestas Wind Systems A/S
• Inventors: Siebenthaler, Eckardt, Andresen, Bjorn, Feddersen, Lorenz
• Granted Patent: US 6,933,625 B2
• Time in Patent Office: Days
• US Class Current: 290/44
• CPC Class Codes: F03D 15/10 using gearing not limited to rotary motion, e.g. with oscillating or reciprocating members
• CPC Class Codes: F03D 7/0224 Adjusting blade pitch
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F05B 2270/1016 in variable speed operation
• CPC Class Codes: F05B 2270/20 to optimise the performance of a machine
• CPC Class Codes: F05B 2270/32 Wind speeds
• CPC Class Codes: F05B 2270/327 Rotor or generator speeds
• CPC Class Codes: F05B 2270/328 Blade pitch angle
• CPC Class Codes: F05B 2270/337 Electrical grid status parameters, e.g. voltage, frequency or power demand
• CPC Class Codes: F05B 2270/705 proportional-integral
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A variable speed wind turbine having a passive grid side rectifier using scalar power control and dependent pitch control is disclosed. The variable speed turbine may include an electrical generator to provide power for a power grid and a power conversion system coupled to the electrical generator. The power conversion system may include at least one passive grid side rectifier. The power conversion system may provide power to the electrical generator using the passive grid side rectifier. The variable speed wind turbine may also use scalar power control to provide more precise control of electrical quantities on the power grid. The variable speed wind turbine may further use dependent pitch control to improve responsiveness of the wind turbine.

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40. A variable speed wind turbine comprising:

an electrical generator including a rotor and a stator to generate electrical power; and

a power converter coupled to the electrical generator, the power converter having at least a passive grid side rectifier, and

wherein the stator supplies electric power to a power grid through a Δ

connection or a Y connection and the rotor receives slip or excitation power from the power grid through the passive grid side rectifier of the power converter.

41. The variable speed wind turbine of claim 40, wherein the electrical generator selectively provides electrical power to the power grid through the stator via the Δ

connection or the Y connection.

42. The variable speed wind turbine of claim 40, wherein the rotor of the electrical generator directs excess generated electrical power to the power converter.

43. The variable speed wind turbine of claim 40, wherein the passive grid side rectifier comprises power diodes.

44. The variable speed wind turbine of claim 43, wherein the power diodes are connected in a three phase bridge configuration.

45. The variable speed wind turbine of claim 40, wherein the passive grid side rectifier converts fixed frequency AC signals from the power grid into a DC voltage at below synchronous speed.

46. The variable speed wind turbine of claim 40, wherein the passive grid side rectifier prevents power being supplied to the power grid from the power converter at above synchronous speed.

47. A method for a variable speed wind turbine comprising:

converting mechanical energy generated by wind blades into electrical power by a rotor of an electrical generator;

selecting a Δ

connection or a Y connection for supplying the electrical power to a power grid via a stator of the electrical generator; and

receiving slip or excitation power by the rotor from the power grid via a passive grid side rectifier of a power converter.

48. The method of claim 47, further comprising:

selectively selecting the Δ

connection or the Y connection for supplying the electrical power to the power grid via the stator of the electrical generator.

49. The method of claim 47, further comprising:

directing excess generated power to the power converter by the rotor of the electrical generator.

50. The method of claim 47, receiving slip or excitation power includes receiving slip or excitation power by the rotor at below synchronous speed.

51. The method of claim 47, further comprising:

preventing power from being supplied to the power grid via the power converter by the passive grid side rectifier.