Variable speed wind turbine having a matrix converter

• US 6,566,764 B2
• Filed: 05/23/2001
• Issued: 05/20/2003
• Est. Priority Date: 05/23/2000
• Status: Active Grant

• Current Assignee: Vestas Wind Systems A/S
• Original Assignee: Vestas Wind Systems A/S
• Inventors: Helle, Lars, Rebsdorf, Anders V.
• Primary Examiner(s): Ponomarenko; Nicholas
• Application Number:
  US09/862,316
• Publication Number:
  US 20020079706A1
• Time in Patent Office: 727 Days
• Field of Search: 290/43,44,54,55 322/29,32 363/13,157,159
• US Class Current: 290/44
• CPC Class Codes: F03D 7/0284 in relation to the state of the electric grid
• 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: H02M 1/42 Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
• CPC Class Codes: H02M 5/297 for conversion of frequency
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 9/007 Control circuits for doubly fed generators
• CPC Class Codes: H02P 9/42 to obtain desired frequency without varying speed of the generator
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects

Abstract

A variable speed wind turbine is disclosed comprising a turbine rotor that drives a doubly-fed induction generator, a matrix converter which converts variable frequency output into constant frequency output, and a control unit and a protection circuit for the matrix converter. Power is circulated in the system allowing for sensorless detection of rotor position and better output ratios of power from the system.

Claims

1. A variable speed wind turbine, comprising:

a turbine rotor including at least one blade mounted to a rotatable turbine shaft;

an induction generator having a stator and a rotor coupled to the turbine shaft for rotation therewith;

a matrix converter including an array of switching elements;

a matrix converter control unit to control the switching elements; and

a protection circuit for protecting the matrix converter against over voltages.

2. A turbine according to claim 1, having a voltage gradient limiting circuit located between the matrix converter and the generator rotor.

3. A turbine according to claim 2, wherein the voltage gradient limiting circuit includes an inductance.

4. A turbine according to claim 2, wherein the voltage gradient limiting circuit includes an inductance capacitor filter.

5. A turbine according to claim 1, including a transformer with at least three windings including a tertiary winding;

and

means for adjusting voltage at the tertiary winding, wherein a ratio of the input potential to the output potential is greater than 0.866.

6. A turbine according to claim 1, including a generator with a winding ratio;

and means for adjusting the winding ratio of the generator wherein a reduced matrix converter gain is overcome, wherein a ratio of the input potential to the output potential is greater than 0.866 and whereby a current rating of the switching elements is increased.

7. A turbine according to claim 1, having a protection circuit for protecting the matrix converter against over voltages and for retaining control after a grid disruption.

8. A turbine of claim 1, having means for position sensorless detection of the position of said turbine rotor.

9. A turbine according to claim 8, further including the measurement of the current of said rotor.

10. A turbine according to claim 8, further including the circulation of reactive power.

11. A turbine according to claim 1, having a power controller for circulating reactive energy.

12. A turbine according to claim 1, having a power controller for controlling the power factor of the turbine without impacting the circulation of reactive power.

13. A turbine according to claim 1, wherein at least one of said switching elements comprises a standard H-Bridge module.

14. A turbine according to claim 1, wherein said stator further includes a stator winding means for shifting between a Y-connection and a Δ

-connection.

15. A turbine according to claim 1, which further includes a means for the facilitating the active damping of current harmonics.

16. A turbine according to 1, which further includes a means for facilitating the active damping of resultant drive-train oscillations.

17. A turbine according to claim 1, wherein the induction generator is a doubly-fed induction generator.

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

supplying power from an induction generator to a power grid using a matrix converter including using a protection circuit for protecting the matrix converter from over voltages.

19. The method of claim 18, wherein the protection circuit retains control of the matrix converter after grid disruption.

20. The method of claim 18, wherein the power is supplied from a doubly-fed induction generator.