Wind Converter Control for Weak Grid

• US 20170302204A1
• Filed: 04/14/2016
• Published: 10/19/2017
• Est. Priority Date: 04/14/2016
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (GE Vernova, Inc.)
• Original Assignee: General Electric Company
• Inventors: Yuan, Zhihui, Roesner, Robert, Schroeder, Stefan, Panosyan, Ara, Anaparthi, Krishna Kumar
• Granted Patent: US 9,970,417 B2
• Time in Patent Office: Days
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F03D 9/257 the wind motor being part of a wind farm
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 3/381 Dispersed generators
• 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
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects

Abstract

This disclosure relates to systems and methods for controlling a wind converter for a weak electrical grid. In one embodiment of the disclosure, a system for controlling the wind converter includes a wind converter connected to an electrical grid at a point of connection (POC) and operable to transfer a power to the electrical grid. The system includes a first control loop operable to calculate, based on electrical grid parameters and wind converter characteristics, a voltage reference to be generated by the wind converter. The system includes a second control loop to convert, based on the electrical grid parameters, the voltage reference into a current reference. The second loop converts the angle information of the voltage reference into a voltage at the POC. The system includes a third control to regulate, based at least on the current reference, the power transferred by the wind converter to the electrical grid.

Claims

1. A system comprising:

a wind converter connected to an electrical grid at a point of connection (POC) and operable to transfer a power to the electrical grid;

a first control loop operable to;

calculate, based at least on electrical grid parameters and wind converter characteristics, a voltage reference to be generated by the wind converter;

a second control loop operable to;

convert, based at least on the electrical grid parameters,

the voltage reference into a current reference, the current reference associated with an angle information; and

a third control loop operable to regulate, based at least on the current reference, the power transferred by the wind converter to the electrical grid.

2. The system of claim 1, wherein:

the second loop is further operable to convert the angle information into a voltage at the POC; and

the third control loop is further operable to regulate the power based on the voltage at the POC.

3. The system of claim 2, wherein the third control loop is operable to regulate the power using a rotation frame reference generated by a phase lock loop based on the voltage at the POC.

4. The system of claim 1, wherein the electrical grid parameters include at least a short circuit ratio.

5. The system of claim 1, wherein the electrical grid parameters include an estimated voltage of the electrical grid.

6. The system of claim 1, wherein the wind converter characteristics include a voltage magnitude at the POC and a DC link voltage of the wind converter.

7. The system of claim 6, wherein the first control loop is operable to calculate the voltage reference based at least on the POC voltage magnitude and the wind converter DC link voltage.

8. The system of claim 1, wherein the current reference includes at least one of an active current reference and a reactive current reference.

9. The system of claim 1, wherein the current reference corresponds to a power angle reference associated with the voltage at POC.

10. A method for controlling a wind converter, the method comprising:

estimating parameters of an electrical grid, the electrical grid being connected to the wind converter at a point of connection (POC) and the wind converter being operable to transfer a power to the electrical grid;

acquiring characteristics of the wind converter;

calculating, based at least on the electrical grid parameters and the wind converter characteristics, voltage reference to be generated by the wind converter;

translating the wind converter voltage reference into a current reference, the current reference being associated with angle information;

translating the angle information into a voltage at the POC; and

regulating, based at least on the current reference, the power transferred by the wind converter to an electrical grid.

11. The method of claim 10, wherein the power is further regulated based on a rotation frame reference.

12. The method of claim 11, wherein the rotation frame reference is generated by a phase lock loop based on a voltage of the current measured at the POC.

13. The method of claim 10, wherein the estimated electrical grid parameters include at least a short circuit ratio.

14. The method of claim 10, wherein the estimated electrical grid parameters include at least an estimated voltage of the current of the electrical grid.

15. The method of claim 10, wherein the wind converter characteristics include a voltage magnitude at the POC and a DC link voltage of the wind converter.

16. The method of claim 15, wherein the first control loop is operable to calculate the voltage reference based at least on the POC voltage magnitude and the wind converter DC link voltage.

17. The method of claim 10, wherein the current reference includes at least one of an active current reference and a reactive current reference.

18. The method of claim 10, wherein the current reference corresponds to a power angle reference associated with the voltage at the POC.

19. A system comprising:

a wind farm in communication with an electrical grid, the wind farm comprising at least one wind converter;

the at least one wind converter connected to the electrical grid at a point of connection (POC) and operable to transfer a current to the electrical grid;

a first control loop operable to;

calculate, based at least on electrical grid parameters and wind converter characteristics, a voltage reference to be generated by the at least one wind converter, wherein the electrical grid parameters include a short circuit ratio and an estimated voltage of the electrical grid and the at least one wind converter characteristics include a voltage magnitude at the POC and a DC link voltage of the at least one wind converter;

a second control loop operable to;

convert, based at least on the electrical grid parameters, the voltage reference into a current reference, the current reference including at least one of an active current reference and a reactive current reference and associated with an angle information; and

convert, the angle information into a voltage at the POC; and

a third control loop operable to regulate, based at least on the current reference and a rotation frame reference, the power transferred by the at least one wind converter to the electrical grid, wherein the rotation frame reference is generated by a phase lock loop based at least on the voltage at the POC.