System and method for controlling a power generation system based on PLL errors

• US 9,641,113 B2
• Filed: 02/28/2014
• Issued: 05/02/2017
• Est. Priority Date: 02/28/2014
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Larsen, Einar Vaughn, Ren, Wei, Barker, Sidney Allen
• Primary Examiner(s): Dole, Timothy J
• Assistant Examiner(s): Rivera-Perez, Carlos
• Application Number:
  US14/193,755
• Publication Number:
  US 20150249412A1
• Time in Patent Office: 1,159 Days
• Field of Search: 363 34, 363 35, 363 37- 47, 363 50- 58, 363 74, 363 79, 363 95- 99, 363131-134, 363 15- 2103, 323205-211, 323222-226, 323271-278, 323282-286, 323299, 323351, 323906, 323237, 323244, 323280, 323908, 327141-163, 327237, 327243, 327244, 307 85- 87, 361 18, 361 78, 361 79, 361 85, 361 86, 361 88-102, 290 44, 290 52, 290 55
• CPC Class Codes: F03D 7/0284 in relation to the state of the electric grid
• CPC Class Codes: F03D 7/048 controlling wind farms
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy wind motors F03D
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/44 with means for ensuring correct phase sequence
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: H02P 23/26 Power factor control [PFC]
• CPC Class Codes: H02P 9/007 Control circuits for doubly fed generators
• 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

In one aspect, a method for controlling a power generation system may generally include determining a phase angle error associated with the power generation system, determining a scaling factor based on the phase angle error, generating a current command for controlling the operation of a power convertor of the power generation system and applying the scaling factor to the current command such that the current command is reduced when the phase angle error exceeds a predetermined error threshold.

Claims

1. A method for controlling a power generation system, the method comprising:

determining, with a computing device, a phase angle error associated with tracking the power generation system based on measurement signals received from one or more voltage transducers;

determining, with the computing device, a scaling factor based on the phase angle error, the scaling factor corresponding to a value ranging from zero to one when the phase angle error exceeds the predetermined error threshold and a value of one for all phase angle errors below the predetermined error threshold;

generating, with the computing device, a current command for controlling the operation of a power convertor of the power generation system; and

applying, with the computing device, the scaling factor to the current command such that the current command is reduced when the phase angle error exceeds a predetermined error threshold.

2. The method of claim 1, wherein the scaling factor is defined as a function of a cosine of the phase angle error.

3. The method of claim 1, wherein the predetermined error threshold corresponds to an angle ranging from about 30 degrees to about 60 degrees.

4. The method of claim 1, wherein generating the current command comprises mnerating a real current command and a reactive current command for controlling the operation of the power convertor.

5. The method of claim 4, wherein applying the scaling factor to the current command comprises applying the scaling factor as a multiplier to the real current command and the reactive current command such that both current commands are reduced when the phase angle error exceeds the predetermined error threshold.

6. The method of claim 1, further comprising controlling the operation of the power convertor based on the scaled current command.

7. The method of claim 1, further comprising:

generating a proportional gain constant based on the scaling factor when the phase angle error exceeds the predetermined error threshold; and

utilizing the proportional gain constant within a phase-locked loop (PLL) regulator of the power generation system to generate a phase angle signal for synchronizing operation of the power generation system with an electrical grid.

8. The method of claim 1, wherein the power generation system comprises a wind turbine system.

9. A method for controlling a power generation system, the method comprising:

determining, with a computing device, a phase angle error associated with tracking the power generation system based on measurement signals received from one or more voltage transducers;

determining, with the computing device, a scaling factor based on the phase angle error;

generating, with the computing device, a proportional gain constant based on the scaling factor when the phase angle error exceeds a predetermined error threshold; and

inputting, with the computing device, the proportional gain constant into a phase-locked loop (PLL) regulator of the power generation system to generate an output from the PLL regulator corresponding to a phase angle signal for synchronizing operation of the power generation system with an electrical grid,

wherein the scaling factor decreases as the phase angle error is increased beyond the predetermined error threshold and the proportional gain constant is configured to increase with decreases in the scaling factor.

10. The method of claim 9, wherein the scaling factor is defined as a function of a cosine of the phase angle error.

11. The method of claim 9, wherein the predetermined error threshold corresponds to an angle ranging from about 30 degrees to about 60 degrees.

12. The method of claim 9, further comprising controlling the operation of a power convertor of the power generation system based on the phase angle signal.

13. The method of claim 9, further comprising:

generating a current command for controlling the operation of a power convertor of the power generation system; and

applying the scaling factor to the current command such that the current command is reduced when the phase angle error exceeds the predetermined error threshold.

14. The method of claim 9, wherein the power generation system comprises a wind turbine system.

15. A wind turbine system, comprising:

a generator;

a power convertor coupled to the generator; and

a controller configured to control the operation of the power convertor, the controller including instructions that, when implemented by one or more processors, configure the controller to;

determine a phase angle error associated with tracking the power generation system based on measurement signals received from one or more voltage transducers;

determine a scaling factor based on the phase angle error, the scaling factor corresponding to a value ranging from zero to one when the phase angle error exceeds the predetermined error threshold and a value of one for all phase angle errors below the predetermined error threshold;

generate a current command for controlling the operation of the power convertor; and

apply the scaling factor to the current command such that the current command is reduced when the phase angle error exceeds a predetermined error threshold.

16. The wind turbine system of claim 15, wherein the controller is further configured to generate a proportional gain constant based on the scaling factor when the phase angle error exceeds the predetermined error threshold and utilize the proportional gain constant within a phase-locked loop (PLL) regulator to generate a phase angle signal for synchronizing the operation of the power generation system with an electrical grid.

17. The wind turbine system of claim 15, wherein the generator corresponds to a doubly-fed induction generator.