Wind turbine power production using positive and negative sequence current component parameters generated based on operational mode

Patent metadata

Field	Value
Publication number	US-9382898-B2
Application number	US-201113884796-A
Country	US
Kind code	B2
Filing date	Nov 8, 2011
Priority date	Nov 10, 2010
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A wind turbine includes a grid side converter coupled to a grid via a power line. The method includes determining a first active power reference and a first reactive power reference indicating a requested amount of active power and reactive power, respectively, depending on at least a wind turbine operation strategy; determining a positive and negative sequence components of a grid voltage; determining indications of an actual amount of active power and reactive power to be supplied by the grid side converter to the grid, respectively; generating a parameters defining a proportion of positive sequence current component and negative sequence current component to be injected by the grid side converter in order to supply active power and reactive power; and supplying, with the grid side converter, active and reactive power to the power line based on the current reference.

First claim

What is claimed is:

1. A method for operating a wind turbine comprising a grid side converter, the grid side converter being coupled with an electrical grid, the method comprising:
determining, based on an operational mode for the wind turbine selected from a plurality of predetermined operational modes, a first active power reference indicating a requested amount of active power and a first reactive power reference indicating a requested amount of reactive power;
determining, based on the first active power reference, a second active power reference indicating an actual amount of active power to be supplied by the grid side converter to the electrical grid;
determining, based on the first reactive power reference, a second reactive power reference indicating an actual amount of reactive power to be supplied by the grid side converter to the electrical grid;
generating, based on the selected operational mode, first and second parameters, wherein the first parameter indicates a first proportion of positive sequence and negative sequence current components to supply the actual amount of active power, and wherein the second parameter indicates a second proportion of positive sequence and negative sequence current components to supply the actual amount of reactive power;
generating a first current reference based on at least the second active power reference, the second reactive power reference, positive sequence and negative sequence voltages determined from a measured grid voltage, and the first and second parameters; and
supplying, using the grid side converter, active and reactive power to the electrical grid based on the first current reference.

2. The method of claim 1 , further comprising:
determining, based on the selected operational mode, whether to adjust at least one of the requested amounts of active power and reactive power,
wherein determining the second active power reference and the second reactive power reference are further based on the determination of whether to adjust at least one of the requested amounts, and
wherein, when the determination indicates to not adjust the requested amounts, the determined second active power reference equals the first active power reference, and the determined second reactive power reference equals the first reactive power reference.

3. The method of claim 2 , wherein determining whether to adjust at least one of the requested amounts comprises:
determining whether a second current reference calculated using the first active power reference and the first reactive power reference would cause the grid side converter to exceed a predetermined current limit; and
adjusting, when the second current reference would cause the grid side converter to exceed the predetermined current limit, at least one of the requested amounts such that the first current reference does not cause the grid side converter to exceed the predetermined current limit.

4. The method of claim 2 , wherein determining whether to adjust at least one of the requested amount of active power and reactive power comprises:
determining whether to determine the second active power reference and the second reactive power reference further based on predetermined priority levels indicating whether regulating the active power or regulating the reactive power to corresponding power reference levels has higher priority.

5. The method of claim 3 , wherein determining whether the second current reference would cause the grid side converter to exceed the predetermined current limit comprises:
calculating, for each phase of a plurality of phases of power to be supplied to the electrical grid, a respective maximum current value for the second current reference, the calculation based on at least the selected operation mode, the first active power reference, the first reactive power reference, the positive sequence voltage, the negative sequence voltage, the first parameter, the second parameter, and a determined phase angle,
wherein the second current reference would cause the grid side converter to exceed the predetermined current limit when at least one of the maximum current values exceeds a predetermined phase current limit.

6. The method of claim 5 , wherein calculating the maximum current value for each phase comprises:
determining an active current ellipse defined by at least the first parameter, the positive sequence voltage, the negative sequence voltage, and the first active power reference,
determining a reactive current ellipse defined by at least the second parameter, the positive sequence voltage, the negative sequence voltage, a determined in-quadrature positive sequence voltage, a determined in-quadrature negative sequence voltage, and the first reactive power reference,
producing a combined current ellipse from the active current ellipse and the reactive current ellipse,
rotating the combined current ellipse about the determined phase angle, and
determining a plurality of maximum projections of the combined current ellipse onto the abc axes corresponding to a three-phase system, wherein each projection onto the abc axes corresponds to a maximum current value in the respective abc phases of the three-phase system.

7. The method of claim 5 , wherein the phase angle is substantially equal to half of a difference between the positive and negative sequence angles of the measured grid voltage.

8. The method of claim 1 , further comprising:
determining at least one of whether the second active power reference is within a predetermined active power range and whether the second reactive power reference is within a predetermined reactive power range, and
adjusting at least one of the second active power reference and the second reactive power reference such that the second active power reference is within the predetermined active power range and the second reactive power reference is within the predetermined reactive power range.

9. The method of claim 8 , further comprising at least one of:
replacing the second active power reference with:
an upper limit value of the predetermined active power range when the second active power reference exceeds the upper limit value, and
a lower limit value of the predetermined active power range when the second active power reference is less than the lower limit value, and

replacing the second reactive power reference with:
an upper limit value of the predetermined reactive power range when the second reactive power reference exceeds the upper limit value, and
a lower limit value of the predetermined reactive power range when the second reactive power reference is less than the lower limit value.

10. The method of claim 1 , wherein the second active power reference and the second reactive power reference are determined based on at least the selected operational mode, the first active power reference, the first reactive power reference, the first parameter, the second parameter, the positive sequence voltage, the negative sequence voltage, and a determined phase angle.

11. The method of claim 1 , wherein the operational mode is selected based on at least one of the following: a determined type of a grid fault, a determined location of the grid fault, a determined severity of the grid fault, a determined grid support requirement, a determined wind farm support requirement, a determined wind turbine performance factor, and a determined priority of active or reactive power injection.

12. The method of claim 11 , wherein the determined wind turbine performance factor corresponds to at least one of:
reducing a ripple in an output of a machine-side converter of the wind turbine, a DC link voltage, an output of the gr

Assignees

• Teodorescu Remus
• Rodriguez Pedro
• Alloza Alvaro Luna
• Gupta Amit Kumar
• Vestas Wind Sys As

Inventors

• Teodorescu Remus
• Rodriguez Pedro
• Alloza Alvaro Luna
• Gupta Amit Kumar

Classifications

• H02J3/38

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• F03D9/257

  the wind motor being part of a wind farm · CPC title

• H02J2101/28

  Wind energy · CPC title

• F03D9/255

  connected to electrical distribution networks; Arrangements therefor · CPC title

• Y02E40/50

  Arrangements for eliminating or reducing asymmetry in polyphase networks · CPC title