DFIG Converter with Active Filter

• US 20190312502A1
• Filed: 04/04/2018
• Published: 10/10/2019
• Est. Priority Date: 04/04/2018
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Ganireddy, Govardhan, Schnetzka, Harold Robert, Wagoner, Robert Gregory, Ridenour, Amy Marlene, Jha, Kapil, Kolhatkar, Yashomani Y., Tiwari, Arvind Kumar
• Granted Patent: US 10,778,112 B2
• Time in Patent Office: Days
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F05B 2220/706 an electrical generator
• CPC Class Codes: H02K 7/1838 Generators mounted in a nacelle or similar structure of a horizontal axis wind turbine
• CPC Class Codes: H02M 1/0054 Transistor switching losses periodically suspending operation of switching converter in low power mode H02M1/0035
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 1/126 using passive filters
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: H02M 7/2195 the switches being synchronously commutated at the same frequency of the AC input voltage
• CPC Class Codes: H02M 7/23 arranged for operation in parallel H02M7/2176 takes precedence
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• 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: 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

Abstract

Systems and methods for operating a power system having a doubly fed induction generator are provided. In example implementations, an electrical power system connected to a power grid can include a generator comprising a stator and a rotor, the stator connected to the power grid via a stator power path, and a power converter. The power converter can include a line-side converter coupled to the power grid via a converter power path and a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link, the rotor-side converter configured to convert a DC power on the DC link to an AC signal for the rotor bus. The power system can also include an active filter comprising one or more active controlled components, the active filter being coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

Claims

1. An electrical power system connected to a power grid, comprising:

a generator comprising a stator and a rotor, the stator connected to the power grid via a stator power path;

a power converter comprising;

a line-side converter coupled to the power grid via a converter power path; and

,

a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link, the rotor-side converter configured to convert a DC power on the DC link to an AC signal for the rotor bus; and

,

an active filter comprising one or more active-controlled components, the active filter being coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

2. The electrical power system of claim 1, further comprising a control system comprising one or more control devices, the one or more control devices configured to operate the rotor-side converter to provide the AC signal for the rotor bus.

3. The electrical power system of claim 2, wherein the rotor-side converter comprises one or more switching elements, wherein the one or more control devices operate the one or more switching elements in an overmodulation regime.

4. The electrical power system of claim 1, wherein the active-controlled components comprise one or more switching elements.

5. The electrical power system of claim 1, further comprising a passive filter coupled to the converter power path to further reduce harmonics of the electrical power system.

6. The electrical power system of claim 3, wherein the active filter is further configured to reduce harmonics caused by operating the one or more switching elements of the rotor-side converter in the overmodulation regime.

7. The electrical power system of claim 6, wherein the active filter is also coupled to the DC Link.

8. The electrical power system of claim 1, wherein the active filter is configured to receive at least one electrical condition from at least one of the rotor bus, the line-side converter, the rotor-side converter, a stator bus, a grid interconnection bus, and the DC link.

9. The electrical power system of claim 8, wherein the at least one electrical condition is one or more of current and voltage.

10. The electrical power system of claim 1, further comprising a series connection of an inductor and a capacitor coupled between the active filter and the rotor bus.

11. The electrical power system of claim 1, further comprising at least one inductor coupled between the active filter and the rotor bus.

12. The electrical power system of claim 1, wherein the active filter is coupled directly to terminals of the rotor-side converter.

13. A wind turbine system, comprising:

a generator comprising a stator and a rotor, the stator connected to the power grid via a stator power path;

a power converter comprising;

a line-side converter coupled to the power grid via a converter power path; and

,

a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link, the rotor-side converter configured to convert a DC power on the DC link to an AC signal for the rotor bus; and

,

an active filter comprising one or more active-controlled electronic components, the active filter being coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

14. The wind turbine system of claim 13, further comprising a control system comprising one or more control devices, the one or more control devices configured to operate the rotor-side converter to provide the AC signal for the rotor bus.

15. A method of operating an electrical power converter for a doubly fed induction generator system, the method comprising:

converting an AC power at a line-side converter to a DC power for a DC link;

receiving at a rotor-side converter the DC power from the DC link;

operating, using one or more control devices, the rotor-side converter to convert the DC power to an AC signal; and

operating an active filter coupled in parallel to the rotor-side converter to reduce at least one harmonic in the power system.

16. The method of claim 15, wherein operating, using the one or more control devices, the rotor-side converter to convert the DC power to the AC signal comprises operating one or more switching elements in an overmodulation regime.

17. The method of claim 16, wherein the active filter comprises one or more active-controlled components.

18. The method of claim 15, further comprising using a passive filter to reduce at least one harmonic caused by operating the rotor-side converter.

19. The method of claim 15, wherein providing output from the active filter reduces at least one harmonic caused by operating the rotor-side converter in an overmodulation regime.

20. The method of claim 15, wherein the doubly fed induction generator system is a wind driven doubly fed induction generator system configured to generate electrical power for a power grid.