System and method for controlling uninterruptible power supply of electrical power systems

Patent metadata

Field	Value
Publication number	US-10998760-B2
Application number	US-201816144409-A
Country	US
Kind code	B2
Filing date	Sep 27, 2018
Priority date	Sep 27, 2018
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

Systems and methods of controlling uninterruptible power supplies of electrical power systems are described. According to one aspect, an electrical power system can include a generator having a stator and a rotor, a power converter coupled to a rotor bus of the rotor, and a control system comprising one or more control devices, the one or more control devices configured to operate the power converter to provide an AC signal for a rotor bus. The system can also include an uninterruptible power supply (UPS). The UPS can include a power storage element configured to receive and store electrical power, and configured to power the control system during a power failure, and, a health check circuit configured to verify a health status of the power storage element, and including a health check disable component configured to disable the health check circuit during the power failure.

First claim

What is claimed is:

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 and a rotor-side converter, the rotor-side converter coupled to the rotor via a rotor-side bus, the line-side converter coupled to a line-side bus;
a power supply electrically coupled in parallel to the line-side bus; and
a control system communicatively coupled to the electrical power system, the control system comprising one or more control devices, the one or more control devices configured to operate the electrical power system such that the rotor-side bus provides an AC signal for the power converter; and,
an uninterruptible power supply comprising:
a power storage element electrically coupled in parallel to the line-side bus, the power storage element also electrically coupled to the power supply, the power storage element configured to receive electrical power from the power supply, store the electrical power, and power the control system using the stored electrical power during a power failure; and,
a health check circuit configured to verify a health status of the power storage element, the health check circuit comprising a health check disable component configured to disable the health check circuit during the power failure.

2. The electrical power system of claim 1 , wherein the uninterruptible power supply further comprises a power failure sensor configured to sense a power failure condition on at least one phase of the rotor-side bus.

3. The electrical power system of claim 2 , wherein the control system is configured to direct the uninterruptible power supply to power the control system during the power failure.

4. The electrical power system of claim 1 , wherein the power storage element comprises at least one ultracapacitor.

5. The electrical power system of claim 4 , wherein the at least one ultracapacitor comprises a storage capacity of at least 300 Farads.

6. The electrical power system of claim 1 , wherein the power storage element comprises:
a bank of ultracapacitors coupled in series; and,
a plurality of balancing resistors coupled to the bank of ultracapacitors, wherein the plurality of balancing resistors are configured to distribute voltage imbalance across the bank of ultracapacitors.

7. The electrical power system of claim 6 , wherein each balancing resistor of the plurality of balancing resistors is coupled across an individual ultracapacitor of the bank of ultracapacitors.

8. The electrical power system of claim 1 , wherein the control system is further configured to monitor the uninterruptible power supply via a voltage divider circuit coupled to the power storage element.

9. A method of operating an uninterruptible power supply for a doubly fed induction generator system, the method comprising:
electrically coupling a power converter having a line-side converter and a rotor-side converter to a generator of the doubly fed induction generator system, the rotor-side converter coupled to a rotor of the generator via a rotor-side bus, the line-side converter coupled to a line-side bus;
electrically coupling a power supply in parallel to the line-side bus;
electrically coupling a power storage element in parallel to the line-side bus and electrically coupling the power storage element to the power supply;
converting an AC power at the line-side converter to a DC power for a DC link of the power converter;
storing power in the uninterruptible power supply;
performing a health check on a rate of decay of the power storage element in the uninterruptible power supply with health check circuitry;
sensing a first condition in the AC power; and
disabling the health check in response to sensing the first condition.

10. The method of claim 9 , further comprising disabling the health check circuitry in response to sensing the first condition.

11. The method of claim 9 , wherein performing the health check on the rate of decay comprises:
coupling the power storage element to a resistance of known value; and
measuring the rate of decay over time.

12. The method of claim 11 , wherein performing the health check on the rate of decay further comprises comparing the measured rate of decay against a set of tolerance decay bands.

13. A wind turbine 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 and a rotor-side converter, the line-side converter coupled to the power grid via a line-side bus, the rotor-side converter coupled to a rotor-side bus of the rotor and the line-side converter via a DC link;
a power supply electrically coupled in parallel to the line-side bus; and
a control system communicatively coupled to the electrical power system, the control system comprising one or more control devices, the one or more control devices configured to operate the electrical power system such that the rotor-side bus provides an AC signal for the power converter; and,
an uninterruptible power supply comprising:
a power storage element electrically coupled in parallel to the line-side bus, the power storage element also electrically coupled to the power supply, the power storage element configured to receive electrical power from the power supply, store the electrical power, and power the control system using the stored electrical power during a power failure; and,
a health check circuit configured to verify a health status of the power storage element, and comprising a health check disable component configured to disable the health check circuit during the power failure.

14. The wind turbine system of claim 13 , wherein the uninterruptible power supply further comprises a power failure sensor configured to sense a power failure condition on at least one phase of the rotor-side bus.

15. The wind turbine system of claim 14 , wherein the power failure sensor is configured to direct the uninterruptible power supply to power the control system during the power failure.

16. The wind turbine system of claim 13 , wherein the power storage element comprises at least one ultracapacitor.

17. The wind turbine system of claim 16 , wherein the at least one ultracapacitor comprises a storage capacity of at least 300 Farads.

18. The wind turbine system of claim 13 , wherein the power storage element comprises:
a bank of ultracapacitors coupled in series; and,
a plurality of balancing resistors coupled to the bank of ultracapacitors, wherein the plurality of balancing resistors are configured to distribute voltage imbalance across the bank of ultracapacitors.

19. The wind turbine system of claim 18 , wherein each balancing resistor of the plurality of balancing resistors is coupled across an individual ultracapacitor of the bank of ultracapacitors.

20. The wind turbine system of claim 13 , wherein the control system is further configured to monitor the uninterruptible power supply via a voltage divider circuit coupled to the power storage element.

Assignees

• Gen Electric

Inventors

• Trzemzalski Joseph Andrew

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02J11/00 Primary

  Circuit arrangements for providing service supply to auxiliaries of stations in which electric power is generated, distributed or converted · CPC title

• H02J9/062 Primary

  for AC powered loads · CPC title

• H02J3/381

  Dispersed generators · CPC title

• H02J2101/10

  Dispersed power generation using fossil fuels, e.g. diesel generators · CPC title