Startup power control in a fuel cell system

• US 8,263,276 B1
• Filed: 07/02/2009
• Issued: 09/11/2012
• Est. Priority Date: 07/08/2008
• Status: Active Grant

• Current Assignee: Bloom Energy Corporation
• Original Assignee: Bloom Energy Corporation
• Inventors: Gurunathan, Ranganathan, Srinivasan, Ramesh, Sarathy, Srinivasan Vijay
• Primary Examiner(s): DRODGE, JOSEPH W
• Application Number:
  US12/458,173
• Time in Patent Office: 1,167 Days
• Field of Search: 307/10.1, 307/10.6, 307/11, 307/18, 307/19, 307/21, 307/25, 307/64, 307/23, 307/24, 307/66, 307/149, 307/150, 429429-432, 429/50, 429/90, 700/286
• US Class Current: 429/429
• CPC Class Codes: H01M 2250/402 Combination of fuel cell with other electric generators combination of fuel cells with other electrochemical generator H01M16/003
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
• CPC Class Codes: Y02P 90/40 Fuel cell technologies in production processes

Abstract

A method for starting up a fuel cell arrangement includes receiving a first electrical signal from an alternative power source. At least a portion of the first electrical signal is provided to a balance of plant (BOP) load, where the BOP load is in electrical communication with a fuel cell system. It is determined whether a startup threshold of the fuel cell system is met. If the startup threshold is met, a second electrical signal is provided from the fuel cell system to the BOP load, where a combination of the first electrical signal and the second electrical signal corresponds to a load demand of the BOP load. A value of the second electrical signal is increased and a value of the first electrical signal is decreased until the load demand of the BOP load is met by the fuel cell system.

Claims

1. A method for starting up a fuel cell arrangement, the method comprising:

receiving a first electrical signal from an alternative power source;

providing at least a portion of the first electrical signal to a balance of plant (BOP) load, wherein the BOP load is in electrical communication with a fuel cell system;

determining whether a startup threshold of the fuel cell system is met;

if the startup threshold is met, providing a second electrical signal from the fuel cell system to the BOP load, wherein a combination of the first electrical signal and the second electrical signal corresponds to a load demand of the BOP load; and

increasing a value of the second electrical signal and reducing a value of the first electrical signal until the load demand of the BOP load is met by the fuel cell system.

2. The method of claim 1, wherein the first electrical signal is an alternating current (AC) signal, and further comprising converting the AC signal into a direct current (DC) signal using a rectifier.

3. The method of claim 2, wherein the rectifier comprises a diode rectifier.

4. The method of claim 1, further comprising providing the second signal to a BOP bus in electrical communication with the BOP load from a split bus in electrical communication with the fuel cell system.

5. The method of claim 4, further comprising preventing provision of the first electrical signal from the BOP bus to the split bus.

6. The method of claim 5, wherein provision of the first electrical signal from the BOP bus to the split bus is prevented using one or more diodes.

7. The method of claim 1, wherein the alternative power source comprises one or more of an electrical grid, a solar cell system, a wind turbine system, a hydroelectric system, a generator, and a battery.

8. The method of claim 1, wherein the startup threshold is based at least in part on a voltage of the second electrical signal, a current of the second electrical signal, or a power of the second electrical signal.

9. The method of claim 1, wherein the balance of plant (BOP) load comprises at least one of a control unit of the fuel cell system, a monitoring device of the fuel cell system or a balance of plant device of the fuel cell system.

10. The method of claim 9, wherein the balance of plant (BOP) load comprises a balance of plant blower device of the fuel cell system.

11. An apparatus comprising:

a fuel cell system;

a rectifier configured to

receive a first electrical signal from an alternative power source, wherein the first electrical signal is an alternating current (AC) signal;

convert the first electrical signal into a direct current (DC) signal; and

provide the DC signal to a balance of plant (BOP) load, wherein the BOP load is in electrical communication with the fuel cell system; and

a controller configured to

determine whether a startup threshold of the fuel cell system is met;

if the startup threshold is met, provide a second electrical signal from the fuel cell system to the BOP load, wherein a combination of the DC signal and the second electrical signal corresponds to a load demand of the BOP load; and

increase a value of the second electrical signal and reduce a value of the first electrical signal until the load demand of the BOP load is met by the fuel cell system.

12. The apparatus of claim 11, further comprising an inverter configured to:

receive a third electrical signal from the fuel cell system, wherein the third electrical signal is a DC signal;

convert the third electrical signal into a second AC signal; and

provide the second AC signal to an external load.

13. The apparatus of claim 12, wherein the external load comprises an electrical grid.

14. The apparatus of claim 13, wherein the alternative power source comprises the electrical grid.

15. The apparatus of claim 11, further comprising:

a split bus having a first positive bus, a first negative bus, and a first neutral bus, wherein the split bus is in electrical communication with the fuel cell system; and

a BOP bus having a second positive bus, a second negative bus, and a second neutral bus, wherein the BOP bus is in electrical communication with the BOP load.

16. The apparatus of claim 15, further comprising at least one diode in electrical communication with the split bus and the BOP bus, wherein the diode is configured to prevent provision of at least a portion of the first electrical signal from the BOP bus to the split bus.

17. The apparatus of claim 11, further comprising a DC/DC converter configured to increase a voltage of the second electrical signal.

18. A system for starting up a fuel cell arrangement, the system comprising:

means for receiving a first electrical signal from an alternative power source and for providing at least a portion of the first electrical signal to a balance of plant (BOP) load, wherein the BOP load is in electrical communication with a fuel cell system;

means for providing a second electrical signal from the fuel cell system to the BOP load if a startup threshold of the fuel cell system is met, wherein a combination of the first electrical signal and the second electrical signal corresponds to a load demand of the BOP load; and

means for increasing a value of the second electrical signal and for reducing a value of the first electrical signal until the load demand of the BOP load is met by the fuel cell system.

19. The system of claim 18, further comprising means for converting the first electrical signal from an alternating current (AC) signal to a direct current (DC) signal.

20. The system of claim 18, further comprising:

means for receiving a third electrical signal from the fuel cell system; and

means for providing the third electrical signal to an external load.

21. The system of claim 20, wherein the external load comprises an electrical grid, and further wherein the alternative power source comprises the electrical grid.

22. The system of claim 20, wherein the means for receiving the first electrical signal and for providing at least the portion of the first electrical signal to the BOP load comprises a rectifier, wherein the means for providing the second electric signal to the BOP load comprises a split bus, wherein the means for increasing the value of the second electrical signal and for reducing the value of the first electrical signal comprises a controller, wherein the means for receiving the third electrical signal comprises a direct current/direct current converter, and further wherein the means for providing the third electrical signal to the external load comprises an inverter.

23. The system of claim 20, wherein the means for increasing the value of the second electrical signal and for reducing the value of the first electrical signal further comprises means for determining whether the startup threshold is met by the fuel cell system.

24. The system of claim 18, wherein the alternative power source comprises one or more of a solar cell system, a wind turbine system, a hydroelectric system, a generator, and a battery.