Secondary power source for use in a back-up power system

• US 6,787,259 B2
• Filed: 01/15/2003
• Issued: 09/07/2004
• Est. Priority Date: 09/12/2002
• Status: Expired due to Fees

• Current Assignee: Proton Energy Systems, Inc. (NEL ASA)
• Original Assignee: Metallic Power, Inc.
• Inventors: Erturk, Erol, Sundar, Rajagopalan, Colborn, Jeffrey A., Alstadt, Raymond H.
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US10/342,579
• Publication Number:
  US 20040053093A1
• Time in Patent Office: 601 Days
• Field of Search: 429/22, 429/23
• US Class Current: 429/430
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04604 Power, energy, capacity or load
• CPC Class Codes: H01M 8/0491 of fuel cell stacks
• CPC Class Codes: H01M 8/04925 Power, energy, capacity or load
• 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: H01M 8/18 Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A regulated DC power supply facilitates extended and uninterrupted power to a load by using a secondary power source such as a regenerative fuel cell that has its DC power output conditioned by a power converter. The DC power supply includes a rectifier that converts AC power from an AC power source to DC power for a load coupled to a DC bus. A fuel cell arrangement is electrically coupled to a power converter that is coupled in turn to the DC bus, the converter conditions an unconditioned DC power output of the fuel cell to the load. A system controller is communicatively coupled to the rectifier, the converter and to a fuel cell controller, the fuel cell controller initiating DC power output from the fuel cell arrangement upon detecting the AC power outage (or disengaging the fuel cell upon resumption of AC power).

Claims

1. A regulated DC power supply comprising:

a rectifier coupled between a primary AC power source and a DC bus, the rectifier adapted to convert AC power from the AC power source to DC power for a load;

a fuel cell arrangement electrically coupled to a power converter that is coupled to the DC bus, the converter adapted to condition an unconditioned DC power output of the fuel cell to the load; and

a fuel cell controller communicatively coupled with the fuel cell arrangement and adapted to initiate DC power output from the fuel cell arrangement upon detecting an AC power outage; and

disengage the fuel cell upon detecting AC power resumption.

2. The DC power supply of claim 1, further comprising a system controller communicatively coupled to the rectifier and to the fuel cell controller, wherein the system controller is adapted to engage the fuel cell arrangement via the fuel cell controller upon detecting an AC power outage and disengage the fuel cell arrangement upon detecting AC power resumption.

3. The DC power supply of claim 1, further comprising a plurality of rectifiers coupled between the AC power source and the DC bus.

4. The DC power supply of claim 3, further comprising a plurality of power converters coupled between the fuel arrangement and the DC bus.

5. The DC supply of claim 3, further comprising a chassis adapted to support the rectifiers in an N+1 redundancy arrangement.

6. The DC supply of claim 5, wherein the chassis is adapted to support a backplane having an AC bus, a conditioned DC bus and the unconditioned DC bus mounted thereon.

7. The DC power supply of claim 1, further comprising a plurality of power converters coupled between the fuel arrangement and the DC bus.

8. The DC power supply of claim 1, further comprising a battery arrangement electrically coupled to the DC bus and adapted to provide uninterrupted DC power to the load when the power level drops below a predetermined level.

9. The DC power supply of claim 8, further comprising a current share device coupled to the DC and adapted to control the output current of the battery and the fuel cell.

10. In DC power supply of claim 1, further comprising an auxiliary DC power has adapted to provide power to the fuel cell controller and the fuel cell components.

11. The DC power supply of claim 1, wherein the fuel cell controller is adapted to control the load so as to conduct load-shedding to reduce the current driven on the fuel cell.

12. A regulated DC power supply comprising:

a plurality of rectifiers coupled between a primary AC power source and a DC bus, the rectifiers adapted to convert AC power from the AC power source to DC power for a load;

a regenerative fuel cell (RFC) arrangement electrically coupled to a plurality of power converters that are coupled in parallel with the DC bus, the converters adapted to condition a DC power output of the RFC arrangement to the load; and

a fuel cell controller communicatively coupled with the fuel cell arrangement and adapted to initiate DC power output from the fuel cell arrangement upon detecting an AC power outage.

13. The DC power supply of claim 12, further comprising a system controller communicatively coupled to the rectifiers.

14. The DC power supply of claim 13, wherein the system controller is coupled to the RFC controller and adapted to request power from the RFC via the fuel cell controller upon detecting an AC power outage.

15. The DC supply of claim 12, wherein the RFC is recharged by drawing power from the DC bus supplied by the rectifiers from the AC source.

16. The DC supply of claim 12, wherein the RFC is recharged without drawing power from the DC bus.

17. The DC supply of claim 12, further comprising a chassis adapted to support the rectifiers in an N+1 redundancy arrangement.

18. The DC supply of claim 17, wherein the chassis is adapted to support a backplane that includes an AC bus and the DC bus mounted thereon.

19. The DC supply of claim 17, further comprising a battery arrangement electrically coupled to the DC bus and adapted to provide uninterrupted DC power to the load when the power level drops below a predetermined level.

20. The DC supply of claim 12, wherein the battery arrangement is recharged by drawing power from the DC bus supplied by the rectifiers from the AC source.

21. A method of providing extended backup power to a load via a power plant having a battery arrangement, the method comprising:

providing DC power to the load from the battery arrangement via a DC bus upon interruption of a primary power source;

shedding a portion of the load when the DC bus voltage reaches a predetermined transition voltage;

providing power to the DC bus at or below a predetermined DC bus voltage from a secondary power source;

using a secondary power source controller to share current between the battery arrangement and the secondary power source; and

upon detecting primary power source resumption, switching the load from the secondary power source and battery arrangement to the primary power source via the secondary power source controller.

22. The method of claim 21, further comprising the step of recharging the fuel cell arrangement and the battery arrangement after the fuel cell controller has switched the load to the primary power source.

23. A DC power plant configured to provide extended backup power to a load, the power plant including a battery arrangement adapted to temporarily provide power to the load upon interruption of a primary power source, the power plant comprising:

a secondary power source adapted to provide extended backup power to the load via a DC bus; and

a secondary power source controller adapted to shed a portion of the load when the battery voltage reaches a predetermined transition voltage and to thereafter initiate power production from the secondary power source, wherein the controller is also adapted to share current between the battery arrangement and the secondary power source.

24. The DC power plant of claim 23, wherein the secondary power source controller is also adapted to switch the load from the secondary power source and battery arrangement to the primary power source after primary power source resumption.

25. The DC power plant of claim 23, wherein the secondary power source is a fuel cell.

26. The DC power plant of claim 25, wherein the fuel cell is a regenerative fuel cell.