Fuel cell system controller

• US 8,563,188 B2
• Filed: 03/07/2012
• Issued: 10/22/2013
• Est. Priority Date: 07/27/1999
• Status: Expired due to Fees

• Current Assignee: DCNS SA (Government of France)
• Original Assignee: IdaTech LLC (IdaTech Ltd.)
• Inventors: Edlund, David J., Herron, Thomas G., Holmes, Craig F.
• Primary Examiner(s): Alejandro, Raymond
• Application Number:
  US13/414,058
• Publication Number:
  US 20120231356A1
• Time in Patent Office: 594 Days
• Field of Search: 429/430, 429/431, 429/432, 429/492, 429/499, 429/501, 429/498
• US Class Current: 429/430
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04298 Processes for controlling fuel cells or fuel cell systems
• CPC Class Codes: H01M 8/04365 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/04552 of the individual fuel cell
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04582 of the individual fuel cell
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04619 of fuel cell stacks
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• CPC Class Codes: H01M 8/0656 by electrochemical means H01M8/065 takes precedence
• CPC Class Codes: H01M 8/0662 Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: H01M 8/0687 Reactant purification by the use of membranes or filters
• CPC Class Codes: H01M 8/249 comprising two or more groupings of fuel cells, e.g. modular assemblies
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell system that includes a control system for regulating the power produced by the fuel cell system. The fuel cell system includes a fuel cell stack adapted to produce electrical power from a feed. In some embodiments, the fuel cell system includes a fuel processing assembly adapted to produce the feed for the fuel cell stack from one or more feedstocks. The control system regulates the power produced by the fuel cell system to prevent damage to, and/or failure of, the system.

Claims

1. A fuel cell system configured to receive an applied load, the fuel cell system comprising:

a fuel cell stack configured to produce a stack electrical output from oxidant and a feed stream, wherein the stack electrical output has a stack current, wherein the fuel cell stack includes at least one proton exchange membrane fuel cell or alkaline fuel cell; and

a step-up converter, wherein the step-up converter is configured to receive the stack electrical output from the fuel cell stack and to produce a step-up converter electrical output therefrom, wherein the fuel cell system is configured to provide a portion of the step-up converter electrical output to the applied load, and further wherein the step-up converter is configured to selectively adjust the step-up converter electrical output to maintain the stack current below a threshold current value, wherein the fuel cell stack has a currently available electrical output, wherein the threshold current value is based, at least in part, on the currently available electrical output, wherein the fuel cell stack has a maximum rated electrical output, and further wherein the threshold current value is based, at least in part, on the maximum rated electrical output wherein the fuel cell system further includes a controller, wherein the controller is configured to selectively control the operation of the step-up converter by adjusting the step-up converter electrical output to maintain the stack current below the threshold current value.

2. The fuel cell system of claim 1, wherein the fuel cell system further includes a communication line that provides electrical communication between the controller and the step-up converter, and further wherein the controller is configured to generate a control signal and to provide the control signal to the step-up converter via the communication line to selectively control the operation of the step-up converter.

3. The fuel cell system of claim 1, wherein the fuel cell system further includes a sensor configured to detect the stack electrical output, and further wherein the controller is configured to selectively control the operation of the step-up converter based, at least in part, on the detected stack electrical output.

4. The fuel cell system of claim 3, wherein the controller is further configured to control a flow rate of the feed stream to the fuel cell stack based, at least in part, on the stack current.

5. The fuel cell system of claim 3, wherein the controller is configured to control a flow rate of the feed stream to the fuel cell stack to be proportional to the stack current.

6. The fuel cell system of claim 1, wherein the fuel cell system further includes a contactor configured to selectively disconnect the applied load from the fuel cell system, and further wherein the controller is configured to control the operation of the contactor.

7. The fuel cell system of claim 1, wherein the fuel cell system further includes a fuel processing assembly configured to generate the feed stream.

8. The fuel cell system of claim 7, wherein the fuel processing assembly is configured to produce a mixed gas stream that includes hydrogen gas from a feedstock stream, and further wherein the fuel processing assembly includes a separation region configured to separate the mixed gas stream into the feed stream and a byproduct stream.

9. The fuel cell system of claim 1, wherein the stack electrical output is a DC stack electrical output, and further wherein the step-up converter electrical output is a DC step-up converter electrical output.

10. The fuel cell system of claim 1, wherein the fuel cell system further includes an inverter configured to receive the step-up converter electrical output and to produce an AC output therefrom.

11. The fuel cell system of claim 1, wherein the fuel cell system further includes a battery bank configured to store a portion of the step-up converter electrical output.

12. The fuel cell system of claim 11, wherein the battery bank is configured to produce a battery bank electrical output, and further wherein the fuel cell system includes a sensor configured to detect the battery bank electrical output.

13. A method of operating the fuel cell system of claim 1, wherein the fuel cell system is configured to receive an applied load, the method comprising:

delivering the feed stream to the fuel cell stack;

receiving oxidant by the fuel cell stack;

producing the stack electrical output from at least a portion of the feed stream and at least a portion of the oxidant;

restricting, with the step-up converter, the stack electrical output from exceeding the maximum rated electrical output, wherein the restricting is responsive to the applied load exceeding the maximum rated electrical output; and

preventing, with the step-up converter, the stack electrical output from exceeding the currently available electrical output, wherein the preventing is responsive to the applied load exceeding the currently available electrical output.

14. The method of claim 13, wherein at least one of the restricting and the preventing includes controlling the step-up converter electrical output.

15. The method of claim 13, wherein the method further includes operating the fuel cell system under conditions in which the applied load exceeds the currently available electrical output while preventing, with the step-up converter, the stack electrical output from exceeding the currently available electrical output.

16. The method of claim 15, wherein the method further includes operating the fuel cell system under conditions in which the applied load exceeds the maximum rated electrical output, while restricting, with the step-up converter, the stack electrical output from exceeding the maximum rated electrical output.

17. A method of controlling the operation of the fuel cell system of claim 1, wherein the fuel cell system further includes a battery bank configured to receive a portion of the step-up converter electrical output, and further wherein the battery bank has a battery bank electrical output, the method comprising:

detecting the battery bank electrical output; and

controlling the step-up converter electrical output based, at least in part, on the battery bank electrical output.