Fuel-cell based power generating system having power conditioning apparatus

• US 7,808,129 B2
• Filed: 10/24/2006
• Issued: 10/05/2010
• Est. Priority Date: 10/24/2005
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Pradhan, Sanjaya K., Mazumder, Sudip K.
• Primary Examiner(s): Deberadinis; Robert L.
• Application Number:
  US12/084,021
• Publication Number:
  US 20090102291A1
• Time in Patent Office: 1,442 Days
• Field of Search: 307/58, 307/82, 307/140
• US Class Current: 307/140
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A power conditioner includes power converters for supplying power to a load, a set of selection switches corresponding to the power converters for selectively connecting the fuel-cell stack to the power converters, and another set of selection switches corresponding to the power converters for selectively connecting the battery to the power converters. The power conveners output combined power that substantially optimally meets a present demand of the load.

Claims

1. A power conditioner in power generating system including a fuel-cell stack and a battery, comprising:

a plurality of distributed power converters for supplying power to a load;

a plurality of first selection switches corresponding to said power converters for selectively connecting the fuel-cell stack to said power converters; and

a plurality of second selection switches corresponding to said power converters for selectively connecting the battery to said power converters;

wherein said power converters output combined power that substantially optimally meets a present demand of the load.

2. The power conditioner as defined in claim 1, wherein said power converters are connected in parallel for distribution of power from the fuel cell stack among the power converters.

3. The power conditioner as defined in claim 2, wherein said power converters comprise bidirectional dc-dc converters.

4. The power conditioner as defined in claim 1, further comprising:

a first controller for generating first switching signals for operating said power converters; and

a second controller for generating reference signals for enabling said first controller to generate said first switching signals, and second switching signals for operating said plurality of first and second selection switches.

5. The power conditioner as defined in claim 4, wherein said first controller comprises:

a first error compensator for generating a compensated signal for an error between a sensed current from said power converters and a corresponding reference signal from said second controller; and

a modulator for modulating said compensated signal to generate said first switching signals for operating said power converters.

6. The power conditioner as defined in claim 5, wherein said second controller comprises:

a second error compensator for generating a compensated signal for an error between optimal fuel utilization and an actual fuel utilization by the fuel-cell stack;

a third error compensator for generating a compensated signal for an error between a desired output voltage of said power converters and an actual output voltage of said power converter; and

a power sharing block for generating said reference signals for said first controller.

7. The power conditioner as defined in claim 6, wherein said optimal fuel utilization is output from a predefined performance map.

8. A power generating system, comprising

a fuel cell stack for generating power;

a battery source for generating alternate power;

a plurality of distributed power converters for supplying power to a load;

a plurality of first selection switches corresponding to said power converters for selectively connecting said fuel cell stack to said power converters; and

a plurality of second selection switches corresponding to said power converters for selectively connecting said battery to said power converters;

wherein said power converters output combined power that substantially optimally meets a present demand of the load.

9. The power generating system as defined in claim 8, further comprising a balance-of-plant system (BOPS) for providing fuel and oxygen to said fuel cell stack to enable said fuel cell stack to generate power.

10. The power generating system as defined in claim 8, wherein said power converters are connected in parallel for distribution of power from the fuel cell stack among the power converters.

11. The power generating system as defined in claim 10, wherein power converters comprise bidirectional dc-dc converters.

12. The power generating system as defined in claim 8, further comprising:

a first controller for generating first switching signals for operating said power converters; and

a second controller for generating reference signals for enabling said first controller to generate said first switching signals, and second switching signals for operating said plurality of first and second selection switches.

13. The power generating system as defined in claim 10, wherein said first controller comprises:

a first error compensator for generating a compensated signal for an error between a sensed current from said power converters and a corresponding reference signal from said second controller; and

a modulator for modulating said compensated signal to generate said first switching signals for operating said power converters.

14. The power generating system as defined in claim 13, wherein said second controller comprises:

a second error compensator for generating a compensated signal for an error between optimal fuel utilization and an actual fuel utilization by the fuel-cell stack;

a third error compensator for generating a compensated signal for an error between a desired output voltage of said power converters and an actual bus voltage of said power converters; and

a power sharing block for generating said reference signals for said first controller.

15. The power generating system as defined in claim 14, wherein said optimal fuel utilization is output from a predefined performance map.