Variable fuel cell power system for generating electrical power

• US 7,261,962 B1
• Filed: 09/19/2002
• Issued: 08/28/2007
• Est. Priority Date: 04/03/2000
• Status: Expired due to Term

• Current Assignee: Convergence Incorporated (Amazon.com, Inc.)
• Original Assignee: Convergence Incorporated (Amazon.com, Inc.)
• Inventors: Czajkowski, Kathleen A., Rebain, Stephen R.
• Primary Examiner(s): Alejandro; Raymond
• Assistant Examiner(s): Martin; Angela J.
• Application Number:
  US10/247,067
• Time in Patent Office: 1,804 Days
• Field of Search: 429/23, 429/22, 429/12, 429/13, 702/22, 702/60, 702/65
• US Class Current: 429/423
• 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 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: H02J 1/001 Hot plugging or unplugging of load or power modules to or from power distribution networks
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• 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: 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 60/50 Fuel cells

Abstract

The present invention provides an apparatus and methods for variably supplying power from a stand-alone fuel cell power supply system including a power conversion unit, a power switching unit and a load control unit. Preferably, a controller manages system configuration to switch the loads, the power conversion and the delivery between the two without reducing capacity by redundantly backing up each individual portion with a bank of at least two modules for each unit. Preferably, controller actuated devices are triggered automatically in response to monitors that sense performance operating parameters and detect values operating outside a threshold range. Preferably, each of the units and the components in each unit are banked in a plurality of modular units so that individual converters may be interchanged, individual fuel cells may be interchanged, individual controllers may be interchanged, and individual storage units such as batteries may be interchanged to ensure proper operation of each bank despite changes or failures in individual components of the bank. The power system may include couplers for connecting the system to dedicated outlets such as an NEC standard 120/240 volt building circuitry. The invention monitors multiple elements from fuel supply, fuel cells, converters, storage units, and controls as well as the loads for balanced, reliably robust, high power quality, and independent power supply.

Claims

1. A variable fuel cell power supply system comprising:

at least one power conversion unit comprising at least one fuel cell stack fed by at least one reformate source, and at least one energy storage device;

at least one load bus;

a switch bank including at least one switch, each switch selectively connecting at least one power conversion unit to said at least one load bus;

at least one load coupler, each load coupler selectively connecting a load line to said at least one load bus; and

at least one process control responsive to at least one operating parameter from said at least one load coupler to enhance operation of at least one of said reformate source, said at least one fuel cell stack and said at least one energy storage device to deliver a transient load energy demand, and maintaining an enhanced operation when a load energy demand is reduced below said transient load energy demand to replenish said energy storage devices.

2. The variable fuel cell power supply system as described in claim 1 wherein said energy storage device comprises at least one battery and at least one ultracapacitor connected in parallel, and said ultracapacitor is derated to operate at a partial charge when said battery is fully charged, thereby protecting said battery from deterioration due to supplying said transient load energy demand, and enabling said energy storage device to protect said fuel cell stack and said reformate source from deterioration due to supplying said transient load energy demand.