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US5009967A
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Fuel cell power plant fuel control
Assignee: UTC Power Corp
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Filing: 1989-10-24
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Granted: 1991-04-23
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Expires: 2009-10-24
Abstract
Abstract Fuel cell current is sensed (30) and during a transient, a feed forward demand signal (50) sent to the fuel flow regulator (58). A nominal desired reformer temperature is established for the new fuel cell current. This desired temperature signal (62) is dynamically compensated (64) to establish the operating temperature set point (72). A predominantly lead compensation (66) is achieved for a desired temperature increase and a predominantly lag compensation (68) for a desired temperature decrease. Increased reliance on the temperature as a result of the system input reduces reliance on the accuracy of fuel flow measurement and on the consistency of fuel heating value.
Inventors
- 👤 Glenn W. Scheffler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:55
CPC Classifications
H; H01; H01M; H01M8/00; H01M8/04; H01M8/04298; H01M8/04313; H01M8/0432; H01M8/04365; H01M8/0438; H01M8/04425; H01M8/04537; H01M8/04574; H01M8/04589; H01M8/04694; H01M8/04746; H01M8/04776; H01M8/06; H01M8/0606; H01M8/0612; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
333 words
In a fuel cell power plant having, fuel supply means for supplying a flow of fuel, a reformer receiving and reforming said flow of fuel, a fuel stack receiving fuel from said reformer, a conduit for conveying fuel cell exhaust containing excess hydrogen to said reformer, a burner for burning said exhaust and said reformer in heat exchange relationship with the fuel supply passing through said reformer; a control system comprising: a current sensor for sensing the electrical load on said fuel cell stack and establishing a current sensed signal; a fuel flow summation point; means for conducting said current sensed signal to said fuel flow summation point as a nominal desired fuel flow signal; a temperature sensor for sensing the temperature of the reformed fuel at said reformer and establishing a temperature sensed signal; a first function generator for setting a nominal desired reformer fuel temperature set point representing the steady state desired temperature as a function of the sensed current; a dynamic compensator for modifying said desired reformer fuel temperature set point to obtain a transient temperature set point comprising, a first lead/lag compensator, a second lead/lag, compensator, one of said lead/lag compensators generating a predominantly lead characteristic signal and the other generating a predominantly lag characteristic signal, and a high select component for selecting and passing the higher signal of said lead characteristic signal and said lag characteristic signal; error means for comparing said higher signal with said sensed temperature signal and establishing a temperature error signal; means for modifying said nominal desired fuel flow signal as a function of by said temperature error signal and establishing a transient desired fuel flow set point signal to said fuel flow summation point; fuel flow sensing means for establishing a fuel flow sensed signal; means for conveying said fuel flow sensed signal to said fuel flow summation point and establishing a fuel flow error signal; and fuel flow control means responsive to said fuel flow error signal for controlling said fuel flow.
Claim 2
Dependent Claim
333 words
In a fuel cell power plant having, fuel supply means for supplying a flow of fuel, a reformer receiving and reforming said flow of fuel, a fuel stack receiving fuel from said reformer, a conduit for conveying fuel cell exhaust containing excess hydrogen to said reformer, a burner for burning said exhaust and said reformer in heat exchange relationship with the fuel supply passing through said reformer; a control system comprising: a current sensor for sensing the electrical load on said fuel cell stack and establishing a current sensed signal; a fuel flow summation point; means for conducting said current sensed signal to said fuel flow summation point as a nominal desired fuel flow signal; a temperature sensor for sensing the temperature of the reformed fuel at said reformer and establishing a temperature sensed signal; a first function generator for setting a nominal desired reformer fuel temperature set point representing the steady state desired temperature as a function of the sensed current; a dynamic compensator for modifying said desired reformer fuel temperature set point to obtain a transient temperature set point comprising, a first lead/lag compensator, a second lead/lag, compensator, one of said lead/lag compensators generating a predominantly lead characteristic signal and the other generating a predominantly lag characteristic signal, and a high select component for selecting and passing the higher signal of said lead characteristic signal and said lag characteristic signal; error means for comparing said higher signal with said sensed temperature signal and establishing a temperature error signal; means for modifying said nominal desired fuel flow signal as a function of by said temperature error signal and establishing a transient desired fuel flow set point signal to said fuel flow summation point; fuel flow sensing means for establishing a fuel flow sensed signal; means for conveying said fuel flow sensed signal to said fuel flow summation point and establishing a fuel flow error signal; and fuel flow control means responsive to said fuel flow error signal for controlling said fuel flow.
Claim 3
Dependent Claim
48 words
A control system as in claim 1: conversion means for providing a converted signal of unity for a temperature error of zero; and said means for modifying said nominal desired fuel flow signal comprising multiplication means for multiplying said nominal desired fuel flow signal by said converted signal.
Claim 4
Dependent Claim
28 words
A control system as in claim 2: said means for conducting said current sensed signal to said fuel flow summation point being free of proportional or integral action.
Claim 5
Dependent Claim
21 words
A control system as in claim 3: a signal conditioner for applying proportional and integral action to said temperature error signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-22 | 1994-10-22 | 1995-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-22 | 1998-10-22 | 1999-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-22 | 2002-10-22 | 2003-04-23 | $7700.00 | Window Closed / Lapsed |