Power control system for a fuel cell powered vehicle

• US 5,771,476 A
• Filed: 12/29/1995
• Issued: 06/23/1998
• Est. Priority Date: 12/29/1995
• Status: Expired due to Term

• Current Assignee: NuCellSys GmbH (Mercedes-Benz Group AG)
• Original Assignee: DBB Fuel Cell Engines GmbH
• Inventors: Strasky, Douglas G., Mufford, W. Edward
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/581,312
• Time in Patent Office: 907 Days
• Field of Search: 701/1, 701/22, 180/65.1, 180/65.2, 180/65.3, 180/65.4, 180/65.5, 307/10.1, 429/9, 429/19, 429/21, 429/30
• US Class Current: 701/22
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: B60L 58/33 by cooling
• CPC Class Codes: B60L 58/34 by heating
• CPC Class Codes: H01M 2250/20 Fuel cells in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04395 of cathode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: H01M 8/2495 of fuel cells of different types
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A power control system for controlling the supply of a reactant gas, such as air, for reaction within a fuel cell stack used to power, for example, a motor vehicle is set forth. The disclosed system may be used to reduce or eliminate compressor revving and instabilities common to prior systems in which fuel cell power output is dependent upon a flow of a reactant gas through a fuel cell stack, the flow of reactant gas being determined by the compressor speed.

Claims

1. In a fuel cell system for a motor vehicle having electric powered systems, said fuel cell system having a compressor for supplying a gas for reaction within a fuel cell stack, said fuel cell system further comprising a control system that includes a feedback signal path that provides a signal for use in controlling compressor speed based on at least one sensed fuel cell output power signal component, the control system further comprising:

(a) power summing means for determining the total amount of power demanded by said electric powered systems of said motor vehicle based on a plurality of sensed power demand signals and generating an output signal indicative of the compressor speed needed to meet the demanded power needs; and

(b) combining means for combining said signal output of said feedback signal path with said output of said power summing means to generate a compressor speed signal for control of said compressor.

2. In a fuel cell system for a motor vehicle having electric powered systems, said fuel cell system having a compressor for supplying a gas for reaction within a fuel cell stack, a control system comprising:

(a) power monitoring means for monitoring at least one signal component indicative of fuel cell power drawn by said electric powered systems of said motor vehicle;

(b) gas flow calculating means for calculating a required gas flow to said fuel cell stack to provide power to said electric powered systems as measured by said power monitoring means;

(c) gas flow monitoring means for monitoring gas flow to said fuel cell stack and comparing said monitored gas flow with said required gas flow to generate an error signal;

(d) feed forward monitoring means for determining power demand status of said electric powered systems of said motor vehicle based on plurality of demand signals;

(e) feed forward calculating means for calculating total power demanded by said motor vehicle based on correlating said demand signals monitored by said feed forward monitoring means with predetermined data for each of said electric powered systems, said predetermined data corresponding to power drawn by each of said electric powered systems in the state of said demand signals monitored by said feed forward monitoring means, said feed forward calculating means providing an output signal indicative of a calculated required gas flow to said fuel cell stack;

(f) combining means for combining said error signal with said output signal of said feed forward calculating means to generate a gas flow signal for control of said compressor.

3. In a fuel cell powered vehicle wherein fuel cell stack power output is dependent upon a flow of a reactant gas through a fuel cell stack, said flow of reactant gas being determined by compressor speed, a system comprising:

(a) means responsive to a measured fuel cell stack current value for providing a reactant gas mass flow signal output signal indicative of a reactant gas mass flow level required to maintain power output by said fuel cell stack at said measured fuel cell stack current value;

(b) feedback means for measuring actual reactant gas mass flow through said fuel cell stack and comparing said actual reactant gas mass flow to said reactant gas mass flow signal output to generate a correction signal;

(c) feed forward means for measuring power demands by said fuel cell powered vehicle based on status indicative of power demanded by a plurality of power consuming systems of said vehicle and generating a calculated reactant gas mass flow signal based on said measured power demands; and

(d) combining means for combining said correction signal with said calculated reactant gas mass flow signal to generate a control signal for controlling said speed of said compressor.

4. A control system for controlling the speed of a compressor to control mass flow of a reactant gas through a fuel cell stack of a fuel cell powered vehicle having electric power consuming systems, said control system comprising:

(a) first summing means for summing measured traction power and measured demand for auxiliary load power to generate a net power demand signal;

(b) first reactant gas mass flow determining means for generating a first reactant gas mass flow signal in response to said net power demand signal;

(c) fuel cell current measuring means for measuring fuel cell stack current through said fuel cell;

(d) second reactant gas mass flow determining means for generating a second reactant gas mass flow signal in response to said measured fuel cell stack current;

(e) actual reactant gas mass flow measuring means for measuring an actual reactant gas mass flow;

(f) comparing means for comparing said actual reactant gas mass flow to said second reactant gas flow signal to generate an error signal;

(g) PID signal generating means for generating a proportional-integral-derivative signal from said error signal means; and

(h) second summing means for summing said proportional-integral-derivative signal with said first reactant gas mass flow signal to generate a compressor speed signal for controlling said speed of said compressor.