Method to control maximum current for a fuel cell
AssigneeIntelligent Energy Limited
InventorJeremy Bowman
Life of this patent
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Abstract
The disclosure relates to a fuel cell stack and corresponding method of operating the fuel cell stack. The method comprises: determining a maximum allowable current that may be drawn from the fuel cell stack; repeatedly determining a magnitude of change to the prevailing maximum allowable current based on a prevailing allowable current ramp rate and an actual measured current of the fuel cell stack; updating the maximum allowable current according to the periodically determined magnitude of change; and controlling operating parameters of the fuel cell stack according to the prevailing maximum allowable current.
Claims11
A method of operating a fuel cell system comprising:
- repeatedly determining a maximum allowable current that may be drawn from the fuel cell system based on at least one of a prevailing allowable current ramp rate, an actual measured current of the fuel cell system, and a parasitic current load of the fuel cell system;
- and
- controlling a plurality of operating parameters of the fuel cell system according to a most recent determination of the maximum allowable current as a function of one or more of:
- (i) a total system running time;
- (ii) a count of the total number of full stop-start cycles to which the fuel cell system has been subjected;
- (iii) an ambient humidity falling below a predetermined low humidity threshold;
- (iv) an ambient temperature falling below a predetermined low temperature threshold;
- (v) an ambient temperature rising above a predetermined high temperature threshold;
- (vi) a system voltage;
- (vii) the proximity of one or more cell voltages to a minimum cell voltage threshold and/or the proximity of a system temperature to a maximum temperature limit and,
- (viii) the maximum allowable current does not fall below a predetermined minimum current limit.
Dependencies are inferred from the claim text.