Control strategy to prevent humidity cycling in a fuel cell
First Claim
Patent Images
1. A fuel cell system comprising:
- a fuel cell stack;
a power source; and
a controller, responsive to a power request signal, said controller including a damping filter that damps the power request signal over a damping time during a low power transient and provides a damped power demand signal to the fuel cell stack that provides more power than the power request signal during the damping time; and
wherein the controller is further responsive to a power source state of charge signal, said controller including a state of charge weighting factor look-up table that provides a state of charge multiplier factor depending on the power source state of charge, said controller multiplying the weighting factor by the damped power demand signal to increase or decrease the damped power demand signal depending on the state of charge of the power source, wherein excess power generated by the fuel cell stack above the power request signal is used to charge the power source.
13 Assignments
0 Petitions
Accused Products
Abstract
A system and method for reducing RH cycling of the membranes in a fuel cell stack. A control algorithm damps a power request signal using a first order filter during low power transients so that the fuel cell stack continues generating power at a higher rate than is requested. The excess power generated by the stack is used to recharge a battery in the fuel cell system. The damped power signal is weighted so that more fuel cell stack power is provided for a low battery state of charge unless stack power is provided for a high battery state of charge.
-
Citations
19 Claims
-
1. A fuel cell system comprising:
-
a fuel cell stack; a power source; and a controller, responsive to a power request signal, said controller including a damping filter that damps the power request signal over a damping time during a low power transient and provides a damped power demand signal to the fuel cell stack that provides more power than the power request signal during the damping time; and wherein the controller is further responsive to a power source state of charge signal, said controller including a state of charge weighting factor look-up table that provides a state of charge multiplier factor depending on the power source state of charge, said controller multiplying the weighting factor by the damped power demand signal to increase or decrease the damped power demand signal depending on the state of charge of the power source, wherein excess power generated by the fuel cell stack above the power request signal is used to charge the power source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A hybrid fuel cell system comprising:
-
a fuel cell stack; a battery; and a controller responsive to a power request signal and a battery state of charge signal, said controller including a damping filter that damps the power request signal over a damping time during a low power transient and provides a damped power demand signal that provides more power than the power request signal during the damping time, said controller further including a state of charge weighting factor look-up table that provides a multiplier factor depending on the battery state of charge, said controller multiplying the weighting factor by the damped power demand signal to increase or decrease the damped power demand signal depending on the state of charge of the battery, wherein excess power generated by the fuel cell stack above the power request signal is used to charge the battery. - View Dependent Claims (10, 11, 12, 13, 14)
-
-
15. A method for providing a power demand signal to a fuel cell stack in a fuel cell system, said method comprising:
-
operating the fuel cell stack at a higher power than a desired power request during a low power transient, wherein operating the fuel cell stack includes damping a power request signal during the low power transient over a damping time so that the fuel cell stack provides more power than the power request signal during the damping time, and weighting the damped power request signal depending on the state of charge of the battery, wherein weighting the damped power request signal includes multiplying the damped power request signal by a value greater than 1 if the battery state of charge is less than an optimal state of charge and multiplying the power request signal by a value less than 1 if the battery state of charge is greater than the optimal state of charge; and using the excess stack power to charge a battery. - View Dependent Claims (16, 17, 18, 19)
-
Specification