Dynamic fuel cell system management controller
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Accused Products
Abstract
A method and system for dynamically controlling and managing a fuel cell system is provided. The method and system ensures that predetermined operating parameters and conditions are met. This is achieved using programmable on-board hardware that is already available in the fuel cell system and does not require additional components. More specifically, operating characteristics are measured such as the voltage of the weakest cell, the stack output voltage, the stack output current, the current of a battery being charged by the stack and/or the power of the stack. When each of these measurements is taken, a determination is made to find the load change that should be made in order to adjust the stack voltage to achieve a desired goal. In particular, the load on the fuel cell system can be varied by adjusting the duty cycle of the switches within a DC-DC converter that is being operated by an associated microcontroller. Measurements can also be used to measure methanol concentration and to predict optimal points at which a dosing of additional fuel should be delivered to the fuel cell system.
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Citations
20 Claims
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1-9. -9. (canceled)
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10. A method of dynamically controlling and managing operating characteristics of a fuel cell system, including the steps of:
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(A) providing a DC-DC converter circuit having an input connection to receive the output of a fuel cell, and connected to place a load across the fuel cell, said DC-DC converter circuit having internal switches that are operated at a duty cycle that is adjustable;
(B) providing a programmable controller that receives as an input, present and stored values of one or more operating characteristics, said programmable controller also being programmed to signal said DC-DC converter switches to adjust its duty cycle;
(C) dynamically determining a desired value for one or more operating characteristics of the fuel cell system, depending upon the operating conditions of the fuel cell system;
(D) monitoring one or more operating characteristics of said fuel cell system;
(E) calculating a new duty cycle for the associated DC-DC converter within the fuel cell system required to substantially achieve the desired value for one or more of said operating characteristics; and
(F) signaling said DC-DC converter to adjust its duty cycle to said new duty cycle. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of controlling a fuel cell system, including the steps of:
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(A) dynamically determining desired values for a plurality of operating characteristics being monitored in a current mode of operation of a fuel cell system;
(B) measuring each of said selected operating characteristics;
(C) determining a duty cycle required to substantially achieve each individual desired value and storing each duty cycle;
(D) comparing stored values and selecting the minimum duty cycle; and
(E) using this duty cycle as the new duty cycle of the DC-DC converter circuit switches within said fuel cell system;
- View Dependent Claims (17)
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18. A method of measuring fuel cell concentration in a fuel cell system:
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(A) identifying the weakest fuel cell in a fuel cell stack;
(B) increasing the overall stack output current until the voltage of the weakest fuel cell approaches zero;
(C) measuring the stack output current as a limiting current;
(D) determining whether concentration is too high or too low, based on the measured current value; and
(E) dosing additional fuel or water should a desired value not be met.
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19. A method of dynamically controlling and managing temperature in a fuel cell system, including the steps of:
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(A) measuring the stack output voltage of the fuel cell system;
(B) determining whether the stack output voltage is at a desired value depending upon the present desired temperature range of the fuel cell system, for the present operating conditions, and (C) adjusting the duty cycle of an associated DC-DC converter to change the output stack voltage to substantially the desired value.
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20. A method of dynamically controlling the output power of a fuel cell system including the steps of:
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(A) dynamically determining a desired value for the output power of the fuel cell system, depending upon the present operating conditions of the fuel cell system;
(B) measuring the output power of the fuel cell system;
(C) if the desired value is not substantially met, measuring fuel cell concentration;
(D) adjusting fuel cell concentration to substantially achieve the desired value of the output power of the fuel cell system; and
(E) adjusting the overall stack voltage to substantially achieve the maximum output power of the fuel cell system.
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Specification