Controller for Fuel Cell Operation

Abstract

The current invention is a fuel cell controller that includes a first control loop, where the first control loop is disposed to adjust a fuel cell current to regulate a hydrogen output pressure from the fuel cell to a pressure target valve, and further includes a second control loop disposed to adjust a hydrogen flow rate from a hydrogen generator to match a DC/DC power output to a power target value.

What is claimed is: 
     
         1 . A method for controlling a fuel cell system, comprising:
 at a first control loop, adjusting a fuel cell current to regulate a hydrogen output pressure from the fuel cell to a pressure target value; and   at a second control loop, adjusting a hydrogen flow rate from a hydrogen generator to match a fuel cell power output to a power target value.   
     
     
         2 . The method of  claim 1 , wherein the fuel cell is selected from the group consisting of a fuel cell, a fuel cell stack, and a fuel cell planar array. 
     
     
         3 . The method of  claim 1 , further comprising generating hydrogen at a generation rate by a hydrogen generator. 
     
     
         4 . The method of  claim 3 , further comprising providing the hydrogen to an inlet of the fuel cell, wherein adjusting a fuel cell current to regulate a hydrogen output pressure from the fuel cell to a pressure target value comprises:
 measuring a hydrogen output pressure at a purge valve fluidly connected to the fuel cell downstream from the inlet by a pressure transducer; and   generating a control signal using at least one of the measured pressure and the pressure target value by a pressure controller.   
     
     
         5 . The method of  claim 4 , further comprising adjusting a power output from the fuel cell by adjusting the fuel cell current pulled by a DC/DC converter based on the control signal and a voltage from the fuel cell, wherein adjusting a hydrogen flow rate from a hydrogen generator to match a fuel cell power output to a power target value comprises:
 monitoring the fuel cell current and voltage controlled by the DC/DC adjustable converter; and   adjusting the generation rate based on the power target value and the monitored current and voltage.   
     
     
         6 . A system for controlling a fuel cell system, comprising:
 a first control loop adjusting fuel cell current to regulate a hydrogen output pressure from the fuel cell to a pressure target value; and   a second control loop adjusting a hydrogen flow rate from a hydrogen generator to match a fuel cell power output to a power target value.   
     
     
         7 . The system of  claim 6 , wherein the first control loop comprises:
 a pressure monitor;   a pressure controller; and   a DC/DC converter.   
     
     
         8 . The system of  claim 6 , wherein the second control loop comprises:
 a DC/DC current and voltage monitor;   a hydrogen controller; and   a hydrogen generator.   
     
     
         9 . The system of  claim 8 , wherein the power target set point can be dynamically determined based on at least one of a current and/or predicted power draw from a load, state of charge of the system battery, remaining capacity of the hydrogen generator, and user input. 
     
     
         10 . The system of  claim 6 , wherein the first control loop maintains constant fuel pressure output and the second control loop regulates the system output power.