Patent ID: 8512902

Claim:
A fuel cell system, comprising: a fuel cell stack, a fuel inlet and an oxidant inlet, a fuel outlet and an oxidant outlet for removing an anode exhaust and a cathode exhaust from the fuel cell stack, respectively, a conduit for communicating between an oxygen source and the oxygen inlet and a conduit for communicating between a fuel source and the fuel inlet, wherein the fuel outlet is fluidly connected to a high frequency pulse-width modulated (PWM) purge valve, wherein the purge valve is configured to open for purges at a frequency of equal to or greater than 10 Hz, and wherein the ratio of the open time interval to the closed time interval ranges from 2%:98% to 98%:2% for any given frequency, a detector for detecting at least one operational characteristic of at least one fuel cell in the fuel cell stack, and a controller for controlling at least one operating parameter of the high frequency purge valve based on an input from the detector relating to the at least one detected operational characteristic.