Abstract: A method and apparatus for providing a substantially constant output voltage from a fuel cell, notwithstanding output current variations, is disclosed. The voltage and secondarily the current of the cell is determined at least periodically. The pressure of the reactant gas in the fuel cell is then regulated so substantially the nominal voltage is maintained. The temperature in the fuel cell may also be regulated to maintain the nominal output voltage. Also, a method and apparatus for minimizing the parasitic power drain in a electric power generation system is disclosed. The fuel cell is fed with an reactant gas by a compressor driven by parasitic power drawn from the fuel cell.

Abstract: A method and apparatus for monitoring the performance of fuel cells arranged in series. More particularly, the method and apparatus involve the measurement and comparison of fuel cell performance indicators, such as voltage, in groups of cells connected in series. In a first embodiment, the voltage across each fuel cell group is compared to a reference voltage equal to a predetermined minimum voltage. In a second embodiment, the voltage across each group is compared to a reference voltage equal to the average across all fuel cell groups. In a third embodiment, a reference voltage equal to the voltage across one group is compared to the voltage across each of the other fuel cell groups. In a fourth embodiment, the voltage across each group is compared as a reference voltage to the voltage across an adjacent fuel cell group. Other embodiments comprising various combinations of the first, second, third and fourth embodiments are also provided.