Current control of a PEMFC system connected to an electrical load through a DC/DC converter

Polymer electrolyte membrane fuel cells are highly efficient energy converters with water and heat as the only reaction products when hydrogen is used as fuel. As compared to auxiliary power units that are currently used for power generation on aircrafts, the fuel cell technology has the potential of significantly reducing emissions and noise. Applications such as power generation, water production and the use of the byproduct oxygen depleted exhaust air are part of the multifunctional use of the fuel cell technology. Cathode exhaust air having the correct oxygen concentration can be utilized such as for kerosene tank inerting. For a given air mass flow provided by the compressor as the fuel cell air supply system a certain oxygen concentration establishes depending on the stack current consumed. In this study a self-powered fuel cell system is connected to an electrical load through a dc/dc converter. As the dc/dc converter parameters are not exactly known a feedforward control of the load current would unavoidably lead to drawing too much or too little fuel cell current. A controller architecture that accounts for the correct consumption of fuel cell current is presented here.