PEMFC air loop model and control

This paper presents the control of air supply of a proton exchange membrane fuel cell-PEMFC-system. This control is based on a species balance model in the cathode (oxygen) compartment which must be controlled to stay not only at a constant pressure but also to follow a desired air flow. Desired air flow combined with sufficient hydrogen flow enables the production of a maximal desired current for electrical load. In the context of a transport application (Tramway in this paper) pressure is increased from atmosphere to 1.5 bar absolute, with a controlled compressor. The moto-compressor group is based on a screw type compressor driven with a permanent magnet synchronous machine fed with a pulse width modulation inverter. The non linear drive control structure is described and the compressor characteristics is used to have an accurate control of the air loop supply allowing to let the fuel cell in their own settings and to furnish power following the desired power profile.