0On the Control of Automotive Traction PEM Fuel Cell Systems

A fuel cell (FC) is an electro-chemical device that converts chemical energy to electrical energy by combining a gaseous fuel and oxidizer. Lately, new advances in membrane material, reduced usage of noble metal catalysts, and efficient power electronics have put the fuel cell system under the spotlight as a direct generator for electricity (Pukrushpan, Stefanopoulou & Peng, 2004a). Because they can reach efficiencies of above 60 % (Brinkman, 2002),(Davis et al., 2003) at normal operating conditions, Proton Exchange Membrane (PEM) fuel cells may represent a valid choice for automotive applications in the near future (Thijssen & Teagan, 2002), (Bernay et al., 2002). Compared to internal combustion engines (ICEs) or batteries, fuel cells (FCs) have several advantages. The main advantages are efficiency, low emissions, and dual use technology. FCs are more efficient than ICEs, since they directly convert fuel energy to electrical energy, whereas ICEs need to convert the fuel energy to thermal energy first, then to mechanical energy. Due to the thermal energy involved, the ICE conversion of energy is limited by the Carnot Cycle, not the case with FCs (Thomas & Zalbowitz, 2000). Fuel cells are considered zero emission power generators if pure hydrogen is used as fuel