Supercapacitors for power assistance in hybrid power source with fuel cell

This paper deals with the use of supercapacitors as ancillary power supply in transport applications powered by a PEM fuel cell. These applications are known for strong transient power demand which makes supercapacitors a relevant choice. The aim of this association and its associated power management is to guarantee load requirements as well as to minimize fuel consumption and to ensures that each component constraint is satisfied (lifetime, reliability, high efficiency, ...). The designed strategy uses a cascade control allowing a frequency decomposition of the power demand cycle: supercapacitors supply the high band of the load power frequency spectrum whereas low frequencies are provided by the fuel cell which contributes to the longterm autonomy. An experimental 1 kW power test bench has been designed to illustrate the effectiveness of the proposed method. Experimental results are presented demonstrating that this approach provides improvements in terms of a significant energy savings when ancillary power supply is implemented.