The design and testing of a purely supercapacitor energy storage device as auxiliary powersource in electrical vehicle applications having a PEM fuel cell as main source are presented.The two control strategies are explained. The control algorithms are that fuel cell is simplyoperating in almost steady state conditions in order to lessen the mechanical stresses of fuelcell and to ensure a good synchronization between fuel flow and fuel cell current.Supercapacitors are functioning during absence of energy from fuel cell, transient energydelivery or transient energy recovery.The system utilizes two modules of SAFT supercapacitive storage device. This device isconnected to a 42 V DC bus by a 2-quadrant dc/dc converter, and fuel cell is connected to thedc bus by a boost converter. The system structure is realized by analogical current loops anddigital control (dSPACE) for voltage loops and estimation algorithms. Experimental resultswith a 500 W PEM fuel cell point out the slow dynamics naturally of fuel cell because ofthermodynamic and mechanical operation, and also substantiate that the supercapacitors canimprove dynamics and power conditioning for automotive electrical system.
