Comparison of Fuel Cell Hybrid Propulsion Topologies with Super-Capacitor

Electric and hybrid electric vehicles are possible solutions to reduce the air-pollution and oil dependence of the transportation sector [1,2]. The fuel cell electric vehicle is currently considered to be the car of the future and consequently the automotive industry devotes great research effort and important resources to develop these technologies and to integrate them in their future vehicles. Hybrid electric propulsion systems are an interesting concept to increase the energy efficiency of the road transportation [3,4]. Peak power units (e.g. supercapacitors, flywheels...) can be introduced in the electric propulsion system to supply the peak power demands for vehicle acceleration [5,6]. This form of hybridisation of the electrical power system allows increasing the life-time of the main energy source in case of a battery-electric vehicle or allows improving or optimizing the dynamic performance of the energy storage system of fuel cell electric vehicles [7,8]. In this paper, several series hybrid propulsion system topologies are analysed on the basis of the simulation programme VSP. Especially the use of a DC/DC converter connected between the DC-bus and the fuel cell stack or the super capacitor or the use of 2 convertres are investigated.