Electro-thermal sizing of supercapacitor stack for an electrical bus: Bond graph approach

This paper is devoted to the study of electro-thermal sizing of supercapacitors stack. The application concern the alimentation of trolleybus in case of electrical microcuts that frequently occurs during circulation of the trolleybus. The goal is to size the number of supercapacitor to be implemented knowing the speed and acceleration profile of the trolleybus and to discuss about the thermal performance of the obtained stack. Based on bond graph approach, direct and inverse model of the kinematic chain of trolleybus is developed in order to deduce the consumption of an electrical bus and the braking energy in relation with the speed profile. Validation of direct model has been carried out with experimental results. Then, based on the Ragone plot of supercapacitors, we study the number of supercapacitors needed to recover braking energy and to supply the bus in the case of electrical microcuts. Finally, A bond graph thermal model of the stack is developed and the efficiency of this model is validated based on experimental results on a test bench.