Design and simulation studies of battery-supercapacitor hybrid energy storage system for improved performances of traction system of solar vehicle

Energy storage systems of Solar Vehicles require high energy density and high power density concurrently. The best solution is using supercapacitor (SC) during rapid power changes and in the recovery of braking energy to ameliorate solar vehicle autonomy. SCs can also keep batteries charged for extended durations and can be used to store the excess energy generated by photovoltaic panels. In this study, the power management of the electric traction system of the solar vehicle is insured by the hybridization of SCs and batteries to minimize the effects of peak current demands on the battery driving cycle. The efficiency of the overall system can be improved by the proposed hybrid storage system. The simulation results verify that integration of the SC into the photovoltaic energy storage system of the solar vehicle is effective in decreasing the battery stresses and eliminating the peak currents in the battery pack, thereby increasing the battery's life span. The use of SCs decreases the fluctuation in the direct current (DC) bus voltage during rapid motor speed changes and the photovoltaic fluctuations and provides a speed that is closest to the desired reference speed. A hardware design approach used for a small-scale prototype to proof the efficiency of the EMS and the distribution energy between batteries and SCs. It validated by three simulation tests.