An impact of controlling energy management system via hybrid battery-supercapacitor in electric vehicles

Abstract

The characteristic of battery that has low power capacity cause the overall performance of an electric vehicle (EV) with single energy supply is not optimal. Thus, the EV system need to uses a battery as a primary energy source and combined with a supercapacitor that acts as a buffer system to provide a desired power to the load. However, the power that being supplied by both battery and supercapacitor must be controlled to prevent a high current drawing from the battery. This paper investigate the impact of controlling hybrid energy storage system (between battery and supercapacitor) to the lifetime of battery in EV. Both energy sources are interfaced with a unidirectional/bidirectional DC–DC converter. The MATLAB simulations are carried out to analyze the state-of-charging (SOC) for the battery and supercapacitor for a random driving cycle. The results show that the highest SOC in battery can be achieved when the multiplier in energy limiter is set to 100% and followed by 70% and 50%. The supercapacitor still able to fulfill the remaining load after completed the 14 seconds of run time. Thus, with the knowledge on maximum energy limiter that can be set on controlling hybrid energy storage system, the lifetime of the battery can be extended and the performance of EV can be improved.