Utilizing Supercapacitors as A Primary Power Source for Electric Vehicle Motors During Urban Driving Cycles

Abstract

The energy consumption pattern of the Lithium-ion (Li-ion) battery bank in Electric Vehicles (EVs) exhibits rapid fluctuations for different driving cycles, leading to battery degra-dation and shortening its lifetime. Accordingly, the integration of supercapacitors (SC) in the EV energy management system helps in boosting its performance by distributing the motor load among the two energy sources. This work presents an energy management strategy for a hierarchical hybrid EV energy storage system (hHESS) that relies mainly on SCs to address the EV energy requirements during urban driving cycles with frequent accelerations and decelerations, while restricting the role of the EV battery to recharging the depleted SCs. This decreases the stress that would, otherwise, be imposed on the battery due to frequent variations in the motor's energy requirements. The New York City Cycle (NYCC) is used in this work to model a low-speed urban driving pattern with frequent stops, accelerations and decelerations. Observable improvements in the EV battery performance are noted when compared to utilizing traditional, battery-only operation during urban driving.