Robust energy management of a battery/supercapacitor Hybrid Energy Storage System in an electric vehicle

Abstract

Batteries are considered to be one of the key components in EV. Although the energy density in batteries has continuously been evolving, they can be easily damaged by the peak current or steep variation of current. In order to overcome this weakness, an active battery/supercapacitor (SC) Hybrid Energy Storage System (HESS) has been proposed. The major problem concerning an active HESS in EV is in how to control the current flow in order to minimize the magnitude/ fluctuation of the current flowing in and out of the battery of EV. It is well known that future load profiles can be used to obtain more optimal control of current flow in EV. However, it is difficult to acquire the accurate load profiles because the vehicle movement relies on many factors, e.g., the traffic on the road or the driving pattern of a driver. In this paper, we propose an optimization framework for computing the sub-optimal current flow of the HESS in EV although the future load profile is not precise. Simulation results show that the proposed scheme can efficiently minimize the magnitude/fluctuation of the battery current in EV.