Power Sharing and Energy Management between Supercapacitor and Battery in a Hybrid Energy System for EVs

Use of supercapacitors (SCs) in electric vehicles (EVs) is gaining popularity in the research community due to their high-power density and fast response. In this paper, a simple novel energy management strategy for a hybrid energy storage-based EV is proposed. The proposed strategy utilizes the inverse relationship of the instantaneous vehicle speed and the state of charge (SoC) of the SC to optimally manage the auxiliary power from SCs, improving the overall performance of the hybrid EV. This reduces stress on the traditional battery system by operating the SC during the high ramp rate power changes in the drive cycle. The proposed power sharing algorithm between the battery energy storage and SC is simple and requires very low computational burden compared to some of the more advanced optimal theory-based strategies previously proposed. The operation of the developed system is verified by a simulation study in Matlab/Simulink and the performance of an EV utilizing the proposed topology is analyzed using the Worldwide harmonized Light vehicles Test Cycle (WLTC) standard drive cycle.