A Novel Adaptive Digital Filter-Based Energy Management Strategy Applied to Hybrid Energy Storage System for Electric Vehicles

This paper introduces a new hybrid energy storage system (HESS) and an adaptive digital filter-based energy management strategy (ADFBEMS) for electric vehicles (EVs). The HESS consists of a lithium-ion supercapacitor (SC) and a battery module. A synchronous rectification interleaved boost converter connects the SC to the battery module, enabling power distribution. The ADFBEMS employs a sliding discrete fast Fourier transform (SDFFT) to track the instantaneous load spectrum and a low-pass filter with adaptive cut-off frequency for load distribution based on frequency. The SCs handle the high-frequency load component, while the battery module supplies the remaining load. A MATLAB model is developed to validate the proposed HESS with ADFBEMS through hardware experiments using the worldwide harmonized light vehicles test cycle (WLTC) Class 1. Simulation and experimental results demonstrate the effectiveness of the proposed system by comparing it with the traditional fixed cut-off frequency energy management strategy. The proposed HESS with ADFBEMS reduces APstress and the high-frequency ratio (HFR) by 11.06% and 27.46%, respectively, contributing to an extended battery module lifetime.