An Evaluation Study of Hybrid Energy Storage System for Plug-In Hybrid Electric Buses

This paper reviews different configurations of the hybrid-energy-storage-system (HESS), a combination of Li-ion Battery (LiB) pack, Li-ion capacitor (LiC) bank, and dc-dc converters, for Plug-in hybrid electric (PHE) buses. A new HESS configuration is proposed to improve the efficiency of power transfer from battery port and reduce the rating voltage of LiC bank associated the cell balancing problem. The simulation results with a standard SORT driving cycle will be used to optimize the sizing of LiB and LiC packs. The comparative analysis illustrates that the proposed configuration has several merits against the conventional hybrid topology based on high-energy batteries and electrical double-layer capacitors in term of weight and volume.