Simulation and performance analysis on an energy storage system for hybrid electric vehicle using ultracapacitor

Aiming at practical issues concerning high charging and discharging current as well as short cycle life of the energy storage system exposed on the hybrid electric vehicle (HEV) developed by First Automobile Works (FAW) presently, this paper presents a hybrid energy storage system using ultracapacitor which replace primary sole Ni-MH energy source, without any changes in other parts of HEV. Based on the energy flow of energy storage system and operating status of the vehicle, a control strategy taken internal combustion engine (ICE) into account was introduced. A specific amount of ultracapacitors was collocated. Simulation analysis shows that the charging and discharging current of the battery can be smoothed to some degree, especially apparently for peak regenerative feedback current. In addition, the charge-discharge number of the battery decreases obviously, which contributes to prolong service life of batteries.