Energy Management of an Electric City Bus with Battery/Ultra-Capacitor HESS

Aiming at the problems about the short driving range of the electrical vehicle, in this paper, the ultra-capacitor is inserted into the control system, then a pure electric city bus with the proposed hybrid energy storage system (HESS) produced by CENS Energy Tech Co. is taken an example, the reasonable configuration model of the power system is modelled in MATLAB-CRUISE, the power flow analysis on Harr wavelet-transforming is proposed, the simulation results show the batteries can be protected and avoided from being charged and discharged excessively, the SOC of the battery is relatively stable, the braking energy can be recovery, the vehicle performance can be improved and the battery lifetime can be prolonged.