A new strategy for battery and supercapacitor energy management for an urban electric vehicle

A new strategy of energy management between battery and supercapacitors for an urban electric vehicle is suggested in this paper. These two sources are connected in parallel to the DC bus through two bidirectional DC-DC converters enabling separate control over the power flow of each source. Vehicle dynamics with load torque applied on the shaft motor is to be considered. This strategy of energy management permits dividing energy between the two sources depending on the state of charge of each source as well as on the vehicle displacement state such as stopping, acceleration, cruising down and uphill, and deceleration. The aim of the proposed strategy is the best use of energy through maximizing the use of SCs by transferring energy from batteries to SCs during the standstill phase or when the load applied to the vehicle is small; supercapacitors will then be ready in critical situations such as rapid acceleration or in high hills climbing. In order to validate the control design and evaluate our energy management strategy performance, a simulation of an urban hybrid electric vehicle movement with the Matlab/Simulink software is implemented.