A New Method for Modeling Bidirectional Buck-boost Converter by using a New Form of Signal Flow Graph in order to Employ in Energy Management System of an Electric Vehicle

In this paper, a new form of signal flow graph technique is used for modeling a bidirectional buck-boost converter and extracting the needed transfer functions. The signal flow graph method has a more simple process in comparison with other modeling techniques. The modeled converter is employed in energy management system of an electric vehicle. The energy system of the electric vehicle is composed of two energy sources; ultra-capacitor and battery pack. The proposed hybrid source has the advantages like: high energy density transmission and high instantaneous power output on the ultra-capacitor. Here, by using the mentioned converter, the energy management between the two sources is performed. Furthermore, the needed configuration for energy management system is presented and a proper controller based on obtained model for energy management in hybrid sources is proposed. Finally, the simulation results are brought to verify the precision of the proposed modeling technique and effectiveness of it in energy management system of an electric vehicle.