A Flexible Non-Isolated Multiport Converter to Integrate Battery and Ultracapacitor for Electric Vehicle Applications

In order to maximize the utilization of battery and ultracapacitor (UC) in a hybrid energy storage system (HESS) for electric vehicle (EV) applications, a DC-DC power electronic interface with proper management of power flow is very crucial. Aiming at this, a non-isolated two input and one output multiport converter configuration, which is capable of achieving dynamic flexibility in power flow while meeting fluctuating load demands of an EV is proposed. The converter provides dedicated power flow paths for high and low currents, which can be flexibly reallocated according to the load current and voltage level of the energy sources. This eventually facilitates in maneuvering the flow of power by dynamically allocating the desired energy source with the appropriate current flow path. Moreover, the proposed converter offers bidirectional power transfer capability for all the ports and allows single stage power conversion in every possible power flow combinations. The converter configuration along with different operating modes and control strategy are discussed and the performance is validated through experimentation using a laboratory scale hardware prototype.