Multiple input integrated DC/DC converters and supervisery control for fuel cell/battery/ultracapacitor electric vehicle

In this paper, a new multiple-input DC/DC integrated converter is proposed for a fuel cell/battery/ultracapacitor electric vehicle. The power density increases in the order of fuel cell, battery, and ultracapacitor and the energy density is reverse of the order. The proposed converter combines interleaved type boost converters and two parallel-connected bidirectional DC/DC converters. The advantages of the proposed converter topology are improved power density, due to the fact that a heavy power transformer is not used, and the state of charge of battery as well as that of the ultracapacitor can be controlled easily.