Comparing DC-DC converters for power management in hybrid electric vehicles

The design of DC-DC converters for power electronic interfaces in power management systems for hybrid electric vehicle (HEV) is a very challenging task. To this end, this paper presents an analysis, design, and comparison study of several bi-directional non-isolated DC-DC converter topologies that could be considered potential candidates for the power electronic interface of HEV energy/power sources, in particular an ultracapacitor pack. The considered topologies are the half-bridge, Cuk, SEPIC, and Luo converters. The analysis and design of the converters is performed throughout equations for the stresses of the active and passive components. The comparison study, achieved by means of graphs where the variables of interest are plotted as a function of the voltage ratio Vo/Vi, uses the half-bridge converter as the base case. Particular attention is paid to the stresses of the active and passive components due to the wide input voltage requirements typical of this load-leveling or power-management application.