Comparative analysis of single and three-phase dual active bridge bidirectional DC-DC converters

Many modern power conversion systems require a bi-directional energy transfer capability as a central part of their system operation. Preferably, such systems should use a single high efficiency power electronic conversion system to reduce size, weight and cost. For higher power bi-directional conversion, the common topology proposed is a dual active bridge structure, where two DC-AC converters are coupled back-to-back through an AC inductor/transformer. Either single-phase or three-phase converters have been proposed for such a system, but to date no clear-cut basis for selecting between these two alternatives has been established. This paper presents a comparative evaluation of single and three-phase back-to-back converters for use in a bi-directional power transfer application. The paper considers these two alternatives from the perspective of operating performance and losses, and provides a basis for selecting between the two topologies in any particular operating context.