Comparative analysis of dual active bridge isolated DC to DC converter with single phase shift and extended phase shift control techniques

Bidirectional energy transfer capability is the central part of a lot of modern power conversion systems. Preferably, for reduction of size, weight and cost these systems use a single high efficiency power electronic conversion system. A dual active bridge converter having two DC-AC converters connected back to back through an AC inductor/transformer is a common topology used for obtaining high efficiency bidirectional power conversion. Some characteristic features of the DAB converter topology are bidirectional power flow capability, inherent soft switching, high power density, high efficiency, galvanic isolation and low number of passive components. In this paper, circuit operation, design, and comparison of efficiency, switch stress, and closed loop operation for step load variation are discussed. Two common control strategies namely single phase shift, and extended phase shift are compared and respective waveforms are shown.