Optimal Design of the DAB as a Single Stage DC/DC Interface for Bidirectional DC Chargers

Abstract:
The wide range in common EV battery voltages results in wide output voltage range requirements for DC chargers. For cost reasons it is meaningful to realize this with a single isolated DC/DC converter. This paper proposes a design scheme for DABs that minimizes volume while maximizing efficiency over the complete input and output voltage range as well as for a large range of power transfer levels. The enabler for the wide voltage and power range at good efficiency levels is the utilization of triple phase shift modulation with variable switching frequencies and its application within the optimization routine.