A Dual Active Bridge Based Single Phase AC to DC Power Electronic Transformer With Advanced Features

Abstract-Power Electronic Transformers (PET) offer the advantage of size and weight reduction compared to line frequency transformers by operating at much higher frequencies than line frequency. In this paper, a push-pull based AC/DC PET has been proposed and analyzed. The PET offers bidirectional power flow between single phase AC and DC, using the Dual Active Bridge (DAB) principle. Such a system may find applications in interfacing plug-in hybrid and electric vehicles to the grid. The proposed PET offers advantages of (a) open loop unity power factor operation, (b) soft-switching of secondary side converter power switches for all operating points, (c) high power density owing to use of a high frequency transformer and (d) high utilization factor, compared to previous work. Analysis has been done for power transfer, utilization factor and soft-switching. Simulation and experimental results have been provided to demonstrate the operation of the PET.