Bi-directional AC-DC converter for distributed DC power system with wide bus voltage

Distributed DC Power System is easy to integrate the renewable resources, and improve the efficiency of power generating and power supplying, it draws attentions from all over the world. However, the system structures and the bus voltage range of the Distributed DC Power System are lacking of the standards and specifications, and this makes it hard to design the power electronics devices. To accommodate the Distributed DC Power System with wide bus voltage (260~400V), a bidirectional AC-DC converter consisted of dual active bridge (DAB) converter cascaded with full bridge inverter is studied in this paper. For the DAB stage, the wide bus can be converted to rated 400V by phase shift control strategy to fulfill the requirement of the inverter stage which is controlled by SPWM strategy. The working principle is analyzed, and a 3kW prototype is designed. From the experiment result, this bidirectional AC-DC converter can fulfill the demands of the power system with wide bus to trade off power, bi-directionally, with the grid.