Power Electronic Transformer based DC Network for Household Applications

DC network is a desired solution to cater for the increasing penetration of DC-compatible energy sources, storages and loads. This paper proposes a novel topology of DC network in reference to the conventional AC transmission/distribution network, where there are multiple DC subgrids with same or different nominal voltages interconnected to the common bus by DC Transformer (DCT). Different voltage levels have been set in the DC network with considerations of compatibility, power loss, voltage drop, distribution distance, etc. DCT is proposed to substitute the conventional power converter for bus voltage regulation and galvanic isolation. Compared with various topologies and CLLC-type has been recommended due to its capabilities of bidirectional power flow, seamless transition and low switching loss. Different operation scenarios for the DCT of the DC network has been analyzed. DCT is designed in order to maximize the conversion efficiency and minimize output voltage variations in different conditions. The models of DCT and its implementation in the proposed DC network have been developed in Matlab/Simulink. The performances of system under different operation conditions have been confirmed.