For overcoming the uncertainty of a single DC microgrid powered by renewable energy

multiple DC microgrids can be connected through an interconnection converter to form a DC microgrid interconnection system. For this system

a two-stage interconnection converter for connecting DC microgrids with different voltage levels is designed. The front stage of the interconnected converter adopts a three-phase LLC resonant converter topology

which plays a role of electrical isolation and efficient power transmission. At the same time

the transformer uses Y-Y connection mode to reduce the voltage stress on the primary and secondary sides and reduce the output current ripple. While

the latter-stage bidirectional DC converter adopts interleaving technology to reduce switching loss and conduction loss. Finally

the control strategy of the interconnected converter is introduced. Modeling and simulation are performed in Matlab/Simulink. The correctness of the designed converter is verified by the simulation result. The comparison with the DAB converter proves that the designed interconnected converter

in case of heavy load operation

has higher operating efficiency.