The traditional power electronic transformer(PET)based on modular multilevel converter(MMC)with half-bridge submodule uses a large number of switching devices and passive components

which limits its power density and efficiency. A topology of PET based on MMC with H-bridge submodule and input series output parallel(ISOP)DC-DC converter is proposed

which can generate a low level medium-voltage DC bus to reduce the number of DC-DC modules and realize self-blocking when a fault occurs. An indirect series of ISOP converter structure is proposed

when the medium voltage DC port is short-circuit

the short-circuit discharge of the input side capacitor of DC-DC converter can be effectively avoided by changing the connection mode of the input side of DC-DC converter. The numbers of switching devices

passive components

high-frequency transformers and DC-DC converter modules can be effectively reduced

and the power density

efficiency and fault ride-through ability can be effectively improved by the proposed PET. Finally

the simulation model of the proposed PET is built based on MATLAB/Simulink

and the feasibility of this topology is verified by the simulation results.