A Multiport Power Electronic Transformer Based on MMC with Resonant Circuit for DC Distribution

The existing power electronic transformer (PET) topologies based on modular multilevel converter (MMC) can provide multiple voltage ports. However, these PET topologies need four power conversion stages, which leads to complex circuit structure and large size. A multiport PET topology based on MMC with resonant circuit for DC distribution has been proposed in this paper. A mixed-frequency modulation strategy is adopted and a group of LC resonant circuit is connected in parallel with each MMC arm, to realize power decoupling between MVDC and LVDC ports. The proposed PET topology can provide the required four ports with only three power conversion stages, which has the advantages of simplified circuit structure and smaller size. Finally, the simulation results verify that the proposed PET is feasible and effective.