A New Multi-Port Power Electronic Transformer for Distribution Grid

A new multi-port power electronic transformer (PET) for distribution grid is presented in this paper. The proposed PET includes high voltage stage, isolation stage and low voltage stage, which can provide high voltage DC port, high voltage AC port, low voltage DC port and low voltage AC port. The high voltage stage adopts three-phase four arms Modular Multilevel Converter (MMC) structure, which can reduce the number of sub-modules and associated elements compared with three-phase six arms MMC. The third phase of three-phase four arms MMC consists of batteries in order to achieve energy storage capability.