A three-phase 10 kVAC-750 VDC power electronic transformer for smart distribution grid

In this paper, a power electronic transformer (PET) topology for distribution grid is presented based on modular multilevel converter (MMC). The presented topology is of three-phase type and have two dc voltage terminals, i.e. the high-voltage dc terminal and the low-voltage dc terminal. So, it can be connected directly to high-voltage direct current (HVDC) systems and renewable energy systems simultaneously. This feature makes it possible to perform as an “energy router” in smart grids. What is more important, the proposed PET can substantially reduce (by 44.4% for the studied case) the number of medium frequency transformers (MFTs), compared with the existing solutions. Computer simulation and experimental results on a 10 kV prototype show validity of this PET.