PET applicable to 3-phase medium-voltage AC grid with DC bus self-balancing capacity

Abstract

This paper proposed a new Power Electronic Transformer (PET) topology in medium and high voltage application of 3-phase AC distribution network. In the proposed topology, diode clamped multilevel converter is used as the rectifier stage, and input series output parallel (ISOP) Dual Active Bridges are adopted for isolated voltage conversion. The proposed topology is suitable for medium and high voltage levels, and has relatively small volume compared to other applicable topologies and self-balancing capability of HVDC capacitor voltage. A decoupled control strategy is used in the proposed PET system. Stimulations have been done to prove the feasibility of the topology. Results show that the voltage of HVDC bus capacitor in the new PET topology can be well balanced.