A PET-based on Vienna rectifier Research on New Topological Structure and Control Strategy

Abstract

Power Electronic Transformer (PET) has received extensive attention and research due to its high stability, flexible control, and low "pollution" to the power grid. Existing PET uses fully controlled switching devices with a single output level. To solve this problem, a new PET topology based on the Vienna rectifier is proposed in the article. The isolation stage uses Vienna rectifiers. As the number of levels increases, not only can the switching frequency of power devices be increased, but also system losses can be reduced. In this paper, the new PET topology based on the Vienna rectifier is established, using the current inner loop and voltage outer loop dual closed-loop PI control strategy, and building a Simulink simulation model. The simulation results show that the voltage of the PET input stage is increased by 60% after rectification, and the voltage fluctuation is stable within the range of 1 %, which meets the requirements of the power grid. The three-phase voltage and current are symmetrical, and the power factor is close to 1, which meets national standards.