Single-phase UPFC Topology with Autotransformer Structure for Smart Grid

This paper proposes a topology for UPFCs. The proposed topology consists of N:2 transformer with a center-tap, a full-bridge converter and a half-bridge converter. While the conventional UPFC topology uses two three-phase transformers, which are called as a series transformer and a parallel transformer, the proposed topology uses three single-phase transformers. By using an autotransformer structure, the voltage ratings of the transformers and the switches in the power converter module can be decreased significantly. As a result, compared to the conventional UPFC topology, it is possible to reduce installation spaces and costs. Also, by adopting a full-bridge converter and a half-bridge converter structure, the proposed topology can be easily implemented with the conventional power devices and control techniques. Simulations and experiments were performed and, the results verify the effectiveness of the proposed UPFC topology.