Dynamic model of a dual active bridge suitable for solid state transformers

摘要

The Solid State Transformer (SST) is considered one of the most promising components in future energy systems. Its multiples advantages make it a promising solution in the future power grid when compared with the conventional fundamental-frequency transformer. Among different components, the Dual Active Bridge (DAB), consisting of two H-bridges and a high-frequency link, it is considered the key in the SST operation. In this paper a theoretical analysis to obtain the average and the small-signal models of the DAB is presented. Both models are used to design a PI controller to regulate the output voltage at the desired reference. Extensive time-domain simulations are carried out in order to validate the presented models. Results show that the output voltage follows the commanded reference under variations in the input voltage and the load current.