Design and comprehensive modelling of solid-state transformer(SST) based substation

The concept of Solid-State Transformer (SST) is a subject of vivid attention and extensive research in the recent decade, motivated by their potential impact extending well beyond 50 Hz transformers for power distributions. With the introduction of wide band-gap semiconductor devices such as GaN and SiC, it is starting to look more likely to see SST in field applications in the near future. This paper proposes the design of a compact 10 kVA, Solid State Transformer(SST) based substation. The design employs a dual active bridge (DAB) converter to achieve the bi-directional power flow and zero voltage switching (ZVS) in the switching devices, operated at 50 kHz switching frequency. Comprehensive modelling of the high frequency transformer is presented by considering the multiple core PCB configuration. A 2-D electromagnetic analysis is used to estimate the parameters of high frequency transformer which is implemented in a finite-element analysis software. J-A model of a hysteresis loop is also introduced to predict the magnetic hysteresis behaviour of the high frequency transformer accurately. To support the presented concept, simulation results from Matlab-Simulink tool are shown and discussed.