Design and implementation of a smart solid-state transformer based power converter for solar PV system

Solid state transformer (SST) is considered as an emerging technology for efficient and flexible grid integration of renewable and distributed energy sources. This paper presents design and implementation of a smart SST based power electronic converter that enables efficient grid integration of solar photovoltaic (PV) system. The designed prototype includes solar PV module, SST with dual active bridges (DAB), inverter and LCL filter. The proposed SST based system with associated controllers are implemented in Matlab/SimpowerSystem and a smaller prototype is developed using the required hardware and dSpace DSP system. The simulation and experimental results confirm that the designed SST based converter system can integrate solar PV module into grid efficiently, with the LCL filter showing good reduction of unwanted harmonics. The use of high-frequency transformer and SST provide cost savings and further avenues of control to a high-power converter through reduction in transformer size and cost, taking advantage of current pulse shaping to dictate power transfer characteristics and direction. The SST with dual active bridge increases in efficiency and power transfer depending on the relative phase angle between each Active Bridge switching.