Solid State Transformers (SST) are highly attractive both in industry and academia as they provide interface between medium-voltage AC (or DC) grids and low-voltage AC (or DC) grids and bring the benefits of modularity, flexibility, scalability, smaller footprint, less weight, bidirectional power flow and high-power quality to the units at the grid connection. Back in the 1990s they were attractive in the industry mainly to reduce weight and volume of the AC/DC converters in the rail applications. However, the interest in SST decreased due to its complex design and lower efficiency compared to conventional transformers.
In the last two decades the increasing DC applications in the area of Electric Mobility, Renewable Energy, Smart Grids, Datacenters and DC Microgrids brought back the interest to SST systems. Various topologies and control methods were proposed, and several demonstrators have been developed since then.
In this tutorial an SST overview will be shared with the audience and design criteria will be explained.
