This paper presents a design method of a solid-state transformer (SST) for medium-voltage direct current (MVDC) Application. The
traditional low frequency transformer requires a huge volume and weight to adopt for high-power and medium-voltage application.
With growth of the power electronics technology, the solid-state switch based DC transformer became attractive candidate for DC
distribution field. In this paper, the classification of SST topologies are introduced and a novel SST architecture is presented which is
composed of modular converters. The various simulation results verify the effectiveness of the proposed SST design and its control
strategy.