High Power Density Laboratory Prototype of Single-Phase Solid-State Transformer

Ever since the rise in infiltration of renewable sources into the modern electric grids, the concept of solid-state transformer (SST) has garnered special attention to dynamically control and regulate the power flow while preserving the quality of supply. Though SSTs are capable of catering to a myriad of service demands by customers, their complex multistage architecture, large device count, complexity in control, increased device losses and relatively higher cost remain major bottlenecks for their widespread market penetration. This paper is intended to address the major impediments mentioned above by proposing a simple three-stage, modular architecture for SST with a minimal switch count, high power density and input power factor correction for low power applications. Each stage of SST is equipped with independent, simple and robust controllers contributing to high degree of modularity. A 1 kVA laboratory prototype is built for supplying power to sensitive electric equipment and the results presented in support of the proposed architecture. The developed prototype is shown to have unity power factor at the input, less than 10 percent of the weight and more than thrice the power density relative to the conventional transformer of similar rating.