Transformer less Intelligent Power Substation design with 15kV SiC IGBT for grid interconnection

Basic power topology for a Solid State Transformer (SST) with new 15kV SiC IGBT devices is discussed. It is difficult to build high efficient, light weight, magnetically isolated solid state transformer for high voltage (13.8 kV) grid connectivity with existing Si 6.5kV rated IGBTs and diodes. Existing state of the art high voltage (6.5kV), high speed power devices (IGBT) cause considerable amount of loss (switching and conduction loss). With the advent of SiC devices these limitations are largely mitigated and this provides the motivation for new power topologies. The targeted efficiency of the proposed SST is 98%.Simulation results for a 1 MVA proposed SST topology is presented.