A Preliminary Loss Comparison of Solid-State Transformers

in a Rail Application Employing Silicon Carbide (SiC) MOSFET Switches

The silicon carbide (SiC) power semiconductor and the medium frequency transformer (MFT) are two enabling technologies that are allowing the efficiencies and power densities of power electronic converters to be pushed beyond the limits of those that have previously been possible; the solidstate transformer (SST), with its viability based in part upon the two aforementioned technologies, has much potential to offer in Rail, Marine, Aviation and Smart-Grid applications due to its high performance operation and compact form-factor and so it is studied in-depth in this paper, where a comparison of the active and passive component losses between various SST topologies for a rail traction application, modelled with 3.3 kV and 10 kV SiC MOSFET switches alongside benchmark 3.3 kV and 6.5 kV Si IGBT switches, operating on a 50 Hz, 25 kV ac, overhead supply has been made. In addition, a comparative analysis is made of the estimated costs of the converters studied.