Solid-state transformers of smart high-power battery charger for electric vehicles

Smart bidirectional high-power electric vehicles charger can be based on Solid-State transformers (SSTs). A specific design of a low-cost smart charger is proposed using a medium frequency transformer based on a wound core made with Grain Oriented Electrical Steel (GOES) operating at medium frequencies and a temperature higher than coil ones. The preliminary study, based on core losses measurements made with rectangular and sine voltages, proves that the best case is the simplest possible converters producing rectangular voltages. Experimental investigations made on a smaller transformer of the same structure provide data for designing the 350 kVA transformer coils and estimating the efficiency.