A Review on Power Electronic Transformer for High Speed Electric Locomotives
Railway is the one of the most popular and widely used ways for massive public transportation. The low-frequency line transformer in todays AC rail vehicles suffers from poor efficiency and a substantial weight. Future traction drives may operate directly from the mains without this transformer. To achieve high speed rail, a feasible concept by replacing line frequency transformer with medium frequency transformer ,thus by increasing the frequency of transformer will reduce the weight of transformer .A Power Electronic Transformer (PET) topology with multiport bidirectional resonant DC-DC converters is proposed where several medium-frequency multi-winding transformers is applied to realize the isolation. The power balancing could be realized by common flux linkage of the transformer and voltage balancing can be achieved by using optimization technique.The front end converter use high voltage IGBT based power switch with cascaded H bridge configuration and load end converter use various multilevel converter approach for feeding induction motor drives.
Keywords - Power Electronic Transformer (PET), Line Frequency Transformer (LFT), Medium Frequency Transformer (MFT), Internal Combustion Engine (IC)