Dissymmetrical switching in the 4Q interlaced converters for high speed trains: THD analysis

This paper deals with the AC/DC conversion input stages of the high-speed trains, that employ IGBT four quadrant (4Q) converters. The analysis considers the possibility to interlace more converters, thanks to a dedicated control logic, in order to diminish the harmonic content in the absorbed current. The absolute THD is defined through the Fourier series analysis, considering the advantages achievable by the interlacing of more converters. In particular, in the real case the effects of dissymmetry due to real configurations of the power converters that can affect the advantages of interlacing practice among the various stages are taken into consideration. At the end dedicated simulations are presented.