Three-Phase Static Power Supplies for Air-Conditioned Electric Coaches using High Power GTO

The electrical design, characteristics, construction, and test results of a 170-kVA static power supply using 2500-V 600-A gate turn-off (GTO) thyristors developed for a wide range of electric railway applications are discussed. This power supply is principally composed of a thyristor chopper at an elementary frequency of 360 Hz and three-phase gate turn-off thyristor inverters in the form of a twelve-phase bridge configuration. It is capable of stabilizing a 60-Hz ac voltage and twelve-phase waveform. The bulk and weight of this power supply are ascribed to the avoidance of an inverter commutating circuit, which contains parasitic thyristors, capacitors, and inductances. The applied strategy is derived from the trend of the state of the art regarding switching cells and commuter trains.