Power supply device for electromotive railcar

Abstract

A power supply device for an electromotive railcar, including a series circuit composed of a plurality of first capacitors, connected to receive a first DC voltage from an electric power line; a plurality of DC/AC/DC converters. Each of the DC/AC/DC converters including an inverter bridge with an input thereof connected in parallel to one of the first capacitors and having a plurality of power transistors, an insulating transformer with a high carrier frequency and having a primary winding connected to an output of the inverter bridge, and a rectifier circuit connected to a secondary winding of the insulating transformer to output a DC voltage. The power supply device further including a smoothing circuit including a DC reactor and a second capacitor for smoothing the DC voltages output from the rectifier circuits of the DC/AC/DC converters, the smoothing circuit generating a second DC voltage; and a three-phase inverter including a bridge circuit having a plurality of power transistors, the three-phase inverter generating a three-phase AC voltage on the basis of the second DC voltage. The respective outputs of the rectifier circuits of the DC/AC/DC converters are connected to each other in parallel.