Patent ID: 6388904
Filing Date: 2002-05-14
Classification: H02M

Abstract:
A power supply device for an electromotive railcar, comprising:a plurality of first capacitors connected in series and adapted to receive a first DC voltage across said series connected capacitors from an electric power line; a plurality of DC/AC/DC converters, each of said DC/AC/DC converters including an inverter bridge with an input of said inverter bridge connected in parallel to one of said 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 said inverter bridge, and a rectifier circuit connected to a secondary winding of said insulating transformer to output a DC voltage; a smoothing circuit including a DC reactor a second capacitor for smoothing the DC voltages output from said rectifier circuits of said DC/AC/DC converters, said smoothing circuit generating a second DC voltage; a three-phase inverter including a bridge circuit having a plurality of power transistors, said three-phase inverter generating a three-phase AC voltage on the basis of said second DC voltage; and an AC filter connected to an output of said three-phase inverter and including a series connected circuit comprising an AC reactor and an AC capacitor, wherein one terminal of said AC capacitor is connected to a neutral point of said secondary winding of said insulating transformer, and wherein respective outputs of the rectifier circuits of said DC/AC/DC converters are connected to each other in parallel.