Voltage source type power converting apparatus

A voltage source type power converting apparatus for converting power between a multiple-phase AC system and a DC system, said voltage source type power converting apparatus comprising:

• a plurality of voltage source type reversible AC-DC power converter units having an AC side terminal and a DC side terminal, said voltage source type reversible AC-DC power converter units adapted to convert AC power to DC power and DC power to AC power, and consisting of a bridge connection of switching devices that have a self-ON-OFF switching function in a forward direction and a current passing function in a reverse direction, said switching devices of said bridge connection being connected between said AC side terminal and said DC side terminal, respectively, each DC side terminal being connected in series or in parallel;
• a capacitor or capacitors connected to said DC side terminal or DC side terminals of said voltage source type reversible AC-DC power converter units;
• and
• a phase-shifting transformer or phase-shifting transformers comprising a common multiple-phase primary winding or a group of parallel-connected multiple-phase primary windings being connected to said multiple-phase AC system, and comprising a group of multiple-phase secondary windings being connected to said AC side terminals of said voltage source type reversible AC-DC power converter units, respectively, and further comprising a magnetic core forming a magnetic path and a winding window in which said primary winding and secondary windings are disposed, and said secondary windings being separated in the direction of the magnetic path surrounded with said primary winding and secondary windings for increasing the leakage inductance between said secondary windings;
• wherein said voltage source type power converting apparatus converts the power between the multiple-phase AC system and the DC system by operating said voltage source type power converter units with phase differences in accordance with the phase differences between said secondary windings of said phase-shifting transformer or phase-shifting transformers, and a harmonic cross current between said voltage source type reversible AC-DC power converter units connected to said secondary windings disposed in said winding window is decreased by said leakage inductance between said secondary windings.