Patent ID: 8279639

Claim:
A direct AC power converting apparatus, comprising: a plurality of input lines to which an output of a multi-phase AC power supply including a neutral point is applied; a positive-side DC power supply line; a negative-side DC power supply line to which a potential lower than a potential applied to said positive-side DC power supply line is applied; a current-source power converter including a plurality of switch devices, converting a multi-phase AC voltage applied between ones of said plurality of input lines into a square-wave-shape DC voltage having two potentials by selection operations of said plurality of switch devices, and supplying said DC voltage between said positive-side DC power supply line and said negative-side DC power supply line; a plurality of input capacitors each provided between the ones of said plurality of input lines and functioning as a voltage source; a first diode provided between said positive-side DC power supply line and said negative-side DC power supply line and having an anode on said positive-side DC power supply line and a cathode on said negative-side DC power supply line side; first and second capacitors connected, between said positive-side DC power supply line and said negative-side DC power supply line, in series with said first diode; a neutral phase input line connecting said neutral point and a point between said first capacitor and said second capacitor; a voltage-source power converter converting said DC voltage into a square-wave-shape AC voltage and outputting to an inductive multi-phase load; a resistor inserted in any one of said plurality of input lines and said neutral phase input line; and a control section controlling the selection operations of said plurality of switch devices, performing voltage doubler rectification on a phase voltage for one phase which is applied between one of said plurality of input lines and said neutral phase input line, and supplying for charging of said first capacitor and said second capacitor through said resistor.