Patent ID: 8154893

Claim:
A three-phase power converting apparatus for connecting a DC power supply to a three-phase power system, said three-phase power converting apparatus comprising: a smoothing capacitor connected between positive and negative terminals of the DC power supply; a three-phase inverter circuit for converting DC power fed from said smoothing capacitor into three-phase AC power; and single-phase inverters which are connected in series with AC output lines of individual phases of said three-phase inverter circuit; said three-phase power converting apparatus being characterized in that said three-phase inverter circuit outputs a few reverse-polarity voltage pulses or less in a specific region within each of basic voltage pulses of which a pulse frequency corresponds to that of a system voltage, and said individual single-phase inverters output voltages by PWM control operation in such a manner as to make up for differences between phase voltages of the power system and outputs of said respective three-phase inverter circuit, and correct the outputs of said three-phase inverter circuit by subtracting a common voltage from target output voltages of the individual phases set in the PWM control operation during periods when said three-phase inverter circuit generates the reverse-polarity voltage pulses.