Patent ID: 9595887
Date: 2017-03-14
CPC Classifications: H02M

Claim:
1. A three-phase power conversion device comprising: single-phase inverters each including a DC capacitor and a plurality of semiconductor switching elements, the single-phase inverters having AC output ends connected in series to respective phases of three-phase AC lines; and a control device for performing PWM control for each single-phase inverter based on a voltage command, the three-phase power conversion device further comprising an AC voltage detection circuit for detecting a phase and voltage of three-phase AC voltage from the three-phase AC lines, wherein the control device includes a voltage command generating section for, based on the phase and the voltage from the AC voltage detection circuit, adding a zero-phase component common to the three phases to a basic command for each phase to generate the voltage command, and the voltage command generating section determines an amplitude of the zero-phase component so that a magnitude of a peak of the voltage command becomes smaller than a maximum absolute value of the basic command for each phase, and applies the amplitude to reference zero-phase voltage set in advance, to determine the zero-phase component synchronized with the phase of the three-phase AC voltage.