A power conversion device for converting DC voltage inputted from a DC power supply, to three-phase AC voltage, the power conversion device comprising: a first single-phase conversion device configured to convert the DC voltage inputted from the DC power supply, to voltage having an AC waveform to be outputted to a first phase with respect to a neutral point of three-phase AC; a second single-phase conversion device configured to convert the DC voltage inputted from the DC power supply, to voltage having an AC waveform to be outputted to a second phase with respect to the neutral point; a third single-phase conversion device configured to convert the DC voltage inputted from the DC power supply, to voltage having an AC waveform to be outputted to a third phase with respect to the neutral point; and a control unit configured to control the first-phase conversion device, the second-phase conversion device, and the third-phase conversion device, characterized in that: each of the first single-phase conversion device, the second single-phase conversion device, and the third single-phase conversion device includes: a first conversion unit having a DC/DC converter including an isolation transformer, and a smoothing capacitor, the first conversion unit being configured to, by the control unit controlling the DC/DC converter, convert the inputted DC voltage to a first voltage waveform containing a waveform corresponding to an absolute value of voltage obtained by superimposing a third-order harmonic on a fundamental wave of every half cycle of the AC waveform; and a second conversion unit provided at a stage subsequent to the first conversion unit and having a full-bridge inverter, the second conversion unit being configured to, by the control unit controlling the full-bridge inverter, convert the first voltage waveform to a second voltage waveform having the AC waveform, wherein only during a period in which the voltage outputted from the first conversion unit has a value that is equal to or lower than a predetermined proportion of a wave crest value of the first voltage waveform, the control unit causes the full-bridge inverter to perform inverter operation at a high switching frequency, thereby generating voltage having the AC waveform including a zero cross of the AC waveform in the period. a first single-phase conversion device configured to convert the DC voltage inputted from the DC power supply, to voltage having an AC waveform to be outputted to a first phase with respect to a neutral point of three-phase AC; a second single-phase conversion device configured to convert the DC voltage inputted from the DC power supply, to voltage having an AC waveform to be outputted to a second phase with respect to the neutral point; a third single-phase conversion device configured to convert the DC voltage inputted from the DC power supply, to voltage having an AC waveform to be outputted to a third phase with respect to the neutral point; and a control unit configured to control the first-phase conversion device, the second-phase conversion device, and the third-phase conversion device, characterized in that: each of the first single-phase conversion device, the second single-phase conversion device, and the third single-phase conversion device includes: a first conversion unit having a DC/DC converter including an isolation transformer, and a smoothing capacitor, the first conversion unit being configured to, by the control unit controlling the DC/DC converter, convert the inputted DC voltage to a first voltage waveform containing a waveform corresponding to an absolute value of voltage obtained by superimposing a third-order harmonic on a fundamental wave of every half cycle of the AC waveform; and a second conversion unit provided at a stage subsequent to the first conversion unit and having a full-bridge inverter, the second conversion unit being configured to, by the control unit controlling the full-bridge inverter, convert the first voltage waveform to a second voltage waveform having the AC waveform, wherein only during a period in which the voltage outputted from the first conversion unit has a value that is equal to or lower than a predetermined proportion of a wave crest value of the first voltage waveform, the control unit causes the full-bridge inverter to perform inverter operation at a high switching frequency, thereby generating voltage having the AC waveform including a zero cross of the AC waveform in the period. a first conversion unit having a DC/DC converter including an isolation transformer, and a smoothing capacitor, the first conversion unit being configured to, by the control unit controlling the DC/DC converter, convert the inputted DC voltage to a first voltage waveform containing a waveform corresponding to an absolute value of voltage obtained by superimposing a third-order harmonic on a fundamental wave of every half cycle of the AC waveform; and a second conversion unit provided at a stage subsequent to the first conversion unit and having a full-bridge inverter, the second conversion unit being configured to, by the control unit controlling the full-bridge inverter, convert the first voltage waveform to a second voltage waveform having the AC waveform, wherein only during a period in which the voltage outputted from the first conversion unit has a value that is equal to or lower than a predetermined proportion of a wave crest value of the first voltage waveform, the control unit causes the full-bridge inverter to perform inverter operation at a high switching frequency, thereby generating voltage having the AC waveform including a zero cross of the AC waveform in the period.