Power conversion device

A power conversion device that converts direct current power into alternating current power for a load, and supplies the alternating current power to the load, the power conversion device comprising:

• a three-phase three-level inverter connected between positive and negative terminals of a direct current power supply;
• three single-phase inverters respectively connected between the load and alternating current terminals of respective phases different from one another, of the three-phase three-level inverter;
• and
• a controller to generate gate signals for controlling operation of the three-phase three-level inverter and of the three single-phase inverters, based on sinusoidal phase voltage commands, wherein
• the controller
• divides the sinusoidal phase voltage commands into three-phase instantaneous voltage commands to be indicated to the three-phase three-level inverter and mean voltage commands to be indicated to the respective three single-phase inverters, and
• in a case in which a sum of the three-phase instantaneous voltage commands is a positive value, superimposes a common voltage component on each of the three mean voltage commands to make a sum of the three mean voltage commands a non-positive value, or
• in a case in which the sum of the three-phase instantaneous voltage commands is a negative value, superimposes the common voltage component on each of the three mean voltage commands to make the sum of the three mean voltage commands a non-negative value.