Power conversion device including a transformer with three or more windings

A power conversion device comprising:

• a transformer composed of three or more windings magnetically coupled with each other, the three or more windings including a first winding;
• a first switching circuit connected to the first winding;
• an AC/DC converter having a DC side connected to an input part of the first switching circuit, and converting input power from an AC power supply to DC;
• a first detector for detecting DC side voltage of the AC/DC converter;
• and
• a switching circuit and a load which are connected to at least one load side winding including at least one of the three or more windings besides the first winding, wherein
• the first switching circuit supplies AC power to the first winding at a predetermined time ratio, and the switching circuit connected to the at least one load side winding controls voltage on an output side of the AC/DC converter, based on a detected voltage value detected by the first detector and a target voltage value.