POWER CONVERSION DEVICE

A power conversion device enabling a downsizing of a charging unit is provided. The power conversion device includes, in each phase, a positive side phase arm including unit converters connected to a DC positive side terminal and connected in multi stage, each unit converter including a switching element and a capacitor, a negative side phase arm including unit converters connected to a DC negative side terminal and connected in multi stage, each unit converter including a switching element and a capacitor, a three-winding transformer connected between the positive side phase arm and the negative side phase arm, and a plurality of charging units each including a charging resistor and a disconnection switch connected in parallel with each other. The three-winding transformer includes a secondary winding connected to the positive side phase arm and a tertiary winding connected to the negative side phase arm, and a negative side of the secondary winding and a negative side of the tertiary winding are connected with each other in each phase and among three phases. The charging units are connected between the positive side phase arm and the secondary winding, and between the negative side phase arm and the tertiary winding, respectively.