AC-to-DC power converter which removed a common mode component form the output current

A power conversion device which converts AC voltage from an AC power supply to DC voltage, further converts the DC voltage to desired DC voltage, and outputs the desired DC voltage to a DC load via a positive terminal and a negative terminal, the power conversion device comprising:

• a power conversion circuit which includes a plurality of first semiconductor switching elements connected in a bridge form, and which converts the AC voltage to DC voltage and outputs the DC voltage as DC link voltage;
• an AC filter capacitor unit connected between the AC power supply and the power conversion circuit, and having capacitors corresponding to respective phases of the AC voltage;
• a full-bridge chopper circuit including a plurality of second semiconductor switching elements connected so as to form a full-bridge circuit, the full-bridge chopper circuit having a positive leg and a negative leg respectively connected to the positive terminal and the negative terminal;
• a DC filter capacitor unit and a DC filter reactor unit connected between the full-bridge chopper circuit, and the positive terminal and the negative terminal;
• a neutral point line which connects a neutral point of the AC filter capacitor unit and a neutral point of the DC filter capacitor unit and through which a potential at the neutral point of the AC filter capacitor unit and a potential at the neutral point of the DC filter capacitor unit are made to be a common neutral point potential, the neutral point line not being connected to a ground point of which a potential is a ground potential;
• a controller for controlling the first semiconductor switching elements and the second semiconductor switching elements;
• and
• a current detector for detecting output current from the full-bridge chopper circuit, wherein
• the controller controls the plurality of second semiconductor switching elements on the basis of an output current command based on a predetermined value of output voltage, and a current detection value obtained by removing a common-mode component from the output current detected by the current detector, and
• the AC power supply includes a transformer of which a neutral point on an output side is grounded, and a potential of the neutral point line is equal to the ground potential.