Power conversion device

A power conversion device comprising:

• a power converter including an arm configured with one unit converter or a plurality of unit converters connected in series;
• and
• a control device configured to control the power converter,
• the unit converter including
• a main circuit including a switching element and a DC capacitor and configured to output a voltage pulse according to voltage of the DC capacitor by turning on/off of the switching element,
• a control circuit configured to control on/off of the switching element in accordance with a control signal received from the control device, and
• a power supply configured to lower voltage of the DC capacitor to generate power supply voltage to be supplied to the control circuit,
• the power supply including
• a power supply circuit configured to convert input voltage provided between first and second input terminals from the DC capacitor into the power supply voltage,
• a thyristor connected between the first and second input terminals electrically in parallel with the power supply circuit,
• a current-limiting resistor connected between terminals of the DC capacitor electrically in series with the thyristor, and
• a control unit configured to fire the thyristor when the input voltage applied to the power supply circuit exceeds a threshold voltage.