Power conversion device

A power conversion device comprising a plurality of cell converters connected in series to each other,

• each cell converter having:
• a main circuit including switching elements and a capacitor;
• a pair of external terminals for leading the main circuit to outside;
• a bypass unit capable of making short circuit between the pair of external terminals;
• a gate drive device for performing ON/OFF control of the switching elements, thereby for performing power conversion between the pair of external terminals and the capacitor;
• and a self-power-feeding device for receiving voltage of the capacitor and for feeding power to the gate drive device, the power conversion device comprising:
• an energy storage unit for receiving and storing voltage of the self-power-feeding device;
• and
• a bypass unit drive device for causing the bypass unit to perform short-circuiting operation by power stored in the energy storage unit when voltage of the self-power-feeding device becomes smaller than a predetermined lower limit value.