POWER CONVERSION DEVICE, MOTOR DRIVE DEVICE COMPRISING SAME, VENTILATOR COMPRISING SAME, COMPRESSOR, AND AIR CONDITIONER, REFRIGERATOR, AND FREEZER COMPRISING THESE

摘要

The purpose of the present invention is to provide a power conversion device capable of: increasing the overcurrent detection period for a phase current; simplifying an overcurrent detection procedure; and improving the operation reliability of an inverter or load device. The power conversion device has provided therein: a power supply shunt resistance (5) provided between an inverter (2) and the negative voltage side of a DC power supply (1); and phase lower arm shunt resistance (6a-6c) each provided between each phase lower arm switching element (3d-3f) and the power supply shunt resistance (5). The power conversion device comprises: a first overcurrent detection unit (21a) that detects overcurrent in current that flows to the power supply shunt resistance (5), on the basis of power supply shunt resistance voltage (Vx); and a second overcurrent detection unit (21b) that detects overcurrent in each current that flows to each phase lower arm shunt resistance (6a-6c), on the basis of each phase lower arm voltage (Vu, Vv, Vw). The power conversion device is configured so as to detect overcurrent in each phase current, using either the overcurrent detection results from the first overcurrent detection unit (21a) or the overcurrent detection results from the second overcurrent detection unit (21b).