POWER CONVERSION DEVICE

摘要

PROBLEM TO BE SOLVED: To inexpensively and accurately detect on-operation malfunction (opening of a relay contact) of n relays.SOLUTION: A power conversion device comprises: a forward converter for rectifying AC voltage of an AC power supply to convert to DC voltage; a DC intermediate circuit having a smoothing capacitor for smoothing the DC voltage of the forward converter; a current-limiting circuit for suppressing charge current to the smoothing capacitor in the DC intermediate circuit; a voltage detection circuit for detecting voltage of the DC intermediate circuit; an inverse converter for converting the DC voltage of the forward converter to AC voltage; n temperature detection elements which are arranged on a circuit board connected to a terminal corresponding to contact parts of n relays connected in parallel to a resistance of the current-limiting circuit, and detect temperature of each of the n relays; and a control unit for detecting that any of the n relays is abnormal, on the basis of a detection result of each of the temperature detection elements. Detecting temperature differences among the n temperature detection elements makes it possible to detect abnormality of the relays.