Converter apparatus having function of detecting failure of power device, and method for detecting failure of power device

A converter apparatus comprising:

• a converter including a plurality of power devices, configured to convert an AC voltage supplied from a power supply into a DC voltage, and output the DC voltage;
• a DC link capacitor connected to an output side of the converter;
• a voltage detector configured to detect a voltage of the DC link capacitor;
• a charging circuit disposed between the converter and the DC link capacitor, configured to charge the DC link capacitor;
• a charging circuit controller configured to control a switch connected in parallel with a charging resistor in the charging circuit;
• a current detector configured to detect a current flowing between the converter and the DC link capacitor;
• a turn-on controller configured to control turning-on of the power devices of the converter;
• a switch configured to connect or disconnect between the power supply and the converter;
• a power supply monitor configured to control switching of the switch, and to monitor a connection state between the power supply and the converter by detecting a voltage to be inputted to the converter;
• a threshold value setter configured to set a first threshold value or a second threshold value to determine the presence or absence of a failure of the power devices;
• and
• a failure detector configured to determine the presence or absence of the failure of the power devices by a comparison between a current flowing upon turning on the power device of the converter using electric charge of the DC link capacitor, immediately after the switch disconnects the power supply from the converter and the switch is turned off, and the first threshold value or the second threshold value.