Power conversion apparatus, deterioration determination method for smoothing capacitor

A power conversion apparatus, comprising:

• a power conversion unit that converts DC power to AC power and outputs the AC power;
• a smoothing capacitor that smoothens the DC power;
• a capacitance acquiring unit that acquires a capacitance value of the smoothing capacitor;
• and
• a deterioration determining unit that determines a deterioration state of the smoothing capacitor, wherein
• the capacitance acquiring unit acquires a plurality of initial capacitance values indicating capacitance values of the smoothing capacitor in an initial state in accordance with a change in an operation state of the power conversion unit and acquires a plurality of operation capacitance values indicating capacitance values of the smoothing capacitor in the operation state;
• and
• the deterioration determining unit:
• acquires characteristic information indicating a relationship between the AC power and the capacitance value of the smoothing capacitor in the initial state on the basis of a statistic amount of the plurality of initial capacitance values acquired by the capacitance acquiring unit, wherein the smoothing capacitor is in an initial state when a predetermined initial operation period has not elapsed or the acquisition of the characteristic information of the smoothing capacitor has not been finished, and wherein a statistic amount of the initial capacitance values is an average value, a median value, a standard deviation, an upper fence, and a lower fence thereof;
• and
• determines a deterioration state of the smoothing capacitor on the basis of a statistic amount of the plurality of operation capacitance values acquired by the capacitance acquiring unit and the characteristic information.