LIFE DETERMINATION DEVICE FOR DC CAPACITOR CONNECTED TO DC SIDE OF RECTIFIER

摘要

A life determination device for a DC capacitor includes: a current detecting unit that detects a current outputted from a rectifier; a voltage detecting unit that detects a voltage of the DC capacitor; an initial charging device that performs initial charging of the DC capacitor up to a predetermined voltage value with the current outputted from the rectifier; a current integrating unit that integrates the current detected by the current detecting unit during a period of the initial charging; a capacitance estimating unit that calculates an estimated capacitance of the DC capacitor from the current integration value, the predetermined voltage value, and the voltage of the DC capacitor prior to the initial charging; and life determination unit that determines whether the DC capacitor is at the end of its life based on an initial capacitance value of the DC capacitor in an unused state and the estimated capacitance.

主权项

1. A life determination device for a DC capacitor connected to a DC side of a rectifier, the life determination device comprising:
a current detecting unit that detects a current outputted from the rectifier; a voltage detecting unit that detects a voltage applied to the DC capacitor; an initial charging unit that performs initial charging of the DC capacitor up to a predetermined voltage value with the current outputted from the rectifier; a current integrating unit that integrates, during a period of initial charging by the initial charging unit, the current detected by the current detecting unit and outputs the integrated current as a current integration value; a capacitance estimating unit that calculates an estimated capacitance of the DC capacitor from the current integration value, the predetermined voltage value and the voltage of the DC capacitor detected by the voltage detecting unit prior to the initial charging; and a life determination unit that determines whether the DC capacitor is at the end of its life based on a pre-measured initial capacitance value of the DC capacitor in an unused state and the estimated capacitance calculated by the capacitance estimating unit.