Deterioration detecting apparatus and deterioration detecting method

1. A deterioration detecting apparatus comprising:

a capacitor that is connected to an insulated electric power source, and is charged and discharged;

a voltage detecting unit that detects a voltage of the capacitor; and

a deterioration detecting unit that detects a deterioration in an insulating resistor of the electric power source on the basis of the voltage of the capacitor charged through a charging path for detecting the deterioration in the insulating resistor of the electric power source, and the voltage of the capacitor during discharging, wherein the deterioration detecting unit:

includes a discharge rate calculating unit that calculates a discharge rate of the capacitor on the basis of the voltage of the capacitor charged, and the voltage of the capacitor discharged for a predetermined time after charging of the capacitor;

detects the deterioration in the insulating resistor of the electric power source on the basis of the voltage of the charged capacitor and the discharge rate; and

in a case where the voltage of the charged capacitor is equal to or greater than a predetermined threshold value, and the discharge rate is within a predetermined range, the deterioration detecting unit detects the deterioration in the insulating resistor of the electric power source.

2. The deterioration detecting apparatus according to claim 1 , wherein:

in a case where the voltage of the charged capacitor is less than a predetermined threshold value, and the discharge rate is out of the predetermined range, the deterioration detecting unit detects a deterioration in elements including the capacitor positioned on a discharging path, and determines that there is no deterioration in the insulating resistor of the electric power source.

3. The deterioration detecting apparatus according to claim 1 , wherein:

in a case where the voltage of the charged capacitor is equal to or greater than a predetermined threshold value, and the discharge rate is out of a predetermined range, the deterioration detecting unit:

corrects the voltage of the capacitor detected by the voltage detecting unit, or the threshold value, and

uses the corrected capacitor voltage or the corrected threshold value to detect the deterioration in the insulating resistor of the electric power source.

4. A deterioration detecting apparatus comprising:

a capacitor that is connected to an insulated electric power source, and is charged and discharged;

a voltage detecting unit that detects a voltage of the capacitor; and

a deterioration detecting unit that detects a deterioration in an insulating resistor of the electric power source on the basis of the voltage of the capacitor charged through a charging path for detecting the deterioration in the insulating resistor of the electric power source, and the voltage of the capacitor during discharging, wherein the deterioration detecting unit:

includes a discharge rate calculating unit that calculates a discharge rate of the capacitor on the basis of the voltage of the capacitor charged, and the voltage of the capacitor discharged for a predetermined time after charging of the capacitor;

detects the deterioration in the insulating resistor of the electric power source on the basis of the voltage of the charged capacitor and the discharge rate; and

in a case where the voltage of the charged capacitor is equal to or greater than a predetermined threshold value, and the discharge rate is out of a predetermined range, the deterioration detecting unit:

corrects the voltage of the capacitor detected by the voltage detecting unit, or the threshold value, and

uses the corrected capacitor voltage or the corrected threshold value to detect the deterioration in the insulating resistor of the electric power source.

5. A deterioration detecting method comprising:

detecting a voltage of a capacitor which is connected to an insulated electric power source and is charged and discharged;

calculating a discharge rate of the capacitor on the basis of the voltage of the capacitor charged, and the voltage of the capacitor discharged for a predetermined time after charging of the capacitor; and

detecting a deterioration in an insulating resistor of the electric power source on the basis of the voltage of the capacitor charged through a charging path for detecting the deterioration in the insulating resistor of the electric power source, and the voltage of the capacitor during discharging, wherein

in the detecting, the deterioration in the insulating resistor of the electric power source is detected on the basis of the voltage of the charged capacitor and the discharge rate, and

in a case where the voltage of the charged capacitor is equal to or greater than a predetermined threshold value, and the discharge rate is within a predetermined range, the deterioration in the insulating resistor of the electric power source is detected in the detecting.