Insulation detecting device and insulation detecting method of non-grounded power supply
First Claim
1. An insulation detecting device which includes a flying capacitor configured to retain a charged voltage and a measurement circuit configured to measure the charged voltage of the flying capacitor, is connected to a direct-current power supply electrically insulated from a ground, and measures a ground fault resistance formed between the direct-current power supply and the ground based on the charged voltage of the flying capacitor which is measured by the measurement circuit, the insulation detecting device comprising:
- a plurality of switches configured to switch a first path from a positive electrode of the direct-current power supply to an negative electrode of the direct-current power supply through the flying capacitor, a second path from the positive electrode of the direct-current power supply to the ground through the flying capacitor, a third path from the ground to the negative electrode of the direct-current power supply through the flying capacitor, and a fourth path which releases a connection between the flying capacitor and the direct-current power supply and connects the flying capacitor and the measurement circuit;
a control unit configured to monitor a measurement voltage of the flying capacitor charged through the second path, and in a case where the measurement voltage is about 0 V (zero volt), control a switching of the switches, control a charging of the flying capacitor through the third path and a measuring of the charged voltage of the flying capacitor charged through the third path, and measure a first measurement voltage in a first time after the switching to the third path and a second measurement voltage in a second time different from the first time; and
a calculating unit configured to calculate the ground fault resistance formed between the direct-current power supply and the ground based on the first measurement voltage and the second measurement voltage.
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Accused Products
Abstract
An insulation detecting device includes a control unit configured to monitor a measurement voltage of a flying capacitor charged through a second path, and in a case where a measurement voltage is about 0 V (zero volt), control a switching of switches, control a charging of the flying capacitor through a third path and a measuring of a charged voltage of the flying capacitor charged through the third path, and measure a first measurement voltage in a first time after the switching to the third path and a second measurement voltage in a second time different from the first time, and a calculating unit configured to calculate a ground fault resistance formed between a direct-current power supply and a ground based on the first measurement voltage and the second measurement voltage.
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Citations
7 Claims
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1. An insulation detecting device which includes a flying capacitor configured to retain a charged voltage and a measurement circuit configured to measure the charged voltage of the flying capacitor, is connected to a direct-current power supply electrically insulated from a ground, and measures a ground fault resistance formed between the direct-current power supply and the ground based on the charged voltage of the flying capacitor which is measured by the measurement circuit, the insulation detecting device comprising:
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a plurality of switches configured to switch a first path from a positive electrode of the direct-current power supply to an negative electrode of the direct-current power supply through the flying capacitor, a second path from the positive electrode of the direct-current power supply to the ground through the flying capacitor, a third path from the ground to the negative electrode of the direct-current power supply through the flying capacitor, and a fourth path which releases a connection between the flying capacitor and the direct-current power supply and connects the flying capacitor and the measurement circuit; a control unit configured to monitor a measurement voltage of the flying capacitor charged through the second path, and in a case where the measurement voltage is about 0 V (zero volt), control a switching of the switches, control a charging of the flying capacitor through the third path and a measuring of the charged voltage of the flying capacitor charged through the third path, and measure a first measurement voltage in a first time after the switching to the third path and a second measurement voltage in a second time different from the first time; and a calculating unit configured to calculate the ground fault resistance formed between the direct-current power supply and the ground based on the first measurement voltage and the second measurement voltage. - View Dependent Claims (2, 3)
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4. An insulation detecting device which includes a flying capacitor configured to retain a charged voltage and a measurement circuit configured to measure the charged voltage of the flying capacitor, is connected to a direct-current power supply electrically insulated from a ground and to a voltage boosting circuit on a side of the direct-current power supply, and measure a ground fault resistance formed between the direct-current power supply and a secondary side of the voltage boosting circuit, and the ground, the voltage boosting circuit being configured to boost an output voltage of the direct-current power supply and electrically insulated from the ground, the insulation detecting device comprising:
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a plurality of switches configured to switch a first path from a positive electrode of the direct-current power supply to an negative electrode of the direct-current power supply through the flying capacitor, a second path from the positive electrode of the direct-current power supply to the ground through the flying capacitor, a third path from the ground to the negative electrode of the direct-current power supply through the flying capacitor, and a fourth path which releases a connection between the flying capacitor and the direct-current power supply and connects the flying capacitor and the measurement circuit; a control unit configured to, in a case where an output voltage on the secondary side is boosted by a boosting operation of the voltage boosting circuit and the ground potential becomes higher than a potential on the positive electrode side of the direct-current power supply, control a switching of the switches, control a charging of the flying capacitor through the third path and a measuring of the charged voltage of the flying capacitor charged through the third path, and measure a first measurement voltage in a first time after the switching to the third path and a second measurement voltage in a second time different from the first time; and a calculating unit configured to calculate the ground fault resistance formed between the direct-current power supply and the secondary side of the voltage boosting circuit, and the ground based on the first measurement voltage and the second measurement voltage. - View Dependent Claims (5, 6)
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7. An insulation detecting method of measuring a ground fault resistance which is formed between a direct-current power supply electrically insulated from a ground and the ground, the insulation detecting method comprising the steps of:
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connecting a flying capacitor between a positive electrode of the direct-current power supply and the ground to charge the flying capacitor; connecting a measurement circuit to the flying capacitor after the positive electrode of the direct-current power supply is disconnected from the flying capacitor, and measuring a voltage charged in the flying capacitor; monitoring the measured voltage, and in a case where the measured voltage is about 0 V (zero volt), charging the flying capacitor by connecting the flying capacitor between the ground and an negative electrode of the direct-current power supply, and measuring a first measurement voltage in a first time after the connection of the flying capacitor and a second measurement voltage in a second time different from the first time; and calculating the ground fault resistance formed between the direct-current power supply and the ground based on the first measurement voltage and the second measurement voltage.
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Specification