Electrical leakage determination system

Patent metadata

Field	Value
Publication number	US-2020116775-A1
Application number	US-201916654222-A
Country	US
Kind code	A1
Filing date	Oct 16, 2019
Priority date	Oct 16, 2018
Publication date	Apr 16, 2020
Grant date	—

Abstract

An electrical leakage determination system determines if an electrical leakage occurs between each of power supply paths and a grounding section. The electrical leakage determination system includes a coupling capacitor with one end connected to an anode-side power supply path, a resistor connected to the other end of the coupling capacitor, and an oscillator connected to the resistor to output an AC voltage to the resistor. A determiner detects a voltage at a connection point located between the coupling capacitor and the resistor when the oscillator outputs an AC voltage to the resistor. The determiner determines if the electrical leakage occurs based on the detected voltage. The oscillator increases an absolute value of an AC voltage output during a preparation period provided prior to a detection timing when a voltage is detected at a connection point greater than an absolute value of an AC voltage output at the detection timing.

First claim

1 . An electrical leakage determination system to determine if an electrical leakage occurs between a power supply path connected to a power supply terminal of a DC power supply and a grounding section, the electrical leakage determination system comprising:
a coupling capacitor connected to the power supply path at its one end; a resistor connected to the other end of the coupling capacitor; an oscillator connected to the resistor to output an AC voltage to the resistor; and a determiner to detect a voltage generated at a connection point located between the coupling capacitor and the resistor at a detection timing when the oscillator outputs an AC voltage to the resistor, the determiner determining if the electrical leakage occurs based on the detected voltage, wherein the oscillator outputs the AC voltage having a first absolute value in a preparation period provided before detecting the voltage generated at the connection point at the detection timing, the first absolute value greater than a second absolute value of the AC voltage output when the determiner detects the voltage generated at the connection point at the detection timing.

2 . The electrical leakage determination system according to claim 1 , wherein the oscillator maintains a polarity of the AC voltage from when the preparation period starts until the end of the detection timing.

3 . The electrical leakage determination system according to claim 1 , wherein the determiner detects the voltage generated at the connection point when a given period has elapsed after the end of the preparation period.

4 . The electrical leakage determination system according to claim 1 , further comprising a filter to filter out at least an excessive absolute value from the AC voltage output during the preparation period,
wherein the determiner determines if the electrical leakage occurs based on the detected voltage input to the determiner via the filter.

5 . The electrical leakage determination system according to claim 1 , wherein the oscillator makes a voltage having a first rectangular wave and a voltage having a second rectangular wave to overlap each other and outputs an overlapping result during the preparation period,
the oscillator outputting only the voltage of the second rectangular wave from a time when the preparation period has elapsed until the end of the detection timing.

6 . The electrical leakage determination system according to claim 1 , wherein the oscillator includes a first AC power supply to output a voltage having a first rectangular wave and a second AC power supply to output a voltage having a second rectangular wave,
wherein the oscillator makes a voltage having a first rectangular wave and a voltage having a second rectangular wave overlap each other and outputs an overlapping result during the preparation period, the oscillator outputting only the voltage of the second rectangular wave from a time when the preparation period has elapsed until the end of the detection timing.

7 . The electrical leakage determination system according to claim 1 , wherein the oscillator outputs an AC voltage having a saw wave, the saw wave having a peak of an absolute voltage value at the start of the preparation period and a portion in which the absolute voltage value gradually decreases subsequent to the peak per cycle of the saw wave.

8 . The electrical leakage determination system according to claim 1 , wherein the absolute value of the AC voltage output during the preparation period is changeable.

9 . The electrical leakage determination system according to claim 5 , further comprising a setter to set at least two different types of the first rectangular wave,
wherein the oscillator makes a voltage having the first rectangular wave of the type set by the setter and the voltage having the second rectangular wave overlap each other, the oscillator outputting an overlapping result during the preparation period, wherein the determiner detects at least two voltages generated at the connection point-based on the at least two different types of the first rectangular wave, the determiner determining if the electrical leakage occurs based on the types of the first rectangular wave and the at least two voltages detected at the connection point when the respective types of the first rectangular wave are output.

10 . The electrical leakage determination system according to claim 9 , wherein the determiner specifies a ground fault resistance that allows the at least two voltages detected at the connection point to satisfy the following first to third equations, the determiner determining if the electrical leakage occurs based on the ground fault resistance specified,
wherein V 1 represents a voltage of the first rectangular wave, V 2 represents a voltage of the second rectangular wave, Rg represents a value of the ground fault resistance, Cg represents a value of the ground capacitance, td represents a period from when application of AC voltage starts until a detection timing and tp represents a period from when application of AC voltage starts until a preparation period ends and Vrd(td) represents a voltage detected at a connection point.

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Assignees

• Denso Corp

Inventors

• Wakimoto Toru
• Shindo Yusuke
• Kouda Masakazu

Classifications

• G01R31/42

  AC power supplies · CPC title

• G01R31/50 Primary

  Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections (testing of sparking plugs H01T13/58) · CPC title

• G01R31/025 Primary

  Physics · mapped topic

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title

• G01R31/40

  Testing power supplies (testing photovoltaic devices H02S50/10) · CPC title