# US 11,897,343 B2 · Earth leakage detecting device, and vehicular power supply system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,897,343 B2 - Document ID: US11897343B2 - Status: Granted - Kind: B2 - Application number: 17/621,183 - Filed: 2020-06-15 - Published: 2022-11-10 - Granted: 2024-02-13 - Earliest claimed: 2019-06-28 - Assignees: Sanyo Electric Co., Ltd. - Applicants: SANYO Electric Co., Ltd. - Inventors: Masato Nakayama - Web page: https://patentgrep.com/patent/US11897343B2 ## CPC - B60L 3/0069: {relating to the isolation, e.g. ground fault or leak current} - B60L 3/0046: {relating to electric energy storage systems, e.g. batteries or capacitors} - B60L 3/12: Recording operating variables {; Monitoring of operating variables} - G01R 31/52: Testing for short-circuits, leakage current or ground faults - H02H 3/17: by means of an auxiliary voltage injected into the installation to be protected {(using summation current transformers H02H3/33)} - G01R 31/006: {on road vehicles, e.g. automobiles or trucks (testing of ignition installations peculiar to internal combustion engines F02P17/00)} - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In earth leakage detection device, one end of coupling capacitor is connected to a current path of power storage unit connected to load in a state of being insulated from the ground. Voltage output unit generates a periodically changing periodic voltage, and applies the periodic voltage to the other end of coupling capacitor via first resistor. Second resistor and third resistor are connected in series between a node between coupling capacitor and first resistor and a predetermined fixed potential. Voltage measurement unit measures a voltage at a voltage dividing point between second resistor and third resistor. Earth leakage determination unit determines presence or absence of an earth leakage between the current path of power storage unit and the ground based on the measured voltage. ## Claims ### Claim 1 An earth leakage detection device, comprising: a coupling capacitor including one end connected to a current path of a power storage unit, the power storage unit being connected to a load in a state of being insulated from a ground; a voltage output unit that generates a periodically changing periodic voltage and applies the periodically changing periodic voltage to another end of the coupling capacitor via a first resistor; a second resistor and a third resistor connected in series between (i) a node between the coupling capacitor and the first resistor and (ii) a predetermined fixed potential; a voltage measurement unit that measures a voltage at a voltage dividing point between the second resistor and the third resistor; and an earth leakage determination unit that determines whether or not a leakage occurs between the current path of the power storage unit and the ground based on the voltage measured by the voltage measurement unit. ### Claim 2 (depends on 1) The earth leakage detection device according to claim 1, wherein the fixed potential is set to an intermediate potential of a measurement range of the voltage measurement unit, and a voltage dividing ratio between the second resistor and the third resistor is set according to a ratio between a measurement range of the voltage measurement unit and a voltage range to be detected. ### Claim 3 (depends on 1) The earth leakage detection device according to claim 1, further comprising a switch connected between the third resistor and the fixed potential, wherein the earth leakage determination unit turns off the switch when an entire amplitude of the voltage restored according to the voltage dividing ratio between the second resistor and the third resistor falls within the measurement range of the voltage measurement unit in an on state of the switch. ### Claim 4 (depends on 1) The earth leakage detection device according to claim 1, wherein the earth leakage detection device includes a terminal of the third resistor configured to be applied a first fixed potential and a second fixed potential, the first fixed potential being set to an upper limit potential of a measurement range of the voltage measurement unit, and the second fixed potential being set to a lower limit potential, the terminal of the third resister not being connected to the second resistor, and the earth leakage determination unit applies the second fixed potential to the terminal when a measured voltage sticks to an upper limit of the measurement range, and applies the first fixed potential to the terminal when the measured voltage sticks to a lower limit of the measurement range. ### Claim 5 (depends on 1) A vehicular power supply system, comprising: the earth leakage detecting device according to claim 1; and a power storage unit that is mounted in a vehicle in a state of being insulated from a chassis ground of the vehicle and supplies power to a load in the vehicle.