# US 2013/0278272 A1 · Method and apparatus for high voltage isolation monitor for a vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0278272 A1 - Document ID: US20130278272A1 - Status: Published application - Kind: A1 - Application number: 13/449,665 - Filed: 2012-04-18 - Published: 2013-10-24 - Earliest claimed: 2012-04-18 - Assignees: Lear Corporation - Inventors: George Kaminski; Richard J. Hampo - Web page: https://patentgrep.com/patent/US20130278272A1 ## CPC - G01R 27/18: Measuring resistance to earth {, i.e. line to ground} - B60L 3/0069: {relating to the isolation, e.g. ground fault or leak current} - B60L 3/04: Cutting off the power supply under fault conditions (protective devices and circuit arrangements in general H01H; H02H) - G01R 31/006: {on road vehicles, e.g. automobiles or trucks (testing of ignition installations peculiar to internal combustion engines F02P17/00)} - G01R 31/52: Testing for short-circuits, leakage current or ground faults - G01R 31/14: Circuits therefor {, e.g. for generating test voltages, sensing circuits (G01R31/1209 - G01R31/1227 take precedence; for testing switches G01R31/327)} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 ## Abstract An apparatus for monitoring a high voltage isolation in a vehicle. The apparatus comprising a power conversion device for receiving a high voltage on a power bus. The power conversion device is configured to control a first switch for enabling a first known resistance to receive the high voltage and to measure a first voltage between a first node and a ground in response to the first known resistance receiving the high voltage. The power conversion device is further configured to measure a second voltage between a second node and the ground in response to the first known resistance receiving the high voltage and to determine a first leakage resistance between the first node and the ground based on at least the first voltage and the second voltage. The first leakage resistance indicating whether the high voltage is isolated from the ground. ## Claims ### Claim 1 An apparatus for monitoring a high voltage isolation in a vehicle, the apparatus comprising: a power conversion device for receiving a high voltage on a power bus, the power bus including a first node and a second node, the power conversion device being configured to: control a first switch for enabling a first known resistance to receive the high voltage; measure a first voltage between the first node and a ground in response to the first known resistance receiving the high voltage; measure a second voltage between the second node and the ground in response to the first known resistance receiving the high voltage; and determine a first leakage resistance between the first node and the ground based on at least the first voltage and the second voltage, the first leakage resistance being indicative of whether the high voltage is isolated from the ground. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein the power conversion device is further configured to control a second switch for enabling a second known resistance to receive the high voltage and to measure a third voltage between the first node and the ground in response to the third known resistance receiving the high voltage. ### Claim 3 (depends on 2) The apparatus of claim 2 wherein the power conversion device is further configured to measure a fourth voltage between the second node and the ground in response to the second known resistance receiving the high voltage. ### Claim 4 (depends on 3) The apparatus of claim 3 wherein the power conversion device is further configured to determine a second leakage resistance between the second node and the ground based on at least the third voltage and the fourth voltage, the second leakage resistance also being indicative of whether the high voltage is isolated from the ground. ### Claim 5 (depends on 1) The apparatus of claim 1 wherein the first node of the power bus comprises a positive high voltage node. ### Claim 6 (depends on 1) The apparatus of claim 1 wherein the second node of the power bus comprises a negative high voltage node. ### Claim 7 (depends on 1) The apparatus of claim 1 wherein the ground is a chassis ground positioned in the vehicle. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein the power conversion device includes a switching device for enabling the high voltage to pass there through when the power conversion device is in a normal operating mode and for preventing a voltage to pass there through when the power conversion device is being exposed to a hi-pot test. ### Claim 9 (depends on 1) The apparatus of claim 1 wherein the power conversion device is further configured to initiate a timer prior to measuring the first voltage and the second voltage. ### Claim 10 A method for monitoring a high voltage isolation in a vehicle, the method comprising: receiving a high voltage on a power bus, the power bus including a first node and a second node controlling a first switch for enabling a first known resistance to receive the high voltage; measuring a first voltage between the first node and a ground in response to the first known resistance receiving the high voltage; measuring a second voltage between the second node and the ground in response to the first known resistance receiving the high voltage; and determining a first leakage resistance between the first node and the ground based on at least the first voltage and the second voltage, the first leakage resistance being indicative of whether the high voltage is isolated from the ground. ### Claim 11 (depends on 10) The method of claim 10 further comprising controlling a second switch for enabling a second known resistance to receive the high voltage and measuring a third voltage between the first node and the ground in response to the third known resistance receiving the high voltage. ### Claim 12 (depends on 11) The method of claim 11 further comprising measuring a fourth voltage between the second node and the ground in response to the second known resistance receiving the high voltage. ### Claim 13 (depends on 12) The method of claim 12 further comprising determining a second leakage resistance between the second node and the ground based on at least the third voltage and the fourth voltage, the second leakage resistance also being indicative of whether the high voltage is isolated from the ground. ### Claim 14 (depends on 10) The method of claim 10 wherein the first node of the power bus comprises a positive high voltage node. ### Claim 15 (depends on 10) The method of claim 10 wherein the second node of the power bus comprises a negative high voltage node. ### Claim 16 (depends on 10) The method of claim 10 wherein the ground is a chassis ground positioned in the vehicle. ### Claim 17 (depends on 10) The method of claim 10 further comprising: enabling, with a switching device, the high voltage to pass through a power conversion device in a normal operating mode; and preventing, with the switching device, a voltage to pass through the power conversion device when the power conversion device is being exposed to a hi-pot test. ### Claim 18 (depends on 10) The method of claim 10 further comprising initiating a timer prior to measuring the first voltage and the second voltage. ### Claim 19 An apparatus for monitoring a high voltage isolation in a vehicle, the apparatus comprising: a power conversion device for receiving a high voltage on a power bus, the power bus including a positive node and a negative node, the power conversion device being configured to: control a first switch for enabling a first known resistance to receive the high voltage; determine a first voltage between the positive node and a ground in response to the first known resistance receiving the high voltage; determine a second voltage between the negative node and the ground in response to the first known resistance receiving the high voltage; and determine a first leakage resistance between the positive node and the ground based on at least the first voltage and the second voltage, the first leakage resistance being indicative of whether the high voltage is isolated from the ground. ### Claim 20 (depends on 19) The apparatus of claim 19 wherein the power conversion device includes a switching device for enabling the high voltage to pass there through when the vehicle is running and for preventing a voltage to pass there through when the power conversion device is being exposed to a hi-pot test.