Method and apparatus for detecting the existence of a safety ground

• US 9,662,987 B2
• Filed: 01/03/2012
• Issued: 05/30/2017
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Lear Corporation
• Inventors: Hein, David A., Khalifeh, Ahmad
• Primary Examiner(s): Astacio-Oquendo, Giovanni
• Application Number:
  US13/342,294
• Publication Number:
  US 20120212235A1
• Time in Patent Office: 1,974 Days
• Field of Search: 324503, 324500, 324508, 324509, 324510, 324512, 324522
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: H02H 11/001 in case of incorrect or interrupted earth connection disconnection by breaking of earth connection H02H5/105
• CPC Class Codes: H02H 5/105 responsive to deterioration or interruption of earth connection for preventing switching-on H02H11/001
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

An apparatus including a test device for assessing the quality of a safety ground is provided. The test device is configured to receive an energy signal from a power source for charging a vehicle and to generate a first output signal in response to the first energy signal. The test device is further configured to measure a characteristic of the first output signal and to provide a test signal. The test device is further configured to generate a second output signal in response to providing the test signal and to measure a characteristic of the second output signal. The test device is further configured to assess the quality of a safety ground in at least one of the power source and the vehicle based on a difference between the characteristic of the first output signal and the characteristic of the second output signal.

Claims

1. An apparatus for assessing a quality of a safety ground, the apparatus comprising:

a test device including a filter and an amplifier circuit and being configured to;

receive an energy signal from a power source for charging a vehicle;

generate a first filtered output with the filter in response to the energy signal;

generate a first amplified filtered output with the amplifier circuit in response to the first filtered output;

measure a voltage of the first amplified filtered output;

provide a test signal after measuring the voltage of the first amplified filtered output;

generate a second filtered output with the filter in response to the test signal;

generate a second amplified filtered output with the amplifier circuit in response to the second filtered output;

measure a voltage of the second amplified filtered output; and

assess the quality of a safety ground in at least one of the power source and the vehicle based on the voltage of the first amplified filtered output, the voltage of the second amplified filtered output, and a threshold.

2. The apparatus of claim 1 wherein the test device is further configured to compare a difference between the voltage of the first amplified filtered output and the voltage of the second amplified filtered output to the threshold to assess the quality of the safety ground.

3. The apparatus of claim 2 wherein the test device is further configured to determine that the safety ground is faulty if the difference between the voltage of the first amplified filtered output and the voltage of the second amplified filtered output is greater than the threshold.

4. The apparatus of claim 2 wherein the test device is further configured to determine that the safety ground is acceptable if the difference between the voltage of the first amplified filtered output and the voltage of the second amplified filtered output is less than the threshold.

5. The apparatus of claim 1 wherein the test signal is an alternating current (AC) test signal.