Method and apparatus to detect leakage current between power sources
AssigneeContinental Automotive Systems, Inc.
InventorJuan Carlos Garcia-Flores
Life of this patent
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Abstract
Leakage current between two electrical energy sources in a vehicle, one of which is normally isolated from ground, can be detected and measured by connecting voltage dividers across the two sources. The center node voltage of the first voltage divider, connected across a first battery, is measured. Thereafter, the center nodes of both dividers are connected to each other and the center node voltage of both dividers is measured and compared to the first voltage obtained from the first divider. A difference between the two voltages indicates a leakage current from the second battery to ground.
Claims15
A method of detecting a leakage current between two electrical energy sources in a vehicle, the method comprising:
- connecting a first voltage divider having a first center node, between the first power source and a reference potential for the vehicle;
- determining a first voltage at said first center node;
- connecting a second voltage divider having a second center node across the second power source;
- connecting the second center node and the first center node to each other;
- determining a second voltage at said first center node responsive to the connection of the second center node to the first center node, the second voltage being determined relative to the reference potential;
- and
- determining whether the first and second voltages are unequal;
- whereby unequal first and second voltages indicates a leakage current flowing from said second power source to at least one of the first power source and said reference potential.
An apparatus for detecting a leakage current conducted between two electrical energy sources in a vehicle having a chassis, which carries a reference potential voltage, the apparatus comprising:
- a first voltage divider having a first center node, the first voltage connected across a first, low-voltage power source and a reference potential for a vehicle;
- a second voltage divider having a second center node, and which is connected across a second power source, which is electrically isolated from the first power source;
- a switch, configured to provide a removable connection between the first center node and the second center node;
- a processor, configured to be selectably coupled to the first center node when the switch is in a first position and coupled to the connection between the first center node and the second center node when the switch is in a second position, the processor being additionally configured to determine a first voltage when the switch is in the first position and determine a second voltage when the switch is in the second position and further configured to determine a difference between the first and second voltages.
An apparatus for detecting a leakage current between two batteries in a vehicle, the apparatus comprising:
- a processor;
- a switch, operatively coupled to and controlled by the processor and operatively coupled between first and second voltage dividers, which are selectably attachable to the first and second batteries;
- and
- a non-volatile memory device coupled to the processor and storing program instructions, which when executed cause the processor to:
- connect the first voltage divider having a first center node, between the first battery and a reference potential for the vehicle;
- determine a first voltage at said first center node;
- connect the second voltage divider having a second center node across the second battery;
- connect the second center node and the first center node to each other;
- determine a second voltage at said first center node responsive to the connection of the second center node to the first center node through actuation of the switch, the second voltage being determined relative to the reference potential;
- and
- determining whether the first and second voltages are unequal.
Dependencies are inferred from the claim text.