Method and apparatus to detect leakage current between power sources

摘要

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.

主权项

1. 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.