Patent ID: 9274159
Filing Date: 2016-03-01
CPC Classification: B60L,G01R,Y02T

Claim Text:
1. A method for monitoring an electric power circuit configured to transfer a power signal to a torque module, said electric power circuit electrically isolated from a chassis ground, the method comprising: injecting a common voltage component into a common mode voltage of electrical phases of the electric power circuit during operation while the electrical phases are electrically energized with an AC PWM voltage and monitoring a negative-ground voltage and a positive-negative voltage of the electric power circuit; determining an AC line resistance indicating an electric resistance between the electric power circuit and the chassis ground, based upon a relationship between the negative-ground voltage, the positive-negative voltage, the injected common voltage component, and an equivalent isolation resistance of the electric power circuit; and detecting a fault in electrical isolation between the electric power circuit and a chassis ground based upon the AC line resistance.