Patent ID: 8283929
Filing Date: 2012-10-09
Classification: G01R,H02P

Abstract:
1. Method for monitoring a high-voltage direct-current electrical circuit including an electric energy storage device electrically connected via a positive DC electric power bus and a negative DC electric power bus to an electric machine, the high-voltage direct-current electrical circuit electrically isolated from a chassis ground, the method comprising: monitoring the positive DC electric power bus and the negative DC electric power bus and an electric load associated with the electric machine; periodically sampling electrical signals associated with the positive DC electric power bus and the negative DC electric power bus and calculating respective ground isolation indexes based upon the periodically sampled electrical signals; calculating trend elements using successively calculated ground isolation indexes; characterizing a trend corresponding to the trend elements; comparing the characterized trend with an expected trend, the expected trend associated with the monitored electric load associated with the electric machine; and detecting a potential fault associated with electric isolation of the high-voltage direct-current electrical circuit when the characterized trend deviates from the expected trend.