METHOD AND APPARATUS TO MONITOR LOSS OF GROUND ISOLATION OF AN ELECTRIC MOTOR DRIVE CIRCUIT

摘要

A method for monitoring electric isolation of a high voltage DC bus to detect ground isolation faults includes monitoring voltage differentials between a positive DC electric power bus and a negative DC electric power bus and a chassis ground. Electrical isolation between each of the positive and negative DC electric power buses and the chassis ground is monitored using a ratio of the voltage differentials.