Patent ID: 7586285
Filing Date: 2009-09-08
Classification: B62D,G01R,H02H,H02P

Abstract:
1. A ground-fault detection device for a motor driving circuit comprising: an inverter circuit comprising upper switching devices and lower switching devices which are connected in a bridge and are connected at output sides to respective phases of a motor; electric-current detection resistances connected between respective lower switching devices in the inverter circuit and ground; a switching control circuit which repeatedly causes electric-current detection circuits for detecting values of the electric currents flowing through the electric-current detection resistances during the switching control, wherein, in an event that an electric current value detected by the electric-current detection circuits during the first regenerative time interval becomes equal to or greater than a predetermined electric current value by a ground-fault electric current based on a ground-fault electric energy that is accumulated in an inductance component between the inverter circuit and the motor, a ground-fault is determined to have occurred in connection lines between the inverter circuit and the motor.