Magna International Inc.
HAZARDOUS VOLTAGE PRE-CHARGING AND DISCHARGING SYSTEM AND METHOD

Abstract:

A system for pre-charging and discharging a hazardous voltage direct current system includes a first relay in the form of main contactors, a second relay, and a resistor disposed between first and second electrical contacts. In an initial state, the main contactors are open, and the second relay connects the resistor to the second contacts to operate as a passive discharge. In a startup state, the second relay is switched and pre-charging occurs with the resistor. In an operating state, the main contactors are closed and current flows between the first and second contacts without the resistor. In a shutdown state, the main contactors are opened and the second relay is switched to connect the resistor to the second contacts, and voltage from the second contacts is discharged thermally at the resistor.