FAULT DIAGNOSING METHOD AND APPARATUS OF POWER ELECTRIC SYSTEM FOR VEHICLE

A fault diagnosis method of a power electric system for a vehicle may include driving an inverter to output an output voltage command for fault detection; measuring a current input to each phase of a motor connected to the inverter; measuring a voltage of the neutral stage of the motor; and determining whether there are faults of a connection member connecting between the inverter and the motor and a relay connected to the neutral stage of the motor based on the measured current input to each phase of the motor and the voltage of the neutral stage.