FAULT DIAGNOSIS SYSTEM AND METHOD FOR RELAY OF VEHICLE

摘要

The present invention relates to an apparatus and a method for diagnosing defects in a vehicle relay capable of diagnosing whether or not high voltage relays such as a main relay and a free-charge relay are welded without receiving inverter voltage (capacitor voltage of a motor controller) in eco-friendly cars such as electric or hybrid cars. The objective of the present invention is to provide an apparatus and a method for diagnosing whether or not a rapid charge relay is welded in cars. The present invention comprises a power circuit unit applying a voltage to diagnose defects; first resistance connected between both contact points of a relay to be diagnosed and connected to an earth terminal; second resistance connected between the power circuit unit and first resistance in series; a conversion unit converting voltage signals applied to both ends of the second resistance into digital signals when the voltage is applied from the power circuit unit through the second resistance; and a CUP determining whether or not the relay is welded from the digital signal type of voltage signals outputted from the conversion unit. The relay to be diagnosed may be one or more of the main relay, the free-charge relay, and the rapid charge relay.