When diagnosing whether a contactor is faulty, a typical method involves measuring a voltage differential across the contactor. For example, a first side of the contactor is measured at a battery side connection and a second side is measured at a load side connection. If a small voltage drop across the contactor or no voltage drop is detected across the contactor, the method identifies the contactor as closed. If there is a large voltage drop across the contactor, the method identifies the contactor as open. To measure that the contactor is open, the load side must be discharged by a load connected to the contactor. Under certain conditions, the load takes too long to discharge, leading the diagnostic module to incorrectly flag the contactor as stuck closed.
USPTO Backgrounds
USPTO Backgrounds