Diagnostic circuit and diagnostic method for detecting electric vehicle high-voltage relay fault

Abstract

The invention discloses a diagnostic circuit and a diagnostic method for detecting electric vehicle high-voltage relay fault. The circuit comprises a battery pack for providing power and a driving force for the electric vehicle and a controller for controlling on and off of an electric vehicle switch element. Two ends of the battery pack are connected with an overall electrical device; a main positive relay K+ is serially connected between the positive electrode of the battery pack and the overall electrical device; two ends of the main positive relay K+ are parallelly connected with a relay R and a pre-charging relay Kp; a main negative relay K- is serially connected between the negative electrode of the battery pack and the overall electrical device; both the battery pack and the overall electrical device are respectively connected with the controller; the controller is used for detecting voltage at two ends of the battery pack, voltage at two ends of the overall electrical device, and voltage at the negative end of the battery pack and the positive end of the overall electrical device. Thus, no peripheral circuit needs to be added, the state of the relay is judged only through carrying out cross detection on voltage at the relay end, whether the relay has a fault can be timely detected, remedial measures can be taken timely, the method is simple, convenient and feasible, and no detection risk is added.

Description

Technical field [0001] The present invention relates to the diagnosis of relay faults in electric vehicles, and in particular to a diagnostic circuit and diagnostic method for detecting high-voltage relay faults in electric vehicles. Background technique [0002] Currently, relays used in high-voltage power on and off of electric vehicles are generally divided into two types, one with its own feedback contacts, and the other without feedback contacts. For those with feedback contacts, the actual status of the relay is generally judged through the feedback signal. For those without feedback contacts, the actual status of the relay is generally not judged. The main shortcomings and shortcomings of using these relays: the feedback signal of the system detection relay is generally judged through the IO port of the CPU. However, traditional detection circuits and methods require detection of current and voltage, which are relatively complex. When an adhesion fault is detected, a...

AI Technical Summary

Problems solved by technology

The main disadvantages and shortcomings of using these relays: the feedback signal of the system detection relay is generally judged by the IO port of the CPU

However, the traditional detection circuit and method need to detect current and voltage, which is relatively complicated, and when the adhesion fault is detected, the accident may have already occurred, and timely remedial measures cannot be taken

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