A diagnosis electric circuit for relays

Abstract

The invention discloses a diagnosis electric circuit for relays. A plurality of relays is in series connected between a power supply terminal of an electric vehicle and a load / charging terminal. The diagnosis electric circuit for relays includes multiple common-ground bleeder branches, an isolation unit and a judgment unit. Each bleeder branches is used for obtaining a terminal voltage of each relay and performing voltage sharing then outputting; the isolation unit is used for performing isolation transition and transition to multiple shared voltage output by the multiple shared voltage and then outputting the shared voltage to the judgment unit; the judgment unit is used for performing a comparison between the comparison information of the shared voltage on two ends of each relay and thedrive state of the corresponding relay, and the diagnosis results of each relay is obtained. Compared with the prior art, two reference ground of a crossover voltage sampling scheme are merged to onereference ground, through optimizing a resistance typology of the scheme, so that the problem of latent reverse current is avoided.

Description

technical field [0001] The invention belongs to the technical field of relays, and more specifically, the invention relates to a relay diagnosis circuit. Background technique [0002] Relay status diagnosis is an important function in new energy electric vehicles and other fields. This function is helpful for timely diagnosis and discovery of risks in abnormal states such as relay adhesion and open circuit. Personal property damage caused by failure. [0003] With the rapid promotion and popularization of new energy vehicles, more and more attention has been paid to the failure consequences of the indispensable high-voltage relays, and more and more attention has been paid to how to realize relay status diagnosis in a simple, effective and low-cost manner. [0004] In the disclosed relay diagnosis circuit, there are following defects: [0005] 1. In order to solve the problem that the use of relay auxiliary contacts to detect whether the relay fails is not reliable enough,...

AI Technical Summary

Problems solved by technology

However, this crossover voltage sampling will cause a potential reverse current path in the circuit outside the relay, and if the circuit eventually forms a negative voltage and is applied to the high-voltage equipment that is sensitive to negative voltage, it will cause damage to the high-voltage equipment

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