Relay adhesion detection circuit and detection method thereof

Abstract

The invention relates to a relay adhesion detection circuit and a detection method thereof. The circuit comprises an isolation power supply, a detection unit, a control unit and a judgment unit. The isolation power supply is respectively connected with the judgment unit and the detection unit, wherein the detection unit is used for detecting whether a main negative relay is closed or not and whether residual voltage of a load capacitor is discharged or not under different conditions; the judgment unit is used for analyzing whether the main negative relay is closed or not according to the levelsignal detected by the detection unit so as to obtain an analysis result; and the control unit is used for feeding back to the specified equipment according to the analysis result. According to the invention, adhesion detection is carried out in a level detection mode, the accuracy of relay adhesion detection is improved, and the cost is reduced.

Description

technical field [0001] The invention relates to a relay, more specifically to a relay adhesion detection circuit and a detection method thereof. Background technique [0002] The relay of the high-voltage main circuit of the electric vehicle controls the discharge of the battery system, and the reliable operation of the relay is directly related to the safety of the electric vehicle. Electric vehicles working in the state of relay adhesion may cause safety accidents. If there is a false positive in the sticking detection of the relay, the electric car will not start. Therefore, the BMS (Battery Management System, Battery Management System) needs to reliably detect the sticking state of the relay. [0003] At present, the mainstream relay adhesion detection scheme of BMS is to use the detected physical quantities, mainly voltage and current, to judge different measurement values ​​in different scenarios to draw the conclusion of adhesion failure. The existing mainstream rel...

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Problems solved by technology

[0003] At present, the mainstream relay adhesion detection scheme of BMS is to use the detected physical quantities, mainly voltage and current, to judge different measurement values ​​in different scenarios to draw the conclusion of adhesion failure. The existing mainstream relay adhesion detection scheme needs to be charged when the external charger In the case of insulation detection during the discharge process, the adhesion state of the relay at the RTN (feedback voltage input terminal, RETURNInput Voltage RTN) terminal cannot be detected, and the residual voltage problem of the load capacitor will be encountered during the normal detection process, and it is necessary to wait for the capacitor to discharge for a short time , which reduces the accuracy of detection, and the components that make up the detection circuit are relatively complex and costly

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