Pre-charging circuit fault detection method and device

Abstract

The invention provides a pre-charging circuit fault detection method. A pre-charging circuit comprises a power supply, a switching device, a pre-charging resistor and a support capacitor. The pre-charging circuit fault detection method comprises the following steps: obtaining a voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality ofdifferent pre-charging time; and judging whether the pre-charging circuit fails or not based on the voltage of the support capacitor and a preset voltage threshold.

Description

technical field [0001] The invention relates to a control method of a high-voltage system, in particular to a method and device for detecting a fault in a pre-charging circuit. Background technique [0002] Common high-voltage systems, such as power batteries of electric vehicles, require pre-charging circuits to solve the problem of sudden changes in voltage and current. figure 1 A schematic circuit diagram of the pre-charging circuit is shown, and the pre-charging circuit includes a switching device K for controlling the on-off of the pre-charging circuit 2 , the precharge resistor R and the support capacitor C. The support capacitor is connected in parallel to both ends of the load L, and the switching device K 2 A switching device K that is connected in series with the pre-charging resistor R and is connected to the control load circuit 1 in parallel. On closing the switching device K 1 Before, first closing the switching device K 2 , turn on the pre-charging circu...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, it is usually judged whether the precharging circuit has completed precharging by judging whether the voltage of the supporting capacitor C is equal to the voltage of the power supply B. This judgment can be made when the precharging time reaches the expected full time of the supporting capacitor, or Continuously judge whether the pre-charging process is completed within a period of time, but the two judging methods are based on the pre-charging time approaching or exceeding the time required for a complete pre-charging before judging whether the pre-charging process is complete or a fault occurs

[0004] When there is a problem with other parts of the vehicle or multiple restarts in a short period of time, repeated pre-charging process for several times may cause damage to the components of the pre-charging circuit such as the pre-charging resistor R

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