Insulation resistance detection circuit, method and device for vehicle

Abstract

The invention discloses a vehicle insulation resistance detection circuit, method and device, and relates to the technical field of automatic control, and the vehicle insulation resistance detection circuit comprises a switch KP, a divider resistor R1, a divider resistor R2, a divider resistor Rf, a voltage sampling resistor Rs, an insulation resistor Rp, an insulation resistor Rn and a vehicle-mounted power battery pack. The divider resistor R1, the divider resistor R2, the insulation resistor Rp, the insulation resistor Rn and the vehicle-mounted power battery pack form a Wheatstone bridge; according to the invention, the control resource of the MCU chip and the AD sampling resource of the MCU chip can be saved, devices used by the system are few, the device cost is low, the economic applicability is high, the insulation fault occurring under the working condition that the insulation resistance is seriously unbalanced is directly judged by detecting and judging the balance of the insulation resistance bridge, and the reliability of the system is improved. In the process, detection of an insulation resistance value is not needed any more, shutdown and alarm operation are directly carried out, insulation fault alarm is timely and effective, and the insulation detection process is simple and reliable.

Description

technical field [0001] The invention relates to the technical field of automatic control, in particular to a vehicle insulation resistance detection circuit, method and device. Background technique [0002] The DC voltage of the vehicle-mounted power battery pack of an electric vehicle is usually as high as hundreds of volts or even thousands of volts. The insulation between the two electrodes of the battery pack and between the electrodes and the casing must be good enough to ensure the safety of the battery and the vehicle personnel. Low, it is easy to cause accidents, so the insulation detection of the vehicle-mounted high-voltage power battery pack is necessary for electric vehicles. [0003] Because the vehicle is often in harsh environments such as vibration, high temperature, high humidity, and gas corrosion during driving, the insulation characteristics are prone to change. Once the insulation performance deteriorates, flashover breakdowns between the electrodes of t...

AI Technical Summary

Problems solved by technology

[0003] Because the vehicle is often in harsh environments such as vibration, high temperature, high humidity, and gas corrosion during driving, the insulation properties are prone to change. Once the insulation performance deteriorates, flashover breakdowns between the electrodes of the battery pack are prone to occur, causing huge property losses. Or cause a huge threat to the personal safety of the vehicle personnel; therefore, an insulation detection system with high precision and good reliability is of great significance to ensure the safety of vehicles and drivers

[0004] At present, the existing insulation resistance detection technology includes symmetrical balanced bridge method, asymmetric balanced bridge method, bias resistance switching method and low frequency signal injection method, etc. The above methods usually have complex circuits and high cost of components; More devices are used, the control process is complicated and takes a long time, and the timeliness of the alarm after a fault occurs is not high; or the calculation process is complicated, and the computing power of the controller is too high

[0005] The existing patent discloses a detection circuit and a detection method for the insulation resistance of automobiles. The patent detects the insulation resistance by controlling the orderly access of the resistance bridge arms to the detection circuit. The calculation process of this scheme is simple, but the four-way The way of the resistance bridge makes the control process complicated, the fault detection process is complicated and needs to be set as a dead zone, so the timeliness of the alarm after a fault occurs is not high, and two sets of voltage detection circuits are required, and the components are used more, and the cost is relatively high

Images