Insulation test method, master controller and insulation test instrument

Abstract

The invention provides an insulation test method. The insulation test method comprises the following steps: when detecting that a high-voltage component is connected to a high-voltage system loop, acquiring a current first insulation resistance value of the high-voltage system loop according to a preset first operation mode; calculating a targeted insulation resistance value of the high-voltage component according to the first insulation resistance value and an acquired second insulation resistance value, wherein the second insulation resistance value is an insulation resistance value when the high-voltage component is not connected to the high-voltage system loop; and when the targeted insulation resistance value is smaller than a preset standard resistance value of the high-voltage component, determining that the high-voltage component has insulation fault. In the insulation test method provided by the invention, the insulation resistance value of the high-voltage component is calculated according to the insulation resistance values before and after the high-voltage component is connected to the high-voltage system loop, then whether the high-voltage component has the insulation fault or not is judged, and the high-voltage component which has the insulation fault is positioned accurately.

Description

technical field [0001] The invention relates to the electrical field of electric vehicles, in particular to an insulation test method, a main controller and an insulation tester. Background technique [0002] The high-voltage electrical system is an important part of the electric vehicle electrical system. In order to ensure the safety performance of the vehicle, it is necessary to use an insulation tester to regularly or permanently monitor the insulation resistance between the high-voltage DC bus circuit of the electric vehicle and the electric chassis. [0003] Existing insulation testers usually use unbalanced bridge method or pulse injection method to measure insulation resistance. The unbalanced bridge test method tests the insulation resistance speed block, and the test is not affected by the distributed capacitance of high-voltage components. The test accuracy is not high, and it cannot test the symmetrical insulation failure of positive and negative high-voltage DC...

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Problems solved by technology

[0004] In the prior art, the above two methods can only directly measure the overall insulation resistance of the DC high-voltage system circuit of the electric vehicle. When an insulation fault occurs in a certain high-voltage component, it can only be determined that there is a fault in the DC high-voltage circuit, and it is impossible to realize the insulation resistance of the DC high-voltage system. Accurate location of faulty high voltage components

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