An insulation resistance detection system and detection method

Abstract

The invention discloses an insulation impedance detection system and a detection method, comprising: a standard bias resistance switching module, an insulation data acquisition module, a pull-up bias power supply acquisition module, a filter module and a processor module, the processor module is based on the pull-up bias The first pull-up bias power supply voltage and the second pull-up bias power supply voltage output by the power acquisition module, and the first positive collection voltage, the first negative collection voltage, the second positive collection voltage and the second negative collection voltage output by the filter module The voltage is collected to obtain the impedance value of the positive pole-to-ground insulation resistance and the negative pole-to-ground insulation resistance in the high-voltage system, and then determine the insulation state of the high-voltage system. The present invention filters out the ripple interference in the high-voltage system through the filtering module, and the process of obtaining the impedance value of the positive pole-to-ground insulation impedance and the negative pole-to-ground insulation impedance is independent of the high-voltage power supply, thereby improving the insulation resistance. Detection accuracy.

Description

technical field [0001] The invention relates to the technical field of electric vehicles, and more specifically, relates to an insulation resistance detection system and a detection method. Background technique [0002] At present, many components in electric vehicles, including: power batteries, motors, chargers, energy recovery devices, auxiliary battery charging devices, etc., will involve high-voltage electrical insulation problems. Insulation resistance testing in automobiles. [0003] There are mainly two detection methods in the prior art, one is an AC signal injection method, and the other is an external resistance method. (1) The AC signal injection method is: inject a low-voltage AC signal of a certain frequency between the positive and negative electrodes of the power battery as a test signal, and obtain the insulation resistance of the power battery system by measuring the feedback of the high-voltage system. Since the test signal forms ripple interference in t...

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Problems solved by technology

Since the high-voltage power supply is involved in the two expressions, and the voltage level of the high-voltage power supply covers a wide range of 90V to 500V, the voltage value of the high-voltage power supply will change frequently during the operation of the electric vehicle, resulting in the collected high-voltage power supply. The voltage value is unstable, therefore, it is easy to cause a large error in the obtained insulation resistance, or even invalid

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