Insulation impedance detection system and detection method

Abstract

The invention discloses an insulation impedance detection system and detection method. The system comprises a standard bias resistor switching module, an insulation data collection module, a pull-up bias power collection module, a filtering module and a processor module. The processor module obtains an impedance value of a positive electrode ground insulation impeder and the impedance value of a negative electrode ground insulation impeder in a high voltage system, based on a first pull-up bias power voltage and a second pull-up bias power voltage output by the pull-up bias power collection module, and a first positive electrode collection voltage, a first negative electrode collection voltage, a second positive electrode collection voltage and a second negative electrode collection voltage output by the filtering module, and further determines an insulation state of the high voltage system. According to the system and the method, ripple interference in the high voltage system is filtered through utilization of the filtering module, processes of obtaining the impedance value of the positive electrode ground insulation impeder and the impedance value of the negative electrode groundinsulation impeder are irrelevant to a high voltage power supply, so insulation impedance detection precision is improved.

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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