Insulation detection method of electric automobile

Through the polarity differential filtering and temperature compensation mechanism, the pulse width is dynamically adjusted, which solves the problem of reduced insulation detection accuracy during dynamic load switching of electric vehicles and realizes accurate insulation detection and fault location of high-voltage systems.

CN120621055APending Publication Date: 2025-09-12GUANGXI TECHCAL COLLEGE OF MACHINERY & ELECTRICITY +1
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Patent Information

Application Number
CN202510873161.X
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-06-26
Publication Date
2025-09-12

AI Technical Summary

Technical Problem

During the dynamic load switching process of electric vehicles, the insulation detection accuracy decreases due to the coupling of electromagnetic interference, impedance fluctuations and capacitive effects. Existing methods are unable to achieve fast and accurate extraction of microampere-level currents, resulting in missed fault reports or false alarms.

Method used

It adopts polarity differential filtering and independent threshold judgment, combined with dynamic pulse width adjustment and temperature compensation mechanism, and realizes accurate insulation detection of high-voltage systems by correlating capacitance and insulation resistance through time constant.

Benefits of technology

It effectively suppresses common-mode interference and impedance fluctuations during dynamic load switching, ensures the accuracy and stability of measurement results, and improves the reliability of insulation detection and fault location accuracy of electric vehicle high-voltage systems.

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Abstract

The invention discloses an insulation detection method for an electric automobile, belongs to the technical field of high-voltage safety monitoring of the electric automobile, and solves the problem that the insulation detection precision is reduced due to electromagnetic interference, impedance fluctuation and capacitive effect coupling in a dynamic load switching process. According to the scheme, a test sequence of discrete frequency points is applied to a high-voltage system; measuring a response current value through a current sensor and calculating a ground distributed capacitance value; connecting a test voltage source between positive and negative electrodes of the high-voltage system through a coupling circuit; applying a first pulse signal during no-load, dynamically setting the width according to the capacitance value, measuring a first response current value, and calculating an initial insulation resistance value; a second pulse signal with the same parameter is applied in the load state window, a second response current value is measured, and differential filtering is carried out in combination with the initial value to eliminate load noise; and comparing the filtered insulation resistance value with a threshold value, and outputting a fault signal when the insulation resistance value is lower than the threshold value. The method is used for monitoring the insulation state of the high-voltage system in real time and accurately early warning faults.
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