Vehicle high-voltage DC system insulation monitoring device and monitoring method

Abstract

The invention discloses a vehicle high-voltage DC system insulation monitoring device and a monitoring method, which can compatibly meet insulation performance detection requirements of the system ina state with high-voltage power or without high-voltage power, can perform internal self detection through a built-in standard resistor before the insulation detection function of the system is enabled, can confirm the effectiveness of the insulation detection function and can thus avoid leakage alarm and false alarm of the insulation monitoring device. When the system has no high-voltage power, apositive bus and a negative bus are respectively connected to an insulation detection circuit through a switch, and the standard resistor with the closest resistance range is selected to accurately measure the resistance of an equivalent insulation resistor. When the system has high-voltage power, two circuit states are made through two built-in standard resistors and the series switch, and basedon two measurement results, the overall parallel value of an equivalent insulation resistor of the positive bus to a vehicle body shell and an equivalent insulation resistor of the negative bus to the vehicle body shell is calculated. Based on the measurement result of the insulation resistor, the vehicle insulation performance is evaluated.

Description

technical field [0001] The invention relates to the field of insulation monitoring or leakage detection of a high-voltage direct-current system of a pure electric vehicle or a hybrid vehicle adopting a high-voltage direct-current system. Background technique [0002] Pure electric vehicles or hybrid vehicles contain high-voltage components, including high-voltage power battery packs, high-voltage power distribution boxes, motor controllers, and high-voltage loads such as electric compressors and DC / DC. These high-voltage components will involve insulation problems, and the working environment of electric vehicles is complex. Vibration, temperature, humidity, and component aging will gradually reduce the insulation performance of the vehicle. [0003] When there is only a single-point insulation performance decline in the system, it will not have a significant impact on the system for the time being, but because the metal parts of the vehicle shell are charged at this time, t...

AI Technical Summary

Problems solved by technology

[0008] In addition, the existing vehicle HVDC system insulation monitoring technology does not have the internal self-test (Built-in-test, BIT) function

When the insulation monitoring device itself fails, a false alarm will affect the operation of the vehicle

If the insulation monitoring device cannot detect an insulation fault and a leakage alarm occurs, there is a potential risk

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