Electric vehicle insulation detection device and method

Abstract

The invention provides an electric vehicle insulation detection device and method. In an insulation detection circuit of the detection device, a first detection unit, a first diode and a second detection unit are sequentially connected in series between the positive electrode of a power battery set and a vehicle body, a third detection unit, a second diode and a fourth detection unit are sequentially connected in series between the negative electrode of the power battery set and the vehicle body, and a first capacitor is connected with any point between the first detection unit and the anode of the first diode and the positive electrode of the power battery set; a second capacitor is connected with any point between the third detection unit and the cathode of the second diode and the negative electrode of the power battery set, wherein the detection unit is formed by connecting a resistor and a switch in series; the method includes the steps that an insulation detection circuit measures the voltage difference of the two ends of a capacitor in the charging process, and insulation resistance between a power battery and the vehicle body is then obtained. According to the device and the method, the insulation resistance between a battery high-voltage system and the vehicle body can be rapidly and efficiently detected, and the safety of the human and the vehicle is improved.

Description

technical field [0001] The invention belongs to the technical field of electric vehicle safety detection, and in particular relates to an electric vehicle insulation detection device and a detection method thereof. Background technique [0002] Electric vehicles use power batteries as energy sources, and the voltage of commonly used electric vehicle power batteries is generally above 300V. The higher the operating voltage of the power battery, the higher the requirements for the insulation performance between the battery high voltage system and the body system. The aging of the insulation medium of high-voltage cables or the influence of humid environment factors will lead to a decrease in the insulation performance between the high-voltage circuit and the body system, which will pose a threat to the personal safety of passengers and affect the performance of the in-vehicle controller. Therefore, the power battery system needs to have very reliable insulation to ensure the ...

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Problems solved by technology

[0004] Among the above-mentioned insulation detection methods, the injection signal method needs to inject a voltage signal, so the hardware and software for generating the signal are relatively cumbersome, and it may affect the original system of the vehicle at the same time, and the reliability is low; while the resistance voltage divider method often needs to introduce Resistance, man-made insulation reduction, and the hardware will be more complicated, and the operation is not convenient enough

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