Insulation resistance detecting control circuit and detecting method of electric vehicle

Abstract

The invention discloses an insulation resistance detecting control circuit and detecting method of an electric vehicle. The circuit is based on a balanced bridge; a light-control type relay is used for controlling opening or closing of corresponding bridge arms of the bridge; a high-precision instrumentation amplifier is used for amplifying a weak voltage signal and realizing voltage polarity conversion. On the basis of the basic characteristics of the above circuit, a four-step insulation resistance calculation method is designed. The insulation resistance detecting control circuit and the detecting method, the insulation resistance of the positive and negative terminals can be measured simultaneously; online detection is realized; and the precision and reliability are high.

Description

technical field [0001] The invention relates to an insulation resistance detection control circuit and a detection method, in particular to an electric vehicle insulation resistance detection control circuit and a detection method thereof. Background technique [0002] Electric vehicles use the power battery pack as the energy source of the whole vehicle. Usually, the power battery voltage of electric vehicles is much higher than 36V, even reaching several hundred volts, far exceeding the safe voltage range of the human body. Therefore, the positive and negative poles of the power battery pack must be well insulated from the vehicle to ensure the personal safety of the drivers and passengers. [0003] Since electric vehicles are complex mechatronic products, including power batteries, drive motors and their controllers, on-board chargers, auxiliary battery charging devices and other high-voltage electrical appliances, the working conditions of these components are relatively...

AI Technical Summary

Problems solved by technology

Although this method has the advantages of simple measurement, it has the following disadvantages: (1) the use of mechanical switch relays has low breaking sensitivity, mechanical wear, and low reliability; (2) multiple operational amplifiers are used, the consistency of the circuit is poor, and the accuracy lower

This method can detect the simultaneous decrease of the insulation resistance of the positive and negative terminals, and has high reliability. However, the injected signal will cause the ripple of the DC system to increase, which will affect the quality of the power supply, and then affect the sampling accuracy.

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