Multipoint electric automobile insulation test system and detection method thereof

Abstract

The invention discloses a multipoint electric automobile insulation test system and a detection method thereof. A test system circuit comprises a power battery, a battery voltage sampling circuit, a multichannel voltage switching circuit and isolation amplifier unit, a voltage measuring and controller unit, a multi-monitoring-point switching circuit and an equivalent insulation resistor set for k monitoring points of anode and cathode pairs of a power battery, wherein k is an positive integer larger than or equal to one. The detection method comprises three steps, and the insulation condition of all detection points and the power battery can be acquired respectively through detection and calculation. The multipoint electric automobile insulation test system is simple in circuit and low in cost, and under the AD condition that 12 or more bits are selected, the measuring precision is better than 2.5%. The switching path numbers of monitoring points only need to be increased, the insulation condition of the power battery of an electric automobile to all the monitoring points can be measured randomly, and the traveling safety of the electric automobile can be guaranteed.

Description

technical field [0001] The invention relates to the technical field of electric vehicle insulation monitoring, and relates to a power battery insulation performance test used in the safe operation of electric vehicles. Background technique [0002] With the continuous development of the electric vehicle industry, in order to improve the power performance and energy utilization rate of electric vehicles, and to meet certain power requirements, electric vehicles often use multiple batteries in series, and insulation problems may occur between the battery and the chassis . Moreover, as the voltage of the power battery is getting higher and higher, in order to improve the performance of electric vehicles, it has risen from the original tens of volts to the current wide range of 90-500V. In this way, in the actual operation of the car, due to the complex working environment, vibration, sharp changes in temperature and humidity, corrosion of acid and alkali gases, etc., the insul...

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Problems solved by technology

Among them, the balance bridge method has high requirements on the accuracy of the bridge circuit, and it cannot be measured accurately when the insulation of the positive and negative poles drops at the same time; while the injection signal method will not only increase the ripple of the DC system and affect the quality of power supply, but also the system The distributed capacitance directly affects the measurement results, resulting in a decrease in measurement accuracy, and at the same time the circuit is complex and the cost is high

In addition, in the patented technology using the above method, it is not scientific and comprehensive to only measure the insulation performance of the positive and negative electrodes of the battery on the chassis of the car. Great hazard, so multi-point measurement is a must

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