基于低频信号法的电动汽车绝缘监测方法研究

Method of insulation detection for electrical vehicle based on low frequency signal

随着能源短缺、环境污染问题的日益严重,以及电动汽车技术的高速发展,电动汽车已经走向实用化道路,因此电动汽车的安全问题也尤为重要。介绍了一种新型的电动汽车绝缘性能监测方法,对外加RC回路注入低频交流信号,通过采样电容两端的实时电压值,计算出电动汽车的绝缘电阻值。该方法可以避免直流电源的影响,实现绝缘性能的离线检测。给出了电路原理图,绝缘电阻的计算公式,硬件电路图和算法实现的流程图。通过搭建实际电路板进行测试,证明了该装置能够准确地计算出绝缘电阻值,并及时报警,有效地进行绝缘监测。

With the increasingly serious problems of energy shortages and environmental pollution, as well as the rapid development of electric vehicle technology, electric vehicles are on the road to be more practical, therefore, the safety is- sues of electric vehicles are particularly important. The paper introduces a new method of monitoring insulating property of electric vehicles, the low frequency AC signal is injected into the additional RC loop, through sampling the real-time voltage value of the capacitor, the insulation resistance value of the electric vehicles can be calculated. This method can avoid the influence of DC power supply and realize the off-line testing of the insulation performance. The paper presents the circuit principle diagram, calculating formula of insulation resistance, the hardware schematic and the software flow pattern. The practical testing on circuit board shows the device can calculate the insulation resistance value accurately, alarm timely and monitor the insulation property effectively.