城轨车辆用薄膜电容性能退化影响研究

Study on Degradation Effect of Film Capacitors for Urban Rail Vehicles

薄膜电容失效前的性能退化对地铁车辆的影响常被忽视。以地铁车辆辅助供电系统中三相滤波电容为例,基于其性能退化特征在Matlab中建立了电容性能退化模型,结合实际运行中辅助供电系统的载荷变化和电网产生的谐波干扰进行了仿真分析。结果表明:电容性能退化会导致输出电压有效值降低,电压谐波含量大大超过标准值。当电容容值下降到一定值时甚至会引起LC滤波电路发生谐振,系统输出电压THD到了24.24%,对辅助供电系统的正常工作造成严重影响。本研究可对地铁车辆用薄膜电容的可靠性设计提供理论参考,对地铁车辆的智能运维有重要的实用价值。

The effect of film capacitor performance degradation before failure on subway vehicles is often ignored.Taking the three-phase filter capacitor in the auxiliary power supply system of subway vehicles as an example,a capacitor performance degradation model was established in Matlab based on its performance degradation characteristics,and the simulation analysis was carried out in combination with the load change of the auxiliary power supply system and the harmonic interference generated by the power grid in actual operation,the results showed that the degradation of capacitor performance would lead to the reduction of the effective value of the output voltage,and the voltage harmonic content was greatly higher than the standard value.When the capacitance value dropped to a certain value,it would even cause the LC filter circuit to resonate,and the system output voltage THD would reach 24.24%,which would seriously affect the normal operation of the auxiliary power supply system.This study can provide a theoretical reference for the reliability design of film capacitors for subway vehicles,and it has important practical value for the intelligent operation and maintenance of subway vehicles.