高速铁路车—网间电耦合阻抗特性及稳定性分析

Impedance Characteristics and Stability Analysis of Electrical Coupling between Train and Power Supply Network of High Speed Railway

基于多导体传输理论将AT牵引供电网等效为链式网络,每隔1km设置1个切面从而得到牵引供电网的Π型等效电路模型,再将高速列车的逆变器—电机系统简化为电阻负载,建立列车牵引传动系统模型,从而构成车—网系统模型;采用电流谐波检测法得到牵引供电系统的输出阻抗和网侧变流系统的输入阻抗,运用阻抗比的稳定性分析方法分析牵引变流系统的稳定性,并基于MATLAB软件仿真分析列车位置及其输入阻抗对变流系统失稳的影响。结果表明:当列车输入阻抗小于牵引供电系统输出阻抗时,车—网阻抗为强耦合,变流器控制参数设置不当会引起列车牵引系统不稳定;反之,车—网阻抗为弱耦合,此时列车牵引系统稳定。

AT traction power supply network was equivalent to a chain network based on multi-conductor transmission theory.One section was set up for every other 1km to obtain theΠtype equivalent circuit model of traction power supply network.Then the inverter-motor system of high speed train was simplified into resistance load to establish train traction drive system model.Accordingly,the model of trainnetwork system was built.Current harmonic detection method was used to calculate the output impedance of traction power supply system and the input impedance of line-side converter system.The stability analysis method for impedance ratio was adopted to analyze the stability of traction converter system.MATLAB simulation was carried out to analyze the influence of train position and input impedance on the instability of converter system.Results show that,when the input impedance of train is smaller than the output impedance of traction power supply system,the train-network impedance is strong coupling.The instability of train traction system will occur when the control parameter of converter was improperly set up.Contrariwise,the train-network impedance is weak coupling and the train traction system is stable.