考虑牵引网谐波耦合的动车组辅助变流器启动特性分析

动车组辅助变流器运行在谐波含量较高的线路时频繁出现启动失败故障，线路试验结果表明牵引网高次谐波含量与启动失败存在相关性。为研究牵引网谐波电压对交直交型辅助变流器启动过程的影响，首先建立了车载单相变压器谐波模型，分析了牵引网谐波对车载牵引变压器辅助绕组的渗透特性。建立辅助变流器滤波电路谐波模型，对其串联谐振进行理论分析。建立单相不控桥式整流电路的数学模型，理论分析了交流侧谐波对不控整流电路的影响。对发生辅助变流器启动故障的CRH某型动车组的进行测试，对电压进行了谐波分析。根据实测数据对交直交型辅助变流器预充电过程进行仿真分析，与理论分析结果进行了对比。研究结果表明，牵引网谐波会明显渗透到车载牵引变压器辅助绕组，当滤波电路参数与牵引网谐波不匹配时，将激发滤波电路串联谐振，使滤波电容电压严重畸变，会使变流器不控整流阶段的直流侧电压升高，导致辅助变流器出现预充电启动失败故障。对深入研究谐波环境下动车组辅助变流器特性及滤波电路元件参数选取具有一定的指导意义。

Analysis of precharging characteristics of EMU auxiliary converter considering the harmonic coupling of the traction network

When the motor train auxiliary converter runs in the line with high harmonic content, the fault occurs frequently. The test results show that there is a correlation between the high harmonic content of the traction network and the failure of the start. In order to study the influences of the high order harmonics of traction network for the precharging process of the EMU auxiliary converter, the harmonic model of locomotive transformer is established to analyze the permeability characteristics of high-order harmonics for the EMU auxiliary converter system, and the harmonic model of auxiliary converter filter circuit is established to analyze the series resonance. The mathematical model of single-phase capacitor-filtered diode bridge rectifier circuit is presented to analyze the influences of the high order harmonics for DC side voltage. The CRH EMU auxiliary converter with starting fault is measured, and the harmonic measured data are analyzed. Then the computer simulation model of the EMU auxiliary converter is built by Matlab/Simulink to analyze the influences of the high order harmonics of traction network for the precharging process of the EMU auxiliary converter. The results illustrate that the high-order harmonic voltage in the traction network could easily penetrate into the EMU auxiliary converter system, the high-order harmonic voltage nearby filter circuit series resonance frequency will excite series resonance to lead to serious distortion of filter capacitor voltage, which can lead to the DC side voltage increase and auxiliary converter precharging start fault. It is of certain reference meaning for deeply researching the characteristic of EMU auxiliary converter and selection of filter circuit component under harmonic environment. This work is supported by Fundamental Research Funds for the Central Universities (No. A0920502051619-34).