动车组静调试验中直流母线电压振荡分析与抑制

Analysis and Suppression of Voltage Oscillation for DC Bus in Static Adjustment Test of EMU

为解决厂内静调试验中高速动车组牵引变流器模拟牵引工况下,其中间直流环节发生电压大幅振荡的问题,该文针对源侧整流器提出引入补偿环节的虚拟电阻控制方法。在单相PWM整流器dq坐标系数学模型的基础上,建立源侧整流器与二次谐振电路并联的等效输出阻抗模型以及牵引逆变单元和辅助变流器的等效输入阻抗模型,并基于上述模型,结合Bode图和Nyquist曲线分析直流环节电压出现振荡的主要原因,即二次谐振电路与恒功率负载间的交互作用会引发中间直流环节电压振荡。所提振荡抑制方法利用虚拟电阻等效增加了负载侧输入阻抗,使得系统开环增益满足禁区稳定判据,可提升系统的稳定裕度。最后,通过仿真和实验验证了该文分析的正确性和所提控制方法的有效性。

In the static adjustment test in the factory,the traction converter of the high-speed EMU has a large voltage oscillation in the intermediate DC link under the simulated traction condition.Therefore,a virtual resistance control method with compensation link was proposed for the single-phase rectifier at the source side.Based on the dq coordinate mathematical model of the single-phase PWM rectifier,this paper built the equivalent output impedance model of the source-side rectifier in parallel with the secondary resonant circuit and the equivalent input impedance model of the traction inverter unit and the auxiliary converter.Then,the reason for voltage oscillations in the DC link was revealed by combining Bode diagram and Nyquist curve,that is,the interaction between the secondary resonant circuit and the constant power load will lead to the voltage oscillation in the intermediate DC link.The proposed oscillation suppression method uses virtual resistance to increase the load-side input impedance,so that the system gain can meet the exclusion zone stability criterion,and the stability margin of the system can be improved.Finally,simulation and experimental results verify the effectiveness of the analysis and the proposed control method.