一种牵引供电系统负载电压谐波抑制策略

A Strategy of Load Voltage Harmonic Suppression in the Traction Power Supply System

将电力电子变压器(PET)应用于牵引供电系统,可有效解决电气化铁路存在的电能质量问题。因此针对牵引供电系统负载电压谐波问题,以输出侧并联的PET为研究对象,提出了一种抑制PET输出侧电压谐波的主从控制策略。首先阐述了PET的拓扑结构及工作原理,其次分析了造成PET输出侧电压畸变的原因。基于此,利用PET输出侧从逆变器可用容量来补偿负载电流中的谐波分量,而主逆变器仅提供负载电流中的基波分量,并维持PET输出端电压稳定。所提控制策略将电能质量治理功能嵌入到从逆变器控制策略中,有效降低了输出端电压的畸变率。最后,基于PSCAD仿真与实验验证,对所提控制算法的有效性进行了验证。

The application of power electronic transformer(PET)in traction power supply system can effectively solve the power quality problems of electrified railways.Therefore,aiming at the problem of load voltage harmonics in traction power supply system,take PET connected in parallel with output side as the research object,a master-slave control strategy was proposed to suppress the voltage harmonics on the output side of the PET.Firstly,the topological structure and working principle of PET were described.Secondly,the causes of voltage distortion at the PET output side were analyzed.Based on this,the available capacity of slave inverter at PET output side was used to compensate the harmonic component of load current,while the main inverter only provided the fundamental component of load current and maintains the stability of PET output voltage.The proposed control strategy embeds the power quality control function into the control strategy of the slave inverter,which effectively reduces the distortion rate of the output voltage.Finally,the effectiveness of the proposed control algorithm was verified by PSCAD simulation and experimental verification.