基于NPC 5电平H桥级联的牵引变电所谐波分析

Harmonic Analysis of Traction Substation Based on NPC 5-level H-bridge Cascaded Inverter

基于5电平二极管钳位H桥(以下简称5H桥)级联的牵引供电系统是为了取消既有牵引供电系统电分相、改善电能质量、扩大牵引变电所容量而提出的一种新型牵引供电系统。针对目前对该新型牵引供电系统的研究较少、对级联变换器构成的新型牵引变电所的谐波分析基本为空白的现状,本文分析了该牵引变电所输出谐波特性,利用双边傅里叶函数推导了载波移相SPWM(CPS-SPWM)调制策略下的5H桥及5H桥级联牵引变电所输出电压谐波特性,利用Matlab/Simulink搭建该牵引变电所模型,仿真结果表明:该牵引变电所输出电压总谐波失真率可满足国家标准,由此可知该变电所可不用设置滤波电路。且通过仿真和基于FPGA的小功率实验,验证了输出电压谐波分布特性与理论推导一致性,为该系统的进一步研究提供了理论依据。

The traction power supply system based on Diode-Clamped 5-level H-bridge Cascaded Inverter is a new co-phase traction power supply system, proposed for eliminating the neutral section of existing traction power supply system, improving power quality and expanding traction substation capacity. However, research on this system, particularly in the field of harmonic analysis of cascaded inverter-based new traction substation is still scarce. This paper analyzed the harmonic characteristics of the output voltage generated by the substation of the new system. Using double Fourier function, the output voltage harmonic distribution of Diode- Clamped 5-level H-bridge Cascaded Inverter with CPS-SPWM strategy was deduced.. After that,a traction substation based on 5H Bridge cascaded inverter was modeled,simulated and verified,using Matlab/Simulink. The simulation results showed that the total harmonic distortion rate of the output voltage met the national standard, and the filter circuit of the substation can be canceled. Meanwhile, by means of simulation and FPGA based low power experiment, the consistency of harmonic distribution characteristics of the output voltage and the theoretical analysis was verified, which provides a theoretical basis for the further research of the system.