基于模块化多电平换流器的新型高压变频器拓扑及其控制

为使煤矿设备高效利用能源,达到节能减排的目的,提出了基于模块化多电平换流器(Modular Multilevel Converter,MMC)的新型高压变频器。概述了其基本结构,分析了MMC拓扑及工作机制。以逆变侧为研究对象,建立MMC数学模型,采用建模排序法控制子模块电容电压稳定平衡,通过与不同调制算法对比,载波正负反相层叠脉冲宽度调制技术(POD-PWM)的优势得以凸显。以Matlab-Simulink及RT-Lab半实物仿真设备为实验平台,搭建上位机控制器,实验结果显示换流器运行正常、电容电压稳定平衡,输出电能质量高,谐波含量小,证明了提出的载波正负反相层叠与电压稳定平衡控制相结合的控制策略的可行性,并得出了实验条件下的最佳三角载波频率。

Control method and topology for high voltage frequency converter based on-Modular Multilevel Converter

The fundamental concept of high voltage frequency converter based on Modular Multilevel Converter (MMC) was proposed.To investigate the inverter side，a mathematical model was built through the analysis of the topological structure and working mechanism of MMC.Subsequently the model was controlled by modeling sequencing method to achieve the goal of capacitor voltage stabilization and balancing.Through the comparisons with different methods，the advantage of carrier phase opposition disposition pulse width modulation (POD-PWM) was found.A simulation and experiment had been carried out using Matlab-simulink and Rt-Lab.The result shows that the converter works properly and the capacitor voltage is in a steady state.The output waveform contains few harmonic waves.Therefore the feasibility of POD-PWM and the voltage balancing control methods are verified by the experiment.The best frequency of triangle carrier wave is proposed herein.