三电平逆变器空间矢量调制及中点电压控制

摘要

基于多电平逆变器的中性点电位不平衡问题的研究,对现有的虚拟矢量合成算法进行改进,提出了一种新的分区判断及矢量合成算法.该算法充分利用了新的合成矢量对中性点电压波动的平衡作用,采用十段式对称模式进行调制,有明显的谐波抑制及控制优势,调整小矢量对的作用时间,理论上可以做到最大程度地消除中性点电压的偏移.基于该算法的PSCAD/EMTDC仿真以及实验结果证明其简便易行,有利于计算机数字化实现.%A new algorithm of partition judging and vector composition is proposed, which is based on the study of neutral point potential imbalance of multi-level inverter and the improvement of existing method of virtual vector synthesis. The algorithm takes full advantage of the new synthetic vector's control effect of neutral point potential fluctuation) modulates in ten-stage centered mode, and shows superior performance for the harmonic suppression and the balance control, which can minimize the neutral point potential migration by adjusting small-vector pairs' action time. The convenience and feasibility of the approach has been verified by PSCAD/EMTDC simulation and experimental results, which is good for digital computer realization.