中文摘要：

在多电平变换器研究领域,三电平中点钳位逆变器目前是一种研究比较广泛的一种拓扑结构,但是此拓扑结构容易造成中点电压偏移问题。基于理论上虚拟空间矢量的调制方法可以实现分压电容中点电压平衡控制,因此,为增强中点电压平衡的控制效果,提出调节虚拟中矢量中点电流和分配正、负小矢量作用时间的中点电压平衡控制方法。相对虚拟空间矢量脉宽调制算法和混合式调制算法来说,所采用的可变虚拟空间矢量控制算法简单、实用,能实现三电平NPC变换器中点电位平衡控制。

英文摘要：

The neutral-point （NP）-clamped three-level converter is a widely used topology in the research field of multilevel converters, which suffers from the NP voltage drift as its main technical drawback. Theoretically it is based on the fact that the virtual space vector modulation approach could completely control the balance of neutral-point potential. This paper introduces a new control strategy for better controlling neutral-point potential balance of three-level converters, which modifies the current generated by virtual middle vector and the action time of small vectors pairs to control the neutral-point potential balance in three-level NPC converters. Relative to the traditional algorithms of VSVPWM and Hybrid Modulation, the performance of the strategy proposed in the paper is much better and more practical, and this control strategy can be used to control neutral-point potential balance for Three-level NPC Inverters.