Abstract：In high voltage and high power applications, the neutral-point-clamped (NPC) three- level inverter is a widely used multi-level inverter. However, this type of inverter has neutral-point voltage fluctuations and common-mode voltage problems. To solve these two problems, this paper proposes an improved nearest three virtual vectors (NTV2) modulation. The zero vector, middle vector and large vector are used to redefine the virtual small vector and virtual middle vector. As a result, the maximum common-mode voltage generated by the virtual vector is Udc/6, which is 1/2 of the common- mode voltage generated by the traditional virtual vector. On this basis, it is possible to suppress the fluctuation of the midpoint voltage within a certain range by selecting the values of the distribution coefficient of virtual middle vector reasonably. Compared with the traditional nearest three virtual vectors method, the proposed method can effectively suppress the common-mode voltage and the neutral-point voltage fluctuations. The results of simulation and experiment show that the proposed method is correct and effective.
王志强, 邓臣臣, 谷鑫, 夏长亮. 基于中点钳位型三电平逆变器的改进型虚拟空间矢量调制策略[J]. 电工技术学报, 2017, 32(18): 230-238.
Wang Zhiqiang, Deng Chenchen, Gu Xin, Xia Changliang. The Improved Virtual Space Vector Modulation Strategy Based on Neutral-Point-Clamped Three-Level Inverter. Transactions of China Electrotechnical Society, 2017, 32(18): 230-238.
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2017, Vol. 32 
