一种基于三电平矢量调制波的多电平调制方法

以五电平为例简述了多电平空间矢量调制（SVM）的实现方法，在此基础上分析了多电平SVM与多电平载波调制的联系和区别，指出多电平SVM比载波调制在开关组合的选择上更加灵活，使得多电平SVM更有利于输出电压波形的优化和输入直流侧的功率平衡，但是多电平SVM的实现相对复杂。因此文中提出了一种改进的多电平调制方法，该方法基于三电平矢量调制波，折衷了多电平SVM和载波调制的优缺点，既利用了SVM在调制波过零点附近增加开关次数来减小输出电压波形畸变的优点，又可以通过三电平矢量调制计算出调制波，使用载波调制的方法实现，使得该方法的计算量不会随着电平数的增多而大幅度增加。所建立的五电平实验模型验证了该方法确实可行。

A New PWM Scheme for Multi-level Inverter Based on the Modulation Waves of Three-level SVM

Based on the universal method of multi-level SVM, the selection of switching sequences is analyzed and compared for the multi-level SVM and multi-level carrier-based modulation. It is presented that the multi-level SVM can select more switching-sets, which can be used to optimize the output voltage or to balance the DC power. Unfortunately it is complex to achieve multi-level SVPWM, so an improved PWM scheme is proposed in this paper, which is based on the modulation waves of three level SVM. This proposed method optimizes the output voltage harmonics by adding switches, and can be achieved by a three-level SVM, hence the calculation cost does not increase when the levels increase. Finally, a five--level test circuit is built to verify the PWM scheme.