中文摘要：

首先分析了单相级联3-H桥单元电压矢量的输出,并比较传统的空间矢量脉宽调制（SVPWM）,得出新型单相SVPWM调制算法,进而推导了三相级联N电平变换器的SVPWM调制算法,并叙述了三相SVPWM调制算法的具体实现过程。继而对级联多电平变换器所涉及的功率单元输出功率不平衡等问题详细进行了分析。最后通过仿真和实验的结果进行了论证。

英文摘要：

The single-phase cascade 3-H bridge unit output voltage vector was analyzed, comparing with the traditional SVPWM modulation, a new type of single phase SVPWM modulation algorithm was proposed, the three-phase SVPWM modulation algorithm cascade N level converter was derived, and the specific implementation process of three-phase SVPWM modulation algorithm was described. The cascade multilevel converter power unit involved in the problems such as unbalanced output power was analyzed. Finally, the simulation and experimental results demonstrate the narrative.