采用三次谐波注入法的多电平级联H桥逆变器

Multi-level Cascaded H-bridge inverter based on three harmonic injection method

阐述了级联H桥七电平逆变器拓扑结构和工作原理,分析了比较多电平逆变器常用PWM调制技术的优缺点,得出采用三次谐波注入方法控制多电平逆变器具有两个突出优点:电压调制度可以达到1.15;由N个单元组成的H桥逆变器的负载电压等效开关频率是每个单元开关频率的N倍.通过Matlab/Simulink/仿真软件和DSP实验装置对三次谐波注入法多电平逆变器进行了仿真和实验研究,结果验证了该方法的正确性和可行性.

This paper introduces seven-level Cascaded H-bridge （CHB） inverter and its working principle.The advantages and disadvantage of usual PWM technologies of multi-level inverter are analyzed and compared. We find that multi-level cascaded inverter based on three harmonic injection method has two striking advantages ： 1 ） the voltage modulation index can reach 1.15 ;2） the equivalent switching frequency of H-bridge inverter＇ s load voltage is N times of each cell switching frequency. At last, H-bridge inverter was investigated with simulation and experiment. The results show that the analysis method is correct and feasible.