Z源逆变器空间矢量调制的新策略

与传统逆变器相比,Z源逆变器允许逆变桥臂直通,通过控制一个周期内直通状态的时间便可实现输入直流电压的升降变换。首先,分析两种Z源逆变器的改进型拓扑并详细说明其工作原理;接着,阐述了Z源逆变器的空间矢量调制方法,进而提出一种新的基于直通零矢量作用时间分配的调制策略,以充分利用传统零矢量,并对开关表进行优化,减小损耗,实现最大升压,充分提高逆变器工作性能;再基于Matlab/Simulink仿真平台搭建了主电路模型,采用基于C语言编程的S函数建模法实现Z源逆变器的新型调制策略进行仿真实验。最后,设计了1台基于DSP TMS320F28335控制的小功率样机,并进行了实验验证。实验波形很好地验证了改进型拓扑的优势,充分说明了新策略的可行性、有效升压性。

Novel Strategy of Space Vector Modulation for Z-source Inverter

Compared with the traditional inverter, Z-source inverter(ZSI) can allow inverter bridges in the shoot-thro-ugh state, and it can achieve the buck-boost conversion of DC input voltage by controlling the time of shoot-through state in one cycle. First, two improved topologies of ZSI are analyzed, and their operating principles are illustrated in detail. Then, the space vector modulation method for ZSI is elaborated, and then a novel modulation strategy based on the working time distribution of the shoot-through zero vector is presented, which can make full use of the traditional zero vector. Moreover, the switch table can be optimized to reduce loss and achieve the maximum boosting, thus improving the performance of the inverter sufficiently. Next, the main circuit model is built based on the simulation platform of Matlab/Simulink, and the novel modulation strategy is realized by S-function modeling method based on C language programming to conduct simulation experiments. Finally, a small power prototype controlled by DSP TMS320F28335 was designed to perform experimental verification. The experimental waveforms verified the advantages of the improved topologies well, which fully validated the feasibility and boosting efficiency of the novel strategy.