Z源逆变器的改进型精确调制策略研究

Research on Improved and Precise Control of Z-source Inverter

深入分析了光伏发电系统中Z源逆变器的控制特点,针对其输出动态性能和升压控制策略导致开关频率增倍等问题,提出一种改进型升压调制策略,在SVPWM的基础上,通过调整同一桥臂开关管的开关时刻,实现在传统零矢量内单周期均匀地插入6段直通状态。与传统升压调制策略相比,该策略不仅在一定程度上稳定了输出性能,而且使开关频率保持最小。另外,针对传统调制策略插入直通时间不精确的问题,提出根据调制信号的斜率来精确控制直通时间大小的策略,使Z源逆变器升压更具有可控性。最后通过仿真和实验结果验证了改进型精确升压调制策略的优点。

This paper analyses the control character of Z-source inverter in depth and according to the question of dynamic performance of output and switching frequency is doubled.This paper presents a new boost modulation strategy, based on SVPWM, the shoot-through zero states is inserted by changing turning on or off time of the same bridge switches.lt realizes the goal of six shoot-through states per carrier period in traditional zero vector.Compared with the traditional modulation strategy, it can stabilize the output of Z-source inverter and reduce the switching frequency significantly.Furthermore ,for the question of accuracy control of traditional modulation shoot-through time, this article is according to the slope of the modulation signal to precisely control the size of shoot-through time ,the Z-source inverter booster will be more controllable.By simulation and experimental, the results are given to demonstrate the new features of the precise control.