增强型Z源逆变器的直流链电压直接控制策略

增强型Z源逆变器与传统Z源逆变器相比不仅具有很强的升压能力,而且很大程度减小Z源网络电容、开关器件电压应力.但Z源逆变器现有控制策略是通过测量电容电压构建闭环间接控制直流链峰值电压,而Z源网络电容电压并不能准确反映直流链电压的动态特性.为了提高增强型Z源逆变器的直流链电压动态响应速度和控制精度,借助于数学建模,提出一种直流链电压直接控制的闭环控制策略,通过直接测量直流链峰值电压来提高系统的控制精度,采用电感内环、直流链峰值电压外环的双闭环控制提高了系统的动态响应速度,有效地抑制非最小相位特性对系统地影响.仿真和实验结果证明控制器对输入和负载扰动具有很好抑制能力.

DC-link voltage direct control strategy of enhanced Z-source inverters

Compared to traditional Z-source inverter(ZSI) topology,enhanced Z-source inverter can gain high voltage conversion factor,and decrease voltage stress across both Z-source capacitor and switching devices.The previous control strategy in ZSI most achieved a desired peak DC-link voltage through measurement of capacitor voltage.But transient character of peak DC-link voltage can not be reacted accurately by Z-source capacitor voltage.In order to improving the system’s transient response ability and controlling accuracy,this article studies a direct peak DC-link voltage control strategy in enhanced Z-source inverter designing controller based on small signal model and constructing closed-loop by measuring Z-source DC-link voltage directly.The dynamic performance and control accuracy were improved,and the influence of non-minimum-phase characteristic was eliminated significantly.The simulation and experimental results show the disturbance rejection ability of input voltage and load.