基于模糊自适应PI和串联阻抗校正的并网逆变器控制策略  

Stability Control of Grid Connected Inverter Based on Fuzzy Adaptive PI and Series Impedance Correction

作　　者：周超红 王素娥[1] 高长萍 郝鹏飞[1] ZHOU Chaohong;WANG Sue;GAO Changping;HAO Pengfei(College of Electrical and Control Engineering,Shaanxi University of Science and Technology,Xi’an Shaanxi 710021,China;PetroChina Changqing Oilfield Clean Power Development Project Department,Xi’an Shaanxi 710021,China)

机构地区：[1]陕西科技大学电气与控制工程学院,陕西西安710021 [2]中国石油长庆油田清洁电力开发项目部,陕西西安710021

出　　处：《电子器件》2023年第1期150-156,共7页Chinese Journal of Electron Devices

基　　金：西安市科技计划项目(21XJZZ0003)。

摘　　要：在弱电网背景下,网络阻抗增大,不同耦合点的网络阻抗不同,且随接入点变流器数量及种类的不同而改变,对并网逆变器的稳定运行造成严重威胁。模糊自适应PI控制器可根据具体工况自主改变并网逆变器的环路特性以适应不同的网络阻抗参数,但由于其固有的相位滞后特性,在高网络阻抗情况下难以保证并网逆变器稳定裕度的要求。针对上述问题,在模糊自适应PI基础上,提出了串联虚拟阻抗的校正方法,对逆变器输出阻抗串联感性环节,从而将逆变器等效输出阻抗从阻容性校正为阻感性,提升了系统稳定裕度。最后通过确定最大网络阻抗,并设定45°的最小相位裕度,得到具体的串联阻抗参数,通过控制框图等效变换模拟虚拟阻抗的实现,并通过仿真和1kW实验样机验证了所提方法的有效性。When the position of photovoltaic equipment connected to the power grid changes,the power grid reactance relative to the com-mon coupling point will float,resulting in a wide range of power grid impedance changes,the stability of grid connected inverter is affect-ed,and the design of inverter control system is difficult.Fuzzy Adaptive PI control is a classical method used to control inverter.It has the characteristics of adaptive adjustment of inverter control parameters and can improve the stability of inverter under low impedance condi-tions.However,due to the limited variation range of Fuzzy Adaptive PI control parameters,it can not meet the requirements of system sta-bility margin under high impedance,and the system is at risk of instability.To solve the above problems,based on the fuzzy adaptive PI control,a correction method based on series virtual impedance is proposed.By giving the line impedance value under the worst working condition of the power grid and the stability margin required by the system,the current required series virtual impedance value is ob-tained,and the virtual impedance is connected in series with the output impedance of the inverter,improving the phase margin of inverter output impedance under the condition of high impedance and the quality of grid connected current,and giving the realization process of virtual impedance in control.Finally,the effectiveness of the proposed method is verified by a 1 kW experimental prototype.

关 键 词：弱电网 模糊自适应PI控制 串联阻抗校正 稳定裕度 

分 类 号：TM46[电气工程—电器]