摘要
孤岛模式下的微电网缺少了大电网支撑,使得分布式电源并网逆变器的输出电压易受负载投切影响,进而导致分布式电源输出电能质量下降。为解决该问题,首先将并网逆变器等效成戴维南模型,并通过分析得出在低频段逆变器输出阻抗可代替总等效阻抗的结论,从而提出一种并网逆变器电压电流双闭环改进控制策略。该改进策略通过将负载电流前馈至电流内环的参考输入前达到减小输出阻抗的目的,最终减轻了负载投切对输出电压的影响。此外,该策略在电流前馈前增加了一节低通滤波器,可有效减小不平衡负载对输出电压的影响。仿真结果验证了改进策略的有效性。
The microgrid in the island mode lacks the support of the large grid,which makes the output voltage of the distributed power grid-connected inverter susceptible to load switching,which in turn reduces the quality of the distributed power output power.In order to solve the problem,the grid-connected inverter is equivalent to the Thevenin model,and the conclusion that the output impedance of the inverter in the low frequency band can replace the total equivalent impedance is obtained through analysis.Then,an improved voltage and current double closed loop control strategy of grid-connected inverter is proposed.This improved strategy achieves the purpose of reducing the output impedance by feeding forward the load current to the reference input of the current inner loop,and finally reduces the impact of load switching on the output voltage.In addition,this strategy adds a low-pass filter before the current feedforward,which can effectively reduce the impact of unbalanced loads on the output voltage.The simulation results verify the effectiveness of the improved strategy.
作者
潘健
陈凤娇
刘孙德
张琦
PAN Jian;CHEN Fengjiao;LIU Sunde;ZHANG Qi(Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System,School of Electrical and Electronic Engineering,Hubei Univ.of Tech.,Wuhan 430068,China)
出处
《湖北工业大学学报》
2021年第1期31-35,共5页
Journal of Hubei University of Technology
基金
湖北省重点实验室开放研究基金资助项目(HBSEES201902)。
关键词
微电网
并网逆变器
输出阻抗
电流前馈
低通滤波
microgrid
grid-connected inverter
output impedance
current feedforward
low-pass filtering
作者简介
第一作者:潘健(1962-),男,湖北武汉人,湖北工业大学教授,研究方向为控制理论与控制工程;通信作者:陈凤娇(1994-),女,安徽枞阳人,湖北工业大学硕士研究生,研究方向为光伏发电与新能源并网。
