Stability Improvement Method of Grid-connected Inverter Considering Phase-locked Loop Effect in Weak Grid

被引：0
|
作者：
Jiang Y. [1 ]
Si X. [1 ]
Shi H. [2 ]
Zhu M. [2 ]
Ge L. [2 ]
机构：
[1] Electric Power Research Institude of State Grid Jiangsu Electric Power Co., Ltd., Nanjing
[2] School of Electric Power Engineering, Nanjing Institute of Technology, Nanjing
来源：
Dianli Xitong Zidonghua/Automation of Electric Power Systems | 2022年 / 46卷 / 24期
基金：
中国国家自然科学基金;
关键词：
grid-connected inverter; non-ideal generalized integrator; phase-locked loop (PLL); stability margin; weak grid;
D O I：
10.7500/AEPS20220322002
中图分类号：
学科分类号：
摘要：
The grid-connected inverter usually uses the phase-locked loop (PLL) to obtain the grid voltage synchronization information. In a weak grid, the grid impedance cannot be ignored. The voltage disturbance at the common coupling point leads to the output phase angle deviation of the PLL, and then affects the control of the grid-connected current, which is not conducive to the stable operation of the grid-connected inverter. In order to suppress the disturbance introduced by the PLL and enhance the stability of the grid-connected system, an improved small-signal compensation control method based on a non-ideal generalized integrator is proposed. First, the small-signal model of an LCL three-phase grid-connected inverter with the influence of the PLL is established in the dq coordinate system. Then, the variation characteristics of the equivalent output impedance of the grid-connected inverter with and without small-signal compensation are analyzed. For the problem that the improvement effect of the small-signal compensation method on stability margin declines with the increasing frequency, a differential compensation path is introduced based on the small-signal compensation, in which the differential term is equivalently replaced by a non-ideal generalized integrator. When the grid impedance changes in a wide range, the proposed method can ensure a good stability margin for the grid-connected inverter, and enhance the stability and dynamic performance of the grid-connected inverter. Finally, the correctness of the theoretical analysis and the effectiveness of the proposed method are verified by experimental results. © 2022 Automation of Electric Power Systems Press. All rights reserved.
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页码：113 / 120
页数：7
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