Open AccessAnalysis of Persistent Oscillation Mechanism and Low Frequency Coupling Characteristics of Power System From the Perspective of Grid-Connected Converter
Author(s) -
Qi Wang,
Xingyong Zhao,
Peng Wang
Publication year - 2021
Publication title -
ieee access
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 127
ISSN - 2169-3536
DOI - 10.1109/access.2021.3135376
Subject(s) - aerospace , bioengineering , communication, networking and broadcast technologies , components, circuits, devices and systems , computing and processing , engineered materials, dielectrics and plasmas , engineering profession , fields, waves and electromagnetics , general topics for engineers , geoscience , nuclear engineering , photonics and electrooptics , power, energy and industry applications , robotics and control systems , signal processing and analysis , transportation
The voltage disturbance in the weak grid will cause frequency coupling and even persistent oscillation of the grid current of grid connected converter in power system. From the perspective of grid-connected converter, this paper establishes a unified complex variable model of disturbance frequency / coupling frequency in grid connected system, analyzes the evolution mechanism from SIDO (Single Input Double Output, SIDO) to DIDO (Double Input Double Output, DIDO) of grid connected converter, clarifies the relationship among voltage disturbance, grid impedance and frequency coupling. Then a robust current control strategy based on improved PLL structure has been proposed. Compared with the traditional method, this paper demonstrates that the coupling frequency component is the main cause of instability or oscillation, and the improvement of low frequency characteristics is helpful to enhance the adaptability of the converter to the weak grid. Finally, the correctness of the theoretical analysis is verified by the experimental platform.