Sub-synchronous oscillation suppression strategy for weak AC grid-connected systems of direct drive wind turbines based on dual phase-locked loop compensation current

Authors

Zewen LI, School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaFollow
Dexuan JIAO, School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China
Guolin DING, Jingtai Coal Industry Co., Ltd., Jingmei Group, Baiyin 730400, China
Guorui WU, School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China
Yazi LUO, School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China
Hu XIAO, School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China
Yuanchuan WANG, School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China

Keywords

direct drive wind turbine; sub-synchronous oscillation; weak AC power grid; double phase-locked loop; sub-synchronous damping controller

Abstract

The dynamic interaction between the control system of direct drive wind turbines and weak AC lines can easily cause sub-synchronous oscillations.Therefore, a sub-synchronous oscillation suppression strategy based on dual phase-locked loop （PLL） compensation current is proposed.By derivation of the transfer function model of the system, the influence of the interaction between the wind turbine control system and the AC line on the stability of the grid-connected system is analyzed, and the mechanism of sub-synchronous oscillation of the system is revealed.On the basis of traditional additional sub-synchronous damping control （SSDC）, the phase disturbance of the PLL is considered, and a compensation current is introduced into the voltage outer loop control system of the grid side converter （GSC） of the wind turbine through a dual PLL.This aims to weaken the interaction process that causes sub-synchronous oscillation between the GSC of the wind turbine and the AC line, thereby suppressing the sub-synchronous oscillation.The simulation results verify the suppression effect of the proposed method under the conditions of changes in power grid intensity and wind speed.

DOI

10.19781/j.issn.1673-9140.2025.05.012

First Page

119

Last Page

129

Recommended Citation

LI, Zewen; JIAO, Dexuan; DING, Guolin; WU, Guorui; LUO, Yazi; XIAO, Hu; and WANG, Yuanchuan (2025) "Sub-synchronous oscillation suppression strategy for weak AC grid-connected systems of direct drive wind turbines based on dual phase-locked loop compensation current," Journal of Electric Power Science and Technology: Vol. 40: Iss. 5, Article 12.
DOI: 10.19781/j.issn.1673-9140.2025.05.012
Available at: https://jepst.researchcommons.org/journal/vol40/iss5/12