Low Frequency Oscillations Induced by Virtual Synchronous Controlled DFIG-Based Wind Turbines

The decline of system inertia caused by the integration of wind turbines (WTs) greatly threatens the frequency stability of power system. Virtual synchronous controlled (VSynC) wind turbines are thought to be one of the solutions of this problem because they can provide inertia to power system. Existing literature focuses on the impact of VSynC WTs on conventional synchronous generators (SGs), but the electromechanical oscillation caused by VSynC DFIG-Based WTs are rarely studied. In this paper, low frequency oscillation induced by VSynC DFIG-Based WTs is confirmed to exist. Then, a linearized model of VSynC DFIG-Based WTs is derived. The impact mechanism of operation areas and control parameters on low frequency oscillations is studied through the open-loop transfer function of a simple system with VSynC DFIG-based WT integrated. Finally, the analysis results are verified through time-domain simulation.