Sub-Synchronous Oscillation Suppression in Series-Compensated Grid-Connected Doubly-Fed Wind Turbines Utilizing Virtual Inductance on the Rotor Side

To tackle the issue of Sub-Synchronous Control Interaction (SSCI) in doubly fed wind turbines featuring series capacitor compensation, a novel approach is undertaken by creating an impedance model for the Doubly Fed Induction Generator (DFIG). This model utilizes a power outer-loop control method for decoupling, in alignment with IEEE standards. The study extensively examines the genesis and underlying causes of sub-synchronous oscillations. A novel rotor-side suppression strategy, featuring the integration of virtual inductance into the DFIG's rotor control loop, is proposed to mitigate oscillations induced by series-compensated transmission line parameters. Comparative analysis indicates that the inclusion of virtual inductance effectively quells sub-synchronous oscillations. Additionally, a Simulink-based grid-connected DFIG model is constructed, and time-domain simulations are conducted to validate the model's accuracy in predicting grid-connected sub-synchronous oscillations and confirm the efficacy of the proposed suppression technique.