Stability Analysis and Oscillation Mitigation of Grid-Forming Doubly Fed Induction Systems Based on Reduced-Order Modeling Generator

The increasing penetration of renewable energy exposes doubly fed induction generator (DFIG)-based wind power systems to weak-grid conditions, making them susceptible to low-frequency and subsynchronous oscillations. Although grid-forming (GFM) control enhances weak-grid adaptability, the resulting high-order small-signal model complicates stability analysis and controller design. This paper establishes a 15th-order state-space model for a GFM-DFIG system. Eigenvalue analysis is performed to identify the dominant oscillation modes and to reveal their sensitivity to controller parameters and grid strength. To reduce computational burden, a model order reduction method combining singular perturbation theory and participation factor analysis is proposed, yielding an eighth-order model that preserves dominant oscillatory characteristics. An additional damping control strategy is then designed using the reduced model. Simulations validate the reduced model’s accuracy and demonstrate the damping control’s effectiveness in mitigating oscillations. This paper provides an effective framework for stability analysis, reduced-order modeling, and damping control design for GFM-DFIG systems.