Criteria and Enhancement of Fast Inertial Response for DFIG-Based Wind Turbines

Inertia control has been a mandatory requirement for wind turbines (WTs). However, existing research pays more attention to the inertia control methods, especially the power boost during the inertial response. The response speed of the inertial response is hardly discussed. Therefore, the letter makes efforts to explore the methods to evaluate and enhance the response speed for the inertial response. First, the phase motion model for doubly fed induction generator-based WTs is illustrated as the foundation of inertia analysis. On this basis, the reason for the phase diagram of the inertia transfer function can evaluate the response speed is explained, and the response speed of the inertia control in the power loop and phase-locked loop is compared. Furthermore, the underlying mechanism for enhancing the response speed is revealed and an optimized inertia control method is proposed. The proposed method significantly improves the response speed while maintaining the power boost by proper parameter design. Finally, the analysis and proposed method are validated by the experiments.