Transient Stability Analysis and Enhancement of DFIG-Based Wind Turbine With Demagnetization Control During Grid Fault

Demagnetization control is the most commonly used low voltage ride through (LVRT) method for doubly fed induction generator (DFIG)-based wind turbines (WTs). However, the WT may suffer from transient instability issues under demagnetization control, which has not been revealed in existing studies. To fill this gap, the transient model of DFIG-based WT with demagnetization control has been established. Then, the transient stability has been analyzed by using the Lyapunov's energy function and inverse trajectory method, in which the influence of multiple parameters (e.g., grid conditions, demagnetization coefficient, PLL control parameters) on transient stability have been revealed. It is discovered that the improper demagnetization coefficient will lead to new transient instability issue, and damping energy along trajectory can contribute to the transient stability. On this basis, a trajectory reconstruction control has been proposed to enhance the transient stability of DFIG-based WT with demagnetization control. Finally, the analysis and proposed method are validated by hardware-in-the-loop (HIL) experiments.