Transient Stability Analysis Method of Grid-Connected DFIG Based on Direct Method

This paper proposed a method to analyze the transient synchronization stability of the grid-connected doubly-fed induction generator (DFIG) in case of power system failure. Firstly, analyze the voltage source converter (VSC) of the DFIG based on the phase-locked loop (PLL), and establish the grid-connected system model based on the PLL reference frame. Then, the swing equation of the system is deduced, and starting from the existence of equilibrium point, the stable area and the transient motion characteristics of the system, combined with the transient energy function method, the transient energy function of the DFIG that is weakly connected to the grid during the system failure is analyzed. State stability characteristics. Finally, a single-machine infinity simulation model of the grid-connected DFIG was built in MATLAB/SIMULINK. The simulation results verified the correctness of the theoretical analysis and the factors that affect the transient stability of the DFIG.