Modeling of DFIG Wind Turbine Based on Internal Voltage Motion Equation in Power Systems Phase-Amplitude Dynamics Analysis

Abstract

With the high penetration of power electronics based renewable energy generators being integrated into power grids, dynamic stability problems have become unprecedentedly challenging in modern power systems. Thus, an accurate description of equipment features for system dynamics analysis is desperately needed. Double fed induction generator (DFIG) wind turbines (WTs) are an example of this type of equipment with extremely complex characteristics. To analyze the effect of DFIG WT system behavior characteristics on angle and voltage stability issues, a small-signal DFIG WT model based on the internal voltage motion equation in the electromechanical time-scale is proposed. This approach models from the perspective of the equipment's internal voltage vector, and describes equipment features through the relationship between the input/output power and the internal voltage phase/amplitude. Understanding of the DFIG WT's internal voltage phase and amplitude motion is deepened by developing an analogy to a real dynamical system a rotor's rotation and the voltage across a capacitor. With this approach, the mechanism describing the dynamics of the internal voltage phase-amplitude is elaborated by a physical perspective, particularly system voltage amplitude dynamics. The factors influencing the phase-amplitude dynamics were investigated based on this model in a single-machine system.