Analysis of electromagnetic transient characteristics of doubly-fed induction generator under grid voltage swell

The electromagnetic transient characteristics (ETC) of doubly-fed induction generator (DFIG) under grid voltage dip have been extensively studied theoretically, and various control strategies have been proposed. However, the ETC of DFIG under grid voltage swell are less studied. In order to study the influence on the ETC of DFIG under grid voltage swell and the corresponding control strategy, this paper compares and analyzes the steadystate and transient components of the stator flux linkage, rotor induced voltage and rotor current of DFIG under grid voltage swell and dip. It is deduced that DFIG is less prone to rotor overcurrent under grid voltage swell so the crowbar protection circuit is not needed, and the grid voltage amplitude changes little, the rotor side inverter is less prone to overmodulation. An experimental setup and simulation model is implemented with high-voltage ride-through of 1.5 MW doubly-fed wind Turbine. Simulation in addition to experimental results verifies the correctness and effectiveness of the theoretical analysis.