Grid Voltage Drop effects on the Control of Wind Turbine driven a DFIG with accurate model

the grid-connected doubly-fed induction generator (DFIG) incorporated into a wind turbine generating system (WTGS) has been widely exploited for electricity production. This paper investigates the effect of grid voltage drop on the characteristic of a Direct Power Control (DPC) for a DFIG-based WTGS using an accurate model. In the conventional DPC strategy, the DFIG mathematical model with neglected saturation assumption has been used to elaborate active/reactive power estimators when implementing the DPC for the DFIG, which can perform well under normal network conditions. However, once the grid voltage drop appears, the performance of DFIG-based WTGS is degraded. For this, an accurate DFIG mathematical model taking into account magnetic saturation effects is developed. Simulations were performed on a wind turbine driven by a 7.5 KW DFIG using Matlab/Simulink. The efficiency of the developed saturated model and the influence of the saturation effect on the performance of the DPC-controlled DFIG under grid voltage drop fault are all verified by the simulated results.