**5. Simulation Results**

The simulations in this study were realized in Matlab/Simulink to verify the effectiveness and analysis of the presented method. The sampling frequency of the presented Simulink system was modeled at 20 kHz. The parameters of the PMSG, turbine, and power converter systems are given in Tables A1–A3, respectively. An open source IT2-FLC toolbox in Matlab/Simulink was used in this study. The rules of the IT-2 FLC system were designed to maximize the power generation from the generator. The IT-2 FLC rules were adjusted to generate the optimized gains for the power performance of the wind system based on the PMSG. An IT-2 FLC control system was implemented for the analysis of three different cases of grid fault. The different types of symmetrical and asymmetrical faults were implemented separately at the proper time on the grid side of the PMSG. The simulated fault conditions were as follows:

(i) The 3/φ symmetrical fault was implemented at t = 4.0 s and was cleared at t = 4.5 s;

(ii) The 2/φ asymmetrical fault was implemented at t = 4.0 s and was cleared at t = 4.5 s;

(iii) The 1/φ asymmetrical fault was implemented at t = 4.0 s and was cleared at t = 4.5 s.

The generator with the proposed control method was connected to the grid during all grid fault types. The simulation results illustrate that the IT-2 FLC system gives an appropriate performance for the power generation of the wind system using a PMSG for different scenarios. The rated value of the DC link was 1150 V, the rated value of active power was 1 p.u., the rated value of the electromagnetic torque power was 1 p.u., and the rated value of the reactive power was 0 p.u. in the study.
