The purpose of this paper focuses on the adaptive fuzzy proportional integral (PI) method for maximum power point tracking (MPPT) control of variable speed wind turbines equipped with permanent magnet synchronous generators (PMSG) and power electronic converters including a diode rectifier, a dc-dc buck converter and a pulse width modulation (PWM) inverter. This topology is more suitable for small wind energy conversion systems (WECS) due to its robustness, its low cost owing to reduced number of switching devices and its simplicity of control. The control strategy for power management in the wind system is proposed to: i) extract the maximum power by directly adjusting the buck converter duty cycle, ii) regulate the dc link voltage (Vdc), maintain the amplitude and frequency of the grid and balance the power flow between the generator and the grid to meet the load demand. Simulation is carried out using the Matlab-Simpower Systems tool to verify the system dynamic performances. Obtained results confirm the superiority of the adaptive Fuzzy-PI controller over the conventional PI for a wind velocity variation.

Keywords: Wind turbine, Permanent magnet synchronous generator (PMSG), Fuzzy logic controller (FLC)