Nonlinear Control of Mppt and Grid Connected for Variable Speed Wind Energy Conversion System Based on the Pmsg

The efficiency of the variable speed wind energy conversion systems (WECS) can be greatly improved using an appropriate control strategy. In this paper, nonlinear control for wind energy conversion system (WECS) based on the permanent magnet synchronous generator (PMSG) is investigated in order to maximize the generated power from wind turbine. The control strategy combines the technique of maximum power point tracking (MPPT) method and sliding mode (SM) nonlinear control theory, that as it is well known, presents a good performance under system uncertainties. The block diagram of the WECS with a back-to-back PWM converter structure and PMSG is established with the dq frame of axes. Considering the variation of wind speed, both converters used the sliding mode control scheme. The objectives of grid-side converter are to deliver the energy from the PMSG side to the utility grid, to regulate the DC-link voltage and to achieve unity power factor and low distortion currents, while a speed controller is designed to maximize the extracted energy from the wind, below the rated power area. Simulation results show the feasibility and robustness of the proposed control schemes for PMSG based variable speed wind energy conversion systems.