The control of the wind power systems by imposing the DC current

In this paper, we present a method for controlling a wind system consisting in a wind turbine (WT) and a permanent magnet synchronous generator (PMSG) so as to achieve the operation in the optimum energy efficient zone at time-varying speeds of wind. It analyzes the operation of a WT in the maximum power zone by changing the generator load, while the wind speed varies significantly over time. The coordinates of the maximum power point (MPP) changes over time and they are determined by the values of the instantaneous wind speed and mechanical inertia. So not always the wind system can be brought quickly to operate in the MPP zone. By measuring wind speed, the optimum dc current (I_CC-_OPTIM) can be obtained, the generator load can be controlled and thus it can extract the maximum mechanical energy at time-varying wind speeds.