Review Fixed-speed Wind Turbine Control Strategies for Direct Grid Connection

Direct grid connection without the requirement of power electronics using fixed speed wind turbine control strategies is proposed in this paper. Review two control strategies are adopted to obtain fixed rotational speed for the squirrel cage generator and achieve the objective of the FSWT system. The first control system is a conventional PI-controller applied to the gearbox ratio. The simulation results prove the robustness of the system and the possibility of obtaining constant voltage and constant rotational speed which will lead to a constant frequency at their rated value irrespective of the wind speed. Therefore, it can be connected with the grid without the requirement of power electronics. The second control strategy is by varying the excitation capacitor value with the wind speed. However, this method is limited to a certain range for the wind speed variation which is from 5 to 16 m/s. The simulation results show the achievement of the constant speed for grid connection purpose. The proposed strategies are simple, rigid, and fulfillment for cage generator. In addition, the disadvantage of the FSWT, this is its incapability of achieving maximum power in all wind speeds. The simulation proved that the variation of power coefficient with values below its maximum value under the variation of wind. © 2019 Lavoisier. All rights reserved.