This paper aims at contributing to the modeling and control of a variable speed Wind Energy Conversion System (WEC-System) based on a Squirrel Cage Induction Generator (SCI-Generator). The connection between the SCI-Generator and the main utility grid is achieved by back-to-back three phase power converters (Generator and Grid Side Converters). A new control strategy named the Active Disturbance Rejection Control (ADRC) is proposed and utilized to control the Wind Energy Conversion (WEC) system based on the SCI-Generator. The objective is to control both the generator and the grid side converters in order to operate the system and to ensure the connection with the power grid. The first converter is used to control the SCI-Generator speed and field to extract the available maximum power from the wind turbine by using a Maximum Power Point Tracking (MPPT) technique and, also, to ensure that the extracted power does not exceed its rated value in case of strong wind speeds; in this case a pitch actuator system is used to control the blades pitch angle of the wind turbine. The second converter is used to control the active and reactive powers injected into the utility grid as well as to regulate the DC-Link Voltage. This control takes into account the rejection of internal disturbances as the variation of electrical parameters (the resistance, the inductance…) and the external disturbances as voltage dips and frequency droops in the main grid. To test and validate the performances of the proposed controller, a series of simulations were developed under MATLAB/Simulink environment, and the results have demonstrated the effectiveness of the proposed control under different case of simulations.

A novel and robust active disturbance rejection control (ADRC) strategy for variable speed wind turbine systems using a doubly fed induction generator (DFIG) is presented in this paper. The DFIG is directly connected to the main utility grid by stator, and its rotor is connected through a back-to-back three phase power converter (AC/DC/AC). Due to the acoustic nature of wind and to ensure capturing maximum energy, a control strategy to extract the available maximum power from the wind turbine by using a maximum power point tracking (MPPT) algorithm is presented. Moreover, a pitch actuator system is used to control the blades’ pitch angle of the wind turbine in order to not exceed the wind turbine rated power value in case of strong wind speeds. Furthermore, the rotor-side converter is used to control the active and reactive powers generated by the DFIG. However, the grid-side converter is used to control the currents injected into the utility grid as well as to regulate the DC-link voltage. This paper aims to study and develop two control strategies for wind turbine system control: classical control by proportional integral (PI) and the proposed linear active disturbance rejection control (LADRC). The main purpose here is to compare and evaluate the dynamical performances and sensitivity of these controllers to the DFIG parameter variation. Therefore, a series of simulations were carried out in the MATLAB/Simulink environment, and the obtained results have shown the effectiveness of the proposed strategy in terms of efficiency, rapidity, and robustness to internal and external disturbances.

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