Abstract:In this paper a new robust direct torque control strategy based on second order continuous sliding mode and space vector modulation of a doubly fed induction generator integrated in a wind energy conversion system is presented.The conventional direct torque control (C-DTC) with hysteresis regulators has significant flux and torque ripples at steady-state operation and also the switching frequency varies in a wide range. The proposed DTC technique based on second order continuous sliding mode control reduces flux, current, and torque ripples. It also narrows down the switching frequency variations in induction machine control. Two different sliding surfaces such as flux and torque sliding surfaces are used to control them. The error between reference and actual values are driven to respective sliding surfaces where the error is enforced to zero. Simulation results show the effectiveness of the proposed direct torque control strategy comparatively to the C-DTC one.

The vector control (VC) method based on proportional-integral (PI) controllers of a doubly fed induction generator (DFIG) integrated in a counter rotating wind turbine (CRWT) system have many problems, such as low dynamic performances, coupling effect between the d-q axes and weak robustness against variation parametric. In order to resolve these problems, this research work proposes an adaptive backstepping sliding mode (ABSM) controller. The proposed control strategy consists in using dynamic-gains that ensures a better result than a conventional VC method. Stability of the proposed ABSM control approach has been proved by the Lyapunov method. Simulation results depicted in this research paper have confirmed the good usefulness and effectiveness of the proposed ABSM control.

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<span>This article presents an improved Direct Torque Control (DTC) technique with space vector modulation (SVM) for a five-phase permanent magnet synchronous motor (PMSM) using a sliding mode speed control (SMC).The proposed control scheme of the five-phase PMSM combines the advantages of SMC control and the SVM algorithm. The SMC method insensitive to uncertainties, in particular external disturbances and parameter variations. In this paper, the SMC controller is used to control the rotor speed of the five-phase PMSM based on DTC-SVM. The rotor speed response, torque and stator flux are determined and compared with traditional control method. The simulations results confirm the validity and effectiveness of the proposed control technique in terms of performance and robustness against machine parameter variations (inertia variation). The efficiency of the proposed method applied on the five-phase PMSM is verified by the MATLAB/Simulink.</span>

Abstract-This article present a novel direct torque control (DTC) scheme using high order sliding mode (HOSM) and fuzzy logic of a doubly fed induction generator (DFIG) incorporated in a wind turbine system. Conventional direct torque control strategy (C-DTC) using hysteresis controllers presents considerable flux and torque undulations at steady state period. In order to ensure a robust DTC method for the DFIG-rotor side converter and reduce flux and torque ripples, a second order sliding mode (SOSM) technique based on super twisting algorithm and fuzzy logic is used in this paper. Simulation results show the efficiency of the proposed method of control especially on the quality of the provided power comparatively to a C-DTC.