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In order to increase the efficiency, to ensure availability and to prevent unexpected failures of the doubly fed induction generator (DFIG), widely used in speed variable wind turbine (SVWT), a model based approach is proposed for diagnosing stator and rotor winding and current sensors faults in the generator. In this study, the Extended Kalman Filter (EKF) is used as state and parameter estimation method for this model based diagnosis approach. The generator windings faults and current instruments defects are modelled, detected and isolated with the use of the faults indicators called residuals, which are obtained based on the EKF observer. The mathematical model of DFIG for both healthy and faulty operating conditions is implemented in Matlab/Simulink software. The obtained simulation results demonstrate the effectiveness of the proposed technique for diagnosis and quantification of the faults under study.

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This chapter presents the modeling and simulation results of variable speed wind turbine driven by doubly fed induction generator (DFIG). The feeding of the generator is ensured through its stator directly connected to the electrical grid and by its rotor connected to the grid through two power converters, which are controlled by the pulse width modulation (PWM) technique. This configuration is the most used in the wind power generation systems. For the variable speed operation of the studied system, the maximum power point tracking strategy is applied for the turbine, and the stator flux-oriented vector control is used for the generator. The MATLAB/Simulink software is used for the system modeling and simulation. For the wind velocity model, a random wind profile is simulated, and the turbine and the generator parameters are extracted from an existing wind turbine system in the literature. The obtained results are addressed in this chapter.

In this article, we have proposed a new control of a PV system connected to the grid. The goal is to reduce current and voltage harmonicsfor increasing the quality of delivered energy. First, we have modeled a PV panel. Then we have dimensioned the BOOST converter by finding L and C values. Next, we have used Perturb and Observe (P&O) Maximum Power Point Control (MPPT) to improve energy efficiency. Finally, We have developed a control of single-phase H-bridge inverter in order to eliminate the 3 rd ,5 th ,7 th and 9th harmonics order, and added an LCLTo connect the PV inverter to the grid, an LCL betweenthe inverter and the grid. Theperformance of the proposed system was tested by computing spectrum and THD usingMatlab/Simulink software. The proposed architecture provides better Total Harmonic Distortion (THD) which satisfy the EN50160 requirement the THD must be less than 4.66%. We found that THD was decreased from 61.93% to 0.04%.