Integration improvement of dfig-based wind turbine into the electrical grid

Résumé

Resumen de la tesis: This doctoral thesis in electrical engineering is presented as five research works linked together by the same theme. Five articles were published in indexed journals. In this sense, each of these works forms a piece of the puzzle constructed around the subject ” wind farms integration into the electricity grid.” To better understand the articulation between these works, this thesis is structured in three parts: The first part treats the Fault Ride Through (FRT) capability of the Grid-connected DFIG-based Wind Turbine. The first proposed approach is a hybrid method combining two methods (active and passive methods): The active method aims to develop the control of DFIG. In con- trast, the passive method is applied for severe voltage faults using hardware protection circuits. Otherwise, the second proposed approach is a control design implemented to the power converters using Proportional- Resonant regulators in a stationary two-phase (α − β) reference frame. The control performance is significantly validated by applying the real-time simulation for the rotor side converter and the hardware in the loop simulation technic for the experiment part of the generator’s grid side converter control. This thesis’s second part presents a new fault diagnosis and fault-tolerant control strategy for doubly fed induction generator with DC output based on predictive torque control. Generally, the current sensor failures can deteriorate the reliability and the performance of the control system and can lead to the malfunction of the predictive control strategy since the rotor- and stator flux cannot be estimated correctly. The proposed fault diagnosis can deal with all types of sensor faults. A non-linear observer adapted to the studied system to achieve smooth operation continuity when two or all the current sensors are faulty. The proposed approach’s feasibility and robustness are achieved by testing different sensor faults on the stator- and rotor- current and under different operation mode cases. The third part focuses on calculating the wind capacity credit by integrating the Moroccan project on the wind energy of 1000 MW in 2020. After introducing the Moroccan Integrated Wind Energy Project, a wind capacity credit assessment program will be implemented on Matlab software, including the complete information about ”installed capacity, number of plants, failure rate, types of installed units, peak demand, etc.” This program will be used to calculate the safety rate of an electrical system as well as the capacity credit of Morocco’s electricity production network. The research provides conclusions according to comments and assessment of the impact of this electric energy integration based on wind generation. http://repositorio.bib.upct.es/dspace/