الفهرس 
1 INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. Recently, modern wind turbines are the fastest growing and most cost-effective renewable energy technology in the world. The usage of wind turbine generators is increasing, especially where customers are environmentally conscious. Wind turbine aerodynamics remains a challenging and crucial research area for wind energy. Clearly, steady-state aerodynamic performance is essential to turbine energy capture, since blade aerodynamic forces produce mechanical energy that is subsequently converted to electrical energy. However, more recent inquiry has focused on adverse time varying aerodynamic loads that wind turbines frequently suffer during routine service. As many wind turbines are installed offshore, a non-planned service can be highly costly, so it would be beneficial if an active fault tolerant control schemes could help the turbines produce energy from the time a fault is detected to the next planned service. Furthermore, the implementation of fault diagnosis schemes entails operational benefits due to its feature of early detection of faults, which can make the wind turbine operate safer and reduce costs as a result of possible improved maintenance procedures. Therefore, fault diagnosis and fault-tolerant control of wind turbines may offer several benefits. The major benefit is focused on preventing catastrophic faults deteriorating the operational individual parts of the considered wind turbine by early fault diagnosis and accommodation. Additionally, it reduces the expensive maintenance costs through eliminating the obligatory replacement of individual functional parts by utilizing condition-based maintenance instead of time-based maintenance. It also provides the most up-to-date diagnostic details to the competent maintenance staff as well as keeping energy production when a fault has occurred by means of fault-tolerant control. This thesis adopts an integrated active fault tolerant control system design relies on a fault detection and diagnosis (FDD) process to monitor system performance, detect abnormal conditions through residuals generation algorithm, isolate the faulty
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component in the modern wind turbine and estimates the effectiveness factor relating to the detected fault. A model-based fault detection and diagnosis technique is developed with deeper insight into the process behavior using a reconfigurable extended Kalman filter estimators due to the non-linear nature of the wind turbine benchmark model. Accordingly, a systematic approach to an on-line reconfigurable LPV-based fault-tolerant control system combined with signal correction algorithm is proposed to accommodate faults which either change the dynamics of the wind turbine or reduce the available measurement sensor information. A comparison between the developed active LPV-based fault-tolerant control scheme and the robust passive LPV-based fault-tolerant control scheme is accomplished for the relevant faults. The effectiveness of the proposed fault diagnosis and fault tolerant control scheme has justified by simulation result on the benchmark model of variable-speed, variable-pitch 4.8 MW horizontal axis wind turbine with simulated actuator and sensor fault scenarios. Simulation results in both nominal and fault scenarios emphasize that the proposed control reconfiguration approach can compensate faults and control the turbine quite well in both nominal and fault situations.