الفهرس 
CHAPTER 1 Introduction 1Only 14 pages are availabe for public view
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Abstract
Wind energy has a rapid growth rate in the electricity market. A considerable share of electricity in many countries is provided by wind power. Wind energy conversion systems (WECS) necessitate continuous monitoring and control to capture the maximum possible output power with wind speed variations. Classical cascaded control structures with linear proportional-integral (PI) controllers have been widely applied for an accurate control of power converters in wind turbine (WT) systems. However, these classical control methods present several drawbacks such as slow dynamic response and highly dependency on tuning of many PI controller parameters. The modulation scheme is an essential tool to control the power converters. Different advanced control schemes are implemented to overcome these issues and enhance the system performance. One of the most suitable advanced control techniques for the power converter control is the finite-control-set model predictive control (FCS-MPC).
This thesis proposes a cascade-free model predictive speed control (MPSC) strategy in variable-speed WT (VSWT) system with a direct-driven permanent magnet synchronous generator (PMSG). The proposed control strategy allows controlling both electrical and mechanical variables simultaneously in a single control loop. The suggested control approach is designed using a hybrid maximum power point tracking (MPPT) technique. Consequently, the classical cascaded structure of PI controllers is eliminated, which enhances the system dynamic response. The suggested MPSC is a model-based control method, its performance is also evaluated under variations of the PMSG parameters. Moreover, a model predictive current control (MPCC) is applied to the grid-side converter (GSC) for active and reactive power control.
A Matlab/Simulink software package is used to implement the complete model of the VSWT system with direct-driven PMSG. The system performance using the suggested control schemes is assessed and compared with the PI speed controller. The theoretical analysis and simulation results demonstrated that the proposed MPSC method outperforms the PI controller in handling system dynamics. Furthermore, the proposed MPSC showed very good performance under PMSG parameters variations.