الفهرس 
Wind turbine technology
WECS modelingOnly 14 pages are availabe for public view
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Abstract
As a result of the circumstance that the generation of power is low when compared to consumers demands; Wind Energy Conversion System (WECS) is playing an important role in minimizing that difference. WECS extracts the energy available in the wind and converts it into electrical energy. The development of control systems for WECS interconnecting grid has become a significant topic in the scientific research. Grid stability and WECS protection are the most important aspects of grid interconnection.
Using Permanent Magnet Synchronous Generator (PMSG) for variable speed wind turbines based on matrix converter (MC) has many advantages compared to other variable speed wind system approaches. The MC connects PMSG directly to the grid. However, this configuration has complex operation principles and control. This thesis presents a current controlled matrix converter to interface PMSG based WECS with the grid. A complete third order model for the PMSG is developed in the d-q synchronous reference frame. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG current to extract the maximum power from the wind at a given wind velocity and to inject reactive power to the grid. The main challenges of WECS are to maximize the energy capture from the wind and to offer a Low Voltage Ride Through (LVRT) capability.
Furthermore, this thesis proposes an improved, fast dynamic control system for PMSG speed using optimal tuning of Proportional Integral (PI) controller. Bacterial Foraging Optimization (BFO) technique is employed because of its ease of implement, short execution time and robust mechanism of escaping from local optimum. The active current component of PMSG is controlled by improved PI controller, which is tuned using BFO algorithm, to deliver maximum power from the turbine to the grid. The proposed control system has the ability to control both active and reactive PMSG current components to extract the maximum power from the wind turbine. In addition, the proposed controller has the ability to inject reactive power to the grid at normal and fault conditions according to grid code requirements. A dynamic limiter is employed to control the grid reactive power during faults at the range of matrix converter rated current.
A STATic synchronous COMpensator (STATCOM) is controlled as a mean to support grid voltage stability by offering a compensation of reactive as well as active power compensation. STATCOM with ultracapacitors as an energy storage element is developed with wind turbine. The proposed control system for the STATCOM is responsible for smoothing the output power from the proposed WECS.
The proposed WECS has been modeled and simulated using PSCAD/EMTDC software package. In addition, the BFO algorithm is built on MATLAB. The dynamic performance of the proposed controllers is evaluated under different wind speeds. The simulation results of the system prove validity of the proposed controller for both steady and dynamic conditions. In addition, the LVRT capability of the proposed WECS is tested. The results prove the success of the proposed control system in satisfying the grid code standard.