Energy efficiency enhancement of wind energy conversion systems with MPPT control

Renewable energy-based power generation systems can be a solution to the increasing energy demand and the problems that arise regarding conventional energy sources. The use of the wind energy, which has a serious potential among these sources, has been growing rapidly and gaining popularity worldwide thanks to the developing technology in recent years. Wind Energy Conversion System (WECS) generates energy through certain transformation stages. Extracting the maximum power from WECS more effectively and thus improving the energy efficiency is one of the most important research topics. Although traditional methods have been used in literature and industrial applications at this point, there are also requirements for more effective and innovative control strategies and algorithms. In this thesis study, the issue of capturing both maximum mechanical power and maximum electrical power from permanent magnet synchronous generator based WECS with power conversion topology including uncontrolled rectifier and DC-DC boost converter is discussed in detail. Various Maximum Power Point Tracking (MPPT) algorithms have been used to determine the optimum operating point for the system to operate at maximum power and also different type sliding mode controllers that have not been adapted before from this point of view have been designed to bring the system to this point. In addition to these, it has been worked on integrating current optimization techniques into MPPT methods. Two hybrid unified maximum power extraction frameworks, which combine separately two derivatives of chaotic-based particle swarm optimization with the optimum relation-based method and adopt a controller based on sliding mode control theory, have been derived as well. All tests on designed various wind speed change profiles have been verified in the simulation environment and stability analyzes for controllers are also presented in detail. In consequence of all these studies, it has been observed that the MPPT system efficiency is contributed by more accurate and precise determination of the maximum power point as well as achieving a superior tracking performance with less steady-state error and voltage fluctuation.