Research On Maximum Power Point Tracking Control System Of Wind Turbine

This thesis focuses on the problem of maximum power point tracking for achieving the maximum wind energy tracking of variable speed wind turbine power generation systems at low wind speed. Power electronic converters and maximum power point tracking strategys in wind generator systems provide the basic platform to accomplish the research of this thesis.In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Variable speed wind turbine,permanent magnet generator,three-phase AC-DC-DC-AC converter as well as transformer, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Three-phase AC-DC-DC-AC converter is used to deliver the energy generated by permanent magnet generator to the utility grid. Furthermore , as the important section of DC link to deliver power of energy in the converter system, double Sepic converter as well as Sepic converter are introduced and specifically analyzed in this thesis.An advanced maximum power point tracking strategy of a variable-speed wind energy conversion system which is expected to work well, relies not only on the converter topology which is adopted by wind energy system, but also on the control mode of its own. Based on the study of normal maximum power point tracking strategys, a novel maximum power point tracking strategy is presented in this thesis, which estimates the operating point of the turbine according to the variations of the system's output power,stored energy and speed and thus the wind speed and the characters of wind turbine are not required.Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and validating the feasibility of the maximum power point tracking strategy. So the variable speed wind power generation systems studied in this thesis are modeled using Matlab/Simulink. The simulation results adequately confirm the validity and feasibility of the maximum power point tracking strategy which is presented in this thesis.