Research On Maximum Power Point Tracking Control Of Wind Turbine System

Nowadays, wind power generation technology has become a multi-disciplinary comprehensive high technology system engineering, it involves disciplines including aerodynamic, mechanical, electrical, automatic control, mechanics, materials science, etc. The characteristics of wind power is stochastic, instability, wind energy captures not only associated with the mechanical characteristics of wind turbine, but also to the control methods. If you want to improve the operation stability, and reliability of the turbine and the wind energy utilization coefficient, the key lies in how to choose an optimal control method. Nowadays, the study of control strategy for the variable speed constant frequency wind turbine on maximum point power tracking (MPPT) has become one of the hottest topics in research area.The study of the status of wind power generation technology at home and abroad and the development direction are investigated, and it points out the importance of the research on the technology for wind turbine control, it is studied in this dissertation the widely applied scheme of variable speed constant frequency electric implementation. Because of Doubly-Fed Induction Generator (DFIG) system is easy to control, and the structure is simple, it has become the most studied at present, the most widely used of variable-speed wind power generation system. The mathematical model of DFIG is studied as well as the relationship of the power extracted and the operation modes, laid the theoretical foundation for the study of MPPT control.During the study, the analysis and comparison were investigated for MPPT control strategies of DFIG, and the control algorithm was chosen as the tip speed ratio control. In tip speed ratio of a wind turbine power characteristic curve and the best known circumstances, to measure the speed of the wind turbine, then according to the optimal tip speed ratio under the condition of the maximum power curve to calculate the corresponding maximum output power, as the given value of the output power of the wind machine to control the speed of the wind turbine, in order to realize the maximum power point of capture. Based on the motor with vector control technology, is proposed based on the doubly-fed induction generator stator flux vector control technology, and the methods used in the concrete realization of maximum wind power tracking control. This strategy because they don't need to detect wind speed, and the algorithm is relatively simple, so it has good feasibility.In this study, PI control was adopted which is widely applied in many control systems, it is suitable for large hysteresis characteristics, big inertia of the controlled object, its application in MPPT control of wind turbine systems can reduce wind disturbance effect on the performance of wind turbine dynamics.In this dissertation, Matlab/Simulink was used to build simulation model of the wind turbine, as well as the realization of the simulation platform of control system. For variable speed constant frequency wind power generation system of MPPT control for the change in wind speed and dynamic simulation to the simulation experiment, it is concluded that the reference data to verify the rationality and feasibility of the control systems.