Research On Maximum Wind Energy Capture Of Variable Speed Constant Frequency Doubly-fed Wind Power Generation System

Energy is the material foundation of social progress and human history progress,but the traditional energy is limited,how to reasonably develop new energy to replace fossil fuels and solve the environmental pollution caused by burning coal is urgent.At the same time,consistent with the sustainable development strategy,it is an important way to solve the energy crisis.How to use modern power electronic devices to achieve maximum capture of wind energy and reduce the cost of wind power generation.In this paper,the structure of doubly-fed wind power generation system is analyzed,and the maximum capture of wind energy is realized by double closed-loop control design on generator side and power network side.The main contents are as follows: First of all,the double PWM control structure of doubly-fed wind power generation system is analyzed,which can be controlled separately by DC link,and the mathematical model is established by deducing the related mathematical formula.The control structure of generator side converter and grid side converter is analyzed by adding feed forward compensation voltage.Secondly,the optimal tip ratio method,power feedback method and mountain climbing search method are introduced to realize the maximum wind energy capture control strategy.The advantages and disadvantages of various control strategies are summarized and an improved control strategy is put forward.The best tip ratio method requires a high accuracy of wind speed measuring instrument,which will increase the economic cost.The power feedback method does not need the wind speed measuring instrument,but needs to set the actual power to carry on the feedback correction(namely according to the generator output power and the wind turbine sends out the power feedback to carry on the control.Mountain climbing search method does not need speed and power sensor,so it is more practical in the simulation test;the traditional mountain climbing search method has too long fixed step setting will affect the search efficiency,too short will be oscillating at the maximum power point;The improved variable step size control strategy is used to speed up the response time of the system,and fuzzy control is combined to reduce the jitter of the maximum power point of the system,and to increase the accuracy of the system.Finally,the paper uses particle swarm optimization algorithm(PSO)and fuzzy adaptive control strategy to realize maximum wind energy capture,and simulates it in MATLAB/Simulink software,and compares it with improved power feedback fuzzy control.The results show that this strategy can achieve maximum wind energy capture and maximum wind energy capture under low wind speed.PSO algorithm can improve the system parameter setting time,enhance the adaptability of power feedback link and increase robustness.It is feasible.