Research On Maximum Wind Power Tracking Control Of Variable-speed Constant-frequency Doubly-fed Wind Power Generation System

The aggravation of the global climate and the decrease of fossil energy had led to anincreasing attention to the development and utilizing of the new energy in many countries. Asa kind of renewable and clean energy, wind energy has been an large proportion in the newenergy because of its rich, wide and clean. Wind power has the mature power generationtechnology and considerable development scale. The two advantages bring it a favorablemarket outlook. Since the variable-speed constant-frequency wind energy system is usedwidely, improving the efficiency of wind energy and realizing the maximization of outputpower have been a matter of concern.This thesis has focused on realizing the maximum power tracking for variable-speedconstant-frequency wind energy system. The development situation of wind power and therelated technology of wind power firstly have been summarized, as well as the research statusof maximum wind energy tracking technology. While this thesis has a detailed analysis for themechanism of wind turbine, the characteristics of wind power generation system and thetheories and control methods of maximum power tracking with the basic theories of wholewind energy system. Then, the mathematical models have been established at differentcoordinates according of the characteristics of doubly-fed induction generator. Since the statorflux oriented vector control is used to the power control of generator, this paper has builtdouble closed-loop generator control system which contains speed outer loop and current innerloop. On this basis, this thesis proposes a maximum power point tracking algorithm with fuzzycontrol. It combines the characteristics of optimal power curve and improved hill climbingmethod with fuzzy control, and it can track the maximum wind energy according of the bestrotor speed for different wind speed given by the designed fuzzy controllers. The algorithmdose not require wind speed measurement or related parameters and models of wind turbine,and it has a simple control method and a good robustness. The Simulation results confirm thatthis algorithm can be well combined with generator vector control and has a good effect intracking the maximum power in random wind condition.