| Energy is one of the important material basis for human survival and development.In the process of social progress,resources are increasingly depleted,at the same time,climate,ecological and environmental problems are caused by a long-term use of coal,oil,natural gas and other fossil resources are worse.Wind energy as a clean and development technology is relatively mature renewable energy,has broad prospects for development.At present,direct drive permanent magnet synchronous wind power generation system has been widely used because of its simple drive system,reliable operation,high power efficiency and so on.First of all,the mathematical model of direct drive permanent magnet synchronous wind power generation system is established,and the operation principle and vector control strategy of direct drive permanent magnet synchronous wind power generation system are analyzed.Due to the power loss of the system,the traditional maximum wind energy tracking control strategy based on power feedback cannot be given the accurate maximum power in the practical application,which can affect the efficiency of the system.In this paper,considering the copper loss,iron loss,mechanical loss and stray loss in the permanent magnet synchronous wind generator model,calculating the value of the loss,based on the traditional power feedback control,studying the maximum wind energy tracking control is given the best current considered loss torque,so as to improve the wind energy capture efficiency.Secondly,due to the wind power generation system is a complex system with multi variable,nonlinear,strong coupling,time-varying;it is difficult to establish an accurate mathematical model.This paper uses the variation of the pitch angle as the output of the fuzzy controller,designs a variable pitch controller based on the fuzzy control theory has a strong anti-interference ability.Considering the actual pitch actuator has delayed action.At the same time the speed of the variable pitch is limited,when the wind speed comprises a gust of wind or high-frequency changes,only adjusting the pitch angle of the wind turbine is difficult to achieve the expected effect,wind generator output power and rotating speed of the unit still fluctuates significantly.By using the traditional active power control strategy,the output power of the wind power generator can fluctuate,which has a large disturbance to the safe and stable operation of the power grid.So,the active power smoothing control strategy is proposed,which combines the variable pitch control and variable speed control of wind turbines in the full range of wind speed.Finally,the simulation model of the direct drive permanent magnet synchronous windpower generation system is established on the Matlab/Simulink platform,which verifies the effectiveness and correctness of the control strategy. |
