Reserch On Power And Load Control Technology Of Doubly-fed Wind Turbine

Due to the disadvantages of conventional energy sources,human beings has been paid more and more attention to renewable energy.Wind power is one of the fastest growing renewable energy sources because of its mature technology and excellent flexibility.However,due to the height of the Wind Turbine Generators(WTG),the increase of the diameter of wind mill and the expansion of the sweep area of the fan,the load of the wind turbine is more complicated and more heavy.This will directly affect the WTG’s output power smoothness and operating life.In order to improve the efficiency of wind energy utilization,it is possible to reduce the load of the unit itself,prolong the service life of the WTG,reduce the cost of operation and maintenance,and have good prospects in industrial application.In this paper,the variable speed pitch control technology of double-fed WTG under full wind speed is studied.The aerodynamic model of WTG and the control process of maximum wind energy tracking are also given.The control model of double-fed WTG and Independent pitch control(IPC)system was explored.In order to alleviate the unbalanced load that occurred in operation above rated wind speed in large WTG and the fluctuant power of the WTG under the gust.This paper focuses on the independent pitch control(IPC)technology of the doubly-fed WTG.Firstly,the aerodynamic theory and load situation of WTG are introduced,including the source of wind turbine and how to calculate load,and the load of the blades under the influence of wind shear,tower shadow and turbulence by means of simulation analysis.The characteristics of the unbalanced load of WTG running at high wind speed and its influence on the WTG output power and WTG service life are described in detail.Secondly,the principle and process of WTG power control are analyzed,including the control model of doubly-fed WTG power system.In this paper,the 2MW doubly-fed WTG is modeled and simulated in Matlab/Simulink,and the MPPT control system of doubly-fed WTG is described in detail.Finally,the IPC strategy of the doubly-fed WTG is studied.Establishing the IPC scheme based on Coleman coordinate transformation and proposing an IPC control strategy based on Ant Colony Algorithm(ACA).The proposed control strategy is verified by the means of FAST and Matlab/Simulink simulation.The simulation and experimental results show that the IPC based on ACA-PID is effective and practical,it can improve the dynamic performance of the control system,effectively reduce load imbalance and improve the vibrational state of the WTG.