The Research On The Control Technology Of Variable Speed Constant Trequency Double Fed Wind Power Gneeration System

Nowadays, the whole world’s development is suffering from the energy crisis aswell as the environmental crisis. Thus, the development and utilization of newenergies has attracted more and more attention. Wind power technology has been paidgreat attention as wind power is a green clean energy resource. Currently, variablepulp from VSCF wind power generation technology has become the world’s maintrend of wind power generation. However, AC excitation double-fed induction windpower generation system is being widely used because of its efficiency and costadvantage. It has been widely made use of in the variable-speed constant frequencywind power generation system. Based on the above mentioned issues, this thesisanalyzed the operation and control of the double-fed induction wind power system.The main contents are as follows:Firstly, based on the trend of development of wind power generator technology,this paper studied operating principle and advantages of the doubly-fed motor, thenestablished a mathematical model of doubly-fed motor to analysis its operatingcharacteristics and power relations. Thus, this paper laid the theoretical basis forfuture research.Secondly, through the excitation mode of commonly used generator, and thedouble-fed motor three-phase static coordinate system, the two-oriented vector-basedcontrol strategy is formed, thus the decoupling control of generator’s active powerand reactive power could be realized. Then, this thesis made a comparative studyabout functions and control methods of the machine-side converter and network-sideconverter, especially the control technology of network-side converter control methodin base of grid voltage-oriented vector.In the next part, After the introduction and analysis of wind turbine’scharacteristics as well as the maximizing tracking range of wind power, the programof implementation on the use of double-fed machine to achieve maximum wind powercontrol tracking is determined.By the same time, this thesis established block diagram and mathematical modelas to network-side converter of voltage and current double closed loop control torealize unity power fact control in net side converter AC-side and DC Voltage control.Finally, a analysis of the network-side PWM converter is performed by using the Matlab/simulink simulation software. The results showed that the needs of theexchange of excitation power generation system can be met. At the same time, theentire power system simulation model is built. The wind speed and the system powergrid voltage dips are both simulated and analyzed. Under all control strategy,Double-fed wind power generation system can realizes the DC bus voltage trackingfor a given value, realizes the stator voltage output constant frequency and voltage,realizes the active power and reactive power decoupling control, and realizes themaximum wind energy tracking. Then, it verifies the correctness of the overall modeland the feasible of control strategy.