The Studies On The Control Technology And Operating Characteristics Of Variable Speed Constant Frequency Doubly Fed Wind Power Generation System

As we all know, the energy crisis and environmental crisis that is plaguing the world's development, so wind power and other new energy development and utilization is being more and more attention. As a green clean energy, wind energy development and utilization is of great significance. Therefore, the emphasis on countries in the world and the race to develop wind power technology is becoming increasingly in-depth and maturity. Currently, variable pulp from VSCF wind power generation technology is the world's main trend of wind power generation. however, AC excitation double-fed induction wind power generation system because of it's efficiency and cost advantage is being widely used. It has been widely made use of in the variable-speed constant frequency wind power generation system. This topic is against this background of the double-fed induction wind power system operation and control of carried out analysis and research. The main contents are as follows:Firstly, this paper discusses the status of the development of wind power generation technology, studies the doubly-fed motor working principle and advantages, and establishes a mathematical model of doubly-fed motor. Its operating characteristics and power relations in a theoretical analysis laid the theoretical basis for the full-text research. Secondly, commonly used generator excitation mode is analized. Through the double-fed motor three-phase static coordinate system and the two-phase rotating coordinate system the mathematical model for analysis, field-oriented vector control technology is applied to the double-fed motor operation control, and a stator flux-oriented vector-based control strategy is formed, and the generator active power and reactive power decoupling control are realized. In the study of the double-fed motor rotor excitation power, the characteristics of dual-PWM converter is analyzed.Between similarities and differences about machine-side converter and nerwork-side converter in function and control are introduced. It is important that network-side converter control method in base of grid voltage-oriented vector control technology is introduced and control block diagram and mathematical model as to nerwork-side converter of voltage and current double closed loop control is established to realize unity power fact control in net side converter AC-side and DC Voltage control. In base of introducing the characteristics of wind turbine,the principle of largest wind power tracking is analyzed and the program of implementation on the use of double-fed machine to achieve maximum wind power control tracking is determined.Finally, network-side PWM converter is analyzed by using of Matlab/simulink simulation software. The results show that it can be well positioned to meet the needs of the exchange of excitation power generation system. At the same time, the entire power system simulation model is built.The wind speed and the system power grid voltage dips are both simulated and analyzed. In the control strategy, Double-fed wind power generation system realizes the DC bus voltage tracking for a given value, the stator voltage output constant frequency and voltage, active power and reactive power decoupling control, and the largest wind energy tracking. Then, it verifies the correctness of the overall model and the feasible of control strategy.