Research On Excitation Control Technology Of Doubly-fed Wind Power Generation

With the development of the wind power generation technologies in China, the level of the manufacture for wind generation system, the electric equipment design and mechanicals are very closed to or reached international one, but the core control technologies influencing on electric energy quality and wind-electricity transforming efficiency, has confined us in the area of development for wind generation system industry and is a bottle-neck on fully independent intellectual property rights. With the core technology of excitation control, variable speed constant frequency doubly-fed wind power generation system is widely applied as its outstanding advantages, so excitation control technology is the hotspot in the field of wind-electricity.An excitation control method, which combines intelligent control (variable universe fuzzy control) with vector control, is adopted for the application on the doubly-fed wind power generation system.Firstly, after analyzing the principal theory of variable speed constant frequency doubly-fed wind power generation system, the stator flux orientated control method and coordinate transform are adopted in this thesis to build the decouple model in which the active power and reactive power related to excitation current and voltage of the system are included, and this made the foundation for system design and simulation experiment.Secondly, a set experimental platform of doubly-fed wind generation system is designed. The issues of traditional PID control and general fuzzy control are analysed, due to doubly-fed wind power generation system is a complex system with nonlinear, strong coupling, severely affected by parameters varying and external interferences, and variable universal fuzzy control is adopted in this thesis, to design a doubly-fed wind power generation excitation control system with high performance. Two closed loop control is adopted in this controller, variable universe fuzzy control is used in the outer loop whose set value is power and PI control is used in the inner loop whose set value is current, and then the dynamic performance and control precision is promoted. Finally, the control system is simulated under different parameters in Matlab/Simulink environment. The results show that variable universe fuzzy controller not only can realize control for doubly-fed wind power generation system, also promote dynamic performance and self-adaptive capability.