Research On Vector Control Of Doubly-Fed Wind Power Generator

Now, energy sources consume increasing daily and environment empoison being serious gradually, in the exploitation for the renewable energy source, wind power is paid great attention by more and more countries because of its outstanding excellence. The wind power generation technology also becomes research hotspot of many countries' scholars. And the variable-speed constant-frequency(VSCF) generation technology is paid attention more and more for its high efficiency and practicability. VSCF operation uses doubly-fed generator working principle. When wind speed changes, the constant-frequency output can be generated from the stator side, by connecting with low frequency excitation current at the rotor side, its frequency, amplitude and phase angle is controllable.In this paper, the relative fledged doubly-fed generator in wind energy application technology in the day is researched on vector control. Vector control is one of the advanced theories, which is based on motor unification principle, energy conversion and vector coordinate transformation theory. It has many advantages such as novelty, practicability and advancement.Firstly, the basic principle of variable speed wind turbine generators is introduced. According to the variable speed wind turbine operating in different regions, the basic control strategy is set out. After the analysis of its structure and its VSCF electricity generating principle, the mathematic model of all section of VSCF double-fed wind power generation system on two-phase synchronous rotation coordinate is build.Secondly, the stator field-oriented vector control method for the control of the doubly-fed generator is used. Using vector control technology, a doubly-fed generator independent of the active and reactive power control is achieved. A concise form of the equation and easily control program are achieved, which found the effective theory for the further studies.Finally, a control system of doubly-fed VSCF wind power generator based on DSP is researched in accordance with the characteristic of control system. This paper depicts a general hardware structure of system and control programmed frame respectively. It provides the key hardware circuit diagram and the flow chart of control programmer, and their work principles are described. The simulation results are given to verify the strategy by the stator field-oriented vector control.