| Countries in the world on the road of rapid development of industrialization. With the gradual depletion of fossil energy and the increasing environmental problems caused by the massive consumption of fossil fuels, which have become two major problems that puzzled us, thus there is only one choice for humanity, that is, the transformation of energy, and the development of renewable clean energy. Wind energy as a form of energy without any pollution that got fully developed, which has a special significance to solve the energy problem of the world. Since 21 st century, the global vigorously develop the wind power industry, the total installed capacity of wind power continuous rise and the technology of wind power also generate new. With the continuous expansion of the capacity of single machine, it has always been a hot issue in the field of wind power technology about how to use wind energy effectively and improve the power generation efficiency of the unit, furthermore, the impact of large capacity generating units on the grid connected to the power grid can not be ignored, so the grid connected technology of wind power generator has become a research focus in the field of wind power technology.Doubly fed wind generator unit is the mainstream model of wind farm at present, its characteristic is to realize variable speed constant frequency operation, and the capacity of the current transformer is only the unit capacity 1/3, which compared to the full power current transformer unit can greatly reduce the cost. This paper mainly makes a research on some problems of this model.According to the wind turbine’s actual running data and found the actual sending power to less than ideal conditions, in order to improve the efficiency of the wind turbine, this paper the control system for in-depth study and optimization is put forward.This paper briefly introduced the control principle of maximum wind energy capture, which was through analyze the power loss of the maximum wind capture influence, for doubly fed wind power generator considering the power loss that proposed the maximum power point tracking(MPPT) control strategy. The mathematical model of the doubly fed induction generator(DFIG) considering the iron losses in the two-phase d-q rotating coordinate system was derived, and set up the whole simulation model of double fed wind generator in SIMULINK. By comparing and analyzing the simulation waveforms under the maximum power tracking control strategy that considering the power loss and without considering the power loss, which was concluded that the wind turbine can be operated in the optimum power speed curve when the power loss was considered, and achieved the conclusion of maximum wind energy capture. In order to solve the problem of DFIG model with no load running in simulation software, this paper also derived the mathematical model of no-load operation of the doubly fed wind generator which was in the two-phase d-q rotating coordinate system, and the same built in the simulation software, which was used for the simulation research of no-load grid connected control strategy of doubly fed generator load and verified the correctness of the mode by simulation and theoretical analysis of this model based on.The experimental platform of wind turbine generator driven by directcurrent motor was set up,mainly included:IPM driver circuit、IPM peripheral protection circuit、 detection and modulation circuit、zero crossing detection circuit、rotary encoder detecting circuit、fault signal processing circuit、grid connected device, and detailedly introduced the working principle and function of each circuit. With DSPF2812 as the controlling core, written the control procedures of double fed generator on CCS3.3, which mainly included the main program and each function subroutine. Then debugged the program on the hardware platform. Finally, through the analysis of the experimental results, it is proved that the theory proposed in this paper is correct. |
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