Design Of The Wind Power Physics Simulation System Based On Micro-Grid Connection

With energy and environmental crises is aggravating, wind power generation, especially the new energy technology gets more and more attention. Variable speed constant frequency(VSCF) doubly-fed wind power generation technology has been applied in many places as its advantages of higher energy utilization efficiency and lower converter capacity. It is necessary to establish VSCF doubly-fed wind power physical simulation system in the laboratory, as the actual wind experiment research is expensive and time-consuming.Firstly, based on the analysis of the working principle and characteristic of the wind turbine and doubly-fed generator, this paper simulates the output characteristic of wind turbine by the asynchronous motor. Then control strategy of microgrid-connection with no load is formulated to realize flexible grid-connection of wind power system.At last, the doubly-fed wind power simulation system is builded which can provide the theoretical and experimental basis for further research on wind power and microgrid tecnology.Wind power is a complicated process, the wind speed model must be established to simulate the characterastics of the wind turbine, the mathmatical model of wind speed is established through the algorithm method in this paper. The wind speed is simulated by four kinds of components. Several wind speed curves can be got from the simulation of the four kinds of components combinations under different conditions in the MATLAB/Simulink software.The wind speed model is proved to be correcet by comparison of the natural wind speed simulation and the actual wind speed curve.According to the wind speed model,wind power calculation principle and Betz theory, we can get the relation between the wind turbine output torque and rotor speed, namely the wind turbine output characteristic curve. By the analysis of the working processes in the wind power system during the wind speed changes, the wind turbine simulation principle is clear and definite. Asynchronous motor vector control method is choosed to simulate the wind turbine output characteristics by comparison of two methods of wind turbine simlation.Doubly-fed machine has been applied in many places as its many advantages. In this paper, the working principle and characteristics of doubly-fed induction motor are introduced. The mathematical model of the doubly-fed induction motor in the three-phase static coordinate is established. By using a series of coordinate transformation, mathematical model of the doubly-fed induction motor in the synchronization coordinate is worked out. Base on the mathematical model of motor in the synchronization coordinate and principle of stator voltage orientation, the control strategy of microgrid-connection with no load is formulated to realize flexible grid-connection of wind power system. The simulation analysis of mathematical motor model and control strategy of microgrid-connection with no load is verified by the experiment, and the results are ideal.At last, wind power simulation system based on Siemens man-machine interface and S7-300 series programmable logic controller (PLC) is accomplished. This system has the function of monitoring equipment status, simulation of wind power system, storaging and analyzing experiment data, user management and fault alarm. It also provides the theoretical and experimental basis for further research on wind power and microgrid tecnology.