The Solution To The Problem Of Wind Power Grid With High Permeability

Recent years, countries in the world began pay attention to energy problems. With the exploitation and consumption of fossil energy and the emerging environmental problems, clean energy has played an increasingly important role in the development of the society. Wind power, as it can regenerate, is inexhaustible and had no pollution to the environment, has been a top priority of energy in the world. But, because of the stochastic volatility of wind, when wind electricity with high permeability enters power grid, it will obviously influence the stability of power grid. So, how to stabilize the instability power caused by the entering of high permeability wind power into power grid is the focus of the thesis.Firstly introduces the development of wind power at home and abroad, and describes the problems caused by high permeability wind power grid-connection. The volatility of the wind power is the major problem of wind power grid-connection. To smooth the fluctuation of wind power, the thesis combined with the characteristics of accumulator and super capacitor, adopting the method of hybrid energy storage coordination, establishes the model of direct drive wind power system to carry on detailed study of the structure of generator-side rectifier and web side inverter structure of the system, and designed a dual PWM control strategy.Secondly, in order to reasonably control the energy storage system, the thesis studies the structure and operating principle of the bidirectional DC/DC converter, and adopts the double closed loop control strategy of energy storage based on the of the converter. Using the control method can complete two-way transmission of energy, and recover the changing voltage return to normal working condition. Set up the experimental platform of the converter, illustrate the calculation of parameters in the main circuit, design the drive circuit and the sampling circuit, and at the same time write the program.Energy storage grid-connection inverter is the bridge between energy storage system and grid. Analyze the model of energy storage grid inverter, adopt current-type energy storage grid inverter, and through feed forward decoupling and double closed loop control, make the direct current sent out by energy storage system transfer into alternating current(ac) which can be incorporated into the power grid.Finally, apply the hybrid energy storage structure to design the whole system. Based on low-pass filter principle, the wind power fluctuation can be divided into high frequency and low frequency wave power, and allocate them according to the characteristics of the energy storage element. Two kinds of energy storage component control separately and finally connect in parallel in the same grid inverter dc side; the other end of inverter is connected to the electricity grid. The simulation of the above work is carried on in the Matlab/Simulink environment. The simulation result shows that the control strategy is effective and feasible, and wind wave power can be stabilized through this method.