The Research Of The Maximum Power Point Tracking In Small Wind Power Generation System

Under the dual pressures of global ecological deterioration of the environment and the gradual depletionof fossil energy, the research and utilization of new energy has become the focus of attention around the world.In addition to hydroelectric power technology, wind power is the most mature technology as renewable energy,the largest scale of development and the most prospective technology as commercial development of powergeneration. But how to maximize the efficiency of energy and extend the life of the unit are hot issues of windpower.The research significance and background of wind power as well as its domestic and foreign researchstatus are introduced in this paper. Theoretical analysis is studied based on the operating principle of smallgrid-connected wind turbine small wind power system. The structure of small wind power system, and themathematical model of the wind wheel, drive chain, asynchronous motor and converter system is established.According to the basic principle and characteristics of the wind energy conversion system, the workingprinciple of the small-scale wind power generation system with maximum power point tracking strategy isintroduced，and the advantages and disadvantages of the three methods are described as follow: optimal tipspeed ratio method, power feedback method, climbing search method. Base on the step of climbing searchmethod, two variable step strategies are studied: double-step and slope based, and their disadvantage in thesearch of maximum power point.An improved variable step size climbing method is proposed. Improvedclimbing variable step method adopts three sampled values of time and the slope of two adjacent points to getthe searching step and to realize the stop function.Finally, the above four algorithms are simulated in MATLAB. By analyzing the dynamic performanceand steady-state performance of the four algorithms, the improved climbing method has a good effect on themaximum power point tracking of small wind power systems,and not only increased the utilization of windenergy,but also avoided the mechanical oscillations when wind speed is stable.