Research Of Variable Pitch Control In Variable Speed Wind Turbine System

In recent years, directly drive wind power system(D-PMSG), due to its high efficiency, easy manufacture and good control performance, is becoming the focus of research. Because of the randomness of the wind energy and the aerodynamic effect, the direct drive wind power system has the same feature with conventional wind power systems, that is strongly nonlinear, fast dynamic process, so the traditional control method is difficult to achieve high-precision control. Thus there is very important significance in introducing advanced control theory to control globally.Directly driven wind power system is mainly composed of two parts:wind turbine and multi-polar permanent magnet synchronous generator (PMSG),this paper mainly research the modeling and control of the two parts:First of all, through analysis the mechanism and operation characteristics of the wind turbine and PMSG,get the mathematical model,then modeling in the Matlab/Simulink simulation environment; Secondly, based on the research of feedback linearization theory, presents its application in the direct drive wind power system,get the two part linear model; Then, according to the two linear model,use the optimal control method to achieve the target at two different wind speed:when the wind speed above rated wind speed, the PMSG achieve the maximum power point by adjusting the rotational speed of the rotor;when the wind speed is higher than the rated wind speed, wind turbine part realize rated power output by adjusting the pitch angle.Finally, this paper design the controller,realize the simulation by Matlab/Simulink,compare and analyze the results with PID control, verify that the proposed control strategy is correct and superior.