The Research Of Variable-pitch Wind Turbine Control Based On Gain Scheduling

The control strategy of Wind turbine have experienced a transition from fixed pitch stallregulated to variable pitch control. Although the way of fixed pitch stall regulated is quite stableand reliable, its work efficiency is very low. With a single wind turbine unit capacity higher andhigher, it’s difficult to achieve the effective control. For MW-level wind turbine, variable pitchcontrol gradually become the mainstream control way, which regulates the pitch of blade in orderto change the attack angle of airflow on the blade. Thus, the aerodynamic torque wind turbineobtained have been changed with the pitch, Such that the output power keeps stable.This paper mainly studies the control strategy for wind turbine. Especially for large variablespeed variable pitch wind turbine, through researching on the control strategy about how toreduce generator speed fluctuation above rated wind speed, it’s found that the pitch angle ofwind turbine changes nonlinearly relative to wind speed. This paper proposes that it couldchange the controller gain reasonably to make controller parameter comply with pitch angle,which could stabilize the operation of the wind turbine.At the same time，a new optimization strategy has been put forward for improving aboveAlgorithm. The specific implementation is to change the generator torque by designing aAppropriate Fuzzy controller, which operate above the rated wind speed. That controller couldmake Generator torque vary with the change of power, so as to inhibit of the rapid rise of thegenerator rotational speed.When conducting the control of generator rotational speed, it’s introduced that the conceptof "virtual speed",which means pitch angle could be responded quickly to the generator speeddeviation. The simulation studies based on Matlab have shown that this control strategy not onlysuppress the speed overshoot effectively, but also could enhance the robustness of the windturbine.