Feedback linearization control of constant output power for variable pitch wind turbine
变桨距风力发电机组恒功率反馈线性化控制

When the wind speed exceeds the rated value, the wind power captured by the wind turbine must be reduced to guarantee the wind turbine to operate in the safe and stable status. A control scheme for limiting the power of the variable pitch wind turbine based on the differential geometry feedback linearized theory is proposed to keep the rotational speed and output power at the rated value. An affine nonlinear model of the wind turbine is developed and then globally exactly linearized by a differential geometry transformation. With the new linearized model, we design a novel pitch angle controller in which the output feedback variable is the rotational speed and the input control variable is the blade pitch angle. When the wind speed exceeds the rated value, the pitch angle controller changes the blade pitch angle to reduce the rotational speed back to the rated value for ensuring the constant output power. Simulation results show that, when the wind speed is above the rated value, the proposed control strategy effectively implements the constant output power control for the variable pitch wind turbine with fine flexibility and robustness.