Sensorless real-time reduced order model-based adaptive maximum power tracking pitch controller for grid connected wind turbines

Abstract

To overcome the mechanical stress and damage caused by the high wind speed and grid transient on the wind turbine (WT) and to ensure the smooth operation of WT, a sensorless maximum power tracking (MPT) pitch controller for grid integrated WT is proposed in this paper. The advantages of the proposed controller are: a) reduced rotor speed oscillations, b) reduced transients in Point of Common Coupling (PCC) voltage, and c) controlled output power of WT without exceeding its thermal limits. The controller is validated on the WT integrated into the frequency-dependent reduced order model (FDROM) of the power grid. Another advantage is that, as the reference speed for the controller is estimated using FDROM, actual wind speed measurements are not required in this approach. To ensure smooth operation, and to limit the aerodynamic power and speed within the normal operating range, the difference between the actual and reference speed of the generator is used as the input to the controller. The architecture is validated using a real-time digital simulator (RTDS) on WT integrated two-area and IEEE-39 bus power system models. The simulation results show that the proposed controller is more effective than the conventional methods during changing system operating conditions.