Rotation Speed and Wind Speed Indirect Measurement Methods for the Control of Windmills with Fixed Blades Turbine

The implementation complexity of classical algorithms for wind turbines control limits the utilization of low-end microcontrollers for such applications. We conceived an original method that aims to optimize the efficiency of windmills with fixed blades with the variation of the wind speed. In the paper we present an original method to determine generator's efficiency values using measurements that were performed at the prototype's homologation, along with original simplified models of wind turbine and of wind turbine - generator assembly. Measured values of the frequency, voltage and current of the generator are applied to determine the turbine rotation speed and the wind speed, reducing thus the number of needed sensors. A couple of families of regression functions were derived and tuned accordingly to the factory experimental characteristics to allow for a facile calculation of the generator's efficiency database table. To further speedup the assessment of the optimum /safety value of the windmill rotation speed, the generator's model is considered to provide the rotation as a function of the wind speed in a tabular format that is further used at run-time as a look-table for rapid interpolations in the control loop. The main advantages of the proposed approach are the simplicity and robustness of the implementation, being easily portable to low-end microcontroller platforms.