A nonlinear wind velocity observer for a small wind energy system

In this paper a nonlinear strategy is presented to estimate the wind velocity in a small variable speed wind energy system. The approach is based on a nonlinear state observer considering the rotational speed and electrical variables as the measured ones. The observer is based on a general nonlinear model of the wind turbine characteristic and an assumed wind variation model. This approach is simple and does not require a complex searching algorithm to find the estimates. In addition, the convergence of the estimates can also be analyzed using standard tools. Results of wind velocity estimation using realistic wind profile, representing some wind conditions in the world most southern city of Punta Arenas, demonstrate the performance of the proposed approach.