In Refs. [8 e 11 ] the authors used artificial neural networks to estimate the wind speed directly. However, in those solutions, the node parameters (the weight vector included) need to be calculated off-line with an extensive set of input vectors. In some real-time
conditions the output of these estimators can be inaccurate, specially when these conditions were not included in the training input vectors. Also, in some operating points the estimators can give wrong estimations of the wind speed [9].