Identification of a discrete-time piecewise affine model of a pitch-controlled wind turbine

In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is identified in the vicinity of the optimal wind turbine static characteristics. The aerodynamic rotor torque and thrust force of a 1 MW wind turbine are identified as piecewise affine static functions of wind speed, rotor speed and pitch angle using the clustering-based technique. These static functions are post-processed to rule out irregularities induced by the identification procedure and are then incorporated in a dynamic model of the wind turbine. The resulting model, that consists of 29 affine dynamics, is verified against the starting nonlinear model of the wind turbine and very good agreement with that model is obtained. The identified discrete-time piecewise affine model will be used in synthesis of optimal control laws for improving power production and reducing fatigue loads of the wind turbine.

[1]  O. Mangasarian,et al.  Multicategory discrimination via linear programming , 1994 .

[2]  Ervin Bossanyi,et al.  Wind Energy Handbook , 2001 .

[3]  Manfred Morari,et al.  A clustering technique for the identification of piecewise affine systems , 2001, Autom..

[4]  G. Ziegler Lectures on Polytopes , 1994 .

[5]  N. Peric,et al.  Piecewise affine identification of MIMO processes , 2006, 2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control.

[6]  Richard O. Duda,et al.  Pattern classification and scene analysis , 1974, A Wiley-Interscience publication.

[7]  Alberto Bemporad,et al.  Dynamic programming for constrained optimal control of discrete-time linear hybrid systems , 2005, Autom..

[8]  Leo Breiman,et al.  Hinging hyperplanes for regression, classification, and function approximation , 1993, IEEE Trans. Inf. Theory.

[9]  Marko Bacic,et al.  Model predictive control , 2003 .