Nonlinear MPC of kites under varying wind conditions for a new class of large‐scale wind power generators

In this paper we investigate nonlinear model predictive control (NMPC) for control of power generating kites under changing wind conditions. We derive a realistic nonlinear model for a kite and compute energy optimal loops for different wind speeds. We formulate the optimal control problem used by NMPC with an adaptive periodic reference orbit. Under changing wind conditions we use the corresponding energy optimal orbit as reference. To assure that the references do not unnecessarily depend on the wind conditions, we added extra constraints. We solve this NMPC problem numerically with the real-time iteration scheme using direct multiple shooting. Finally, we present numerical simulations which show how this approach can handle even large disturbances of the wind direction and speed with negligible energy losses. Copyright © 2007 John Wiley & Sons, Ltd.

[1]  Moritz Diehl,et al.  Optimal control for power generating kites , 2007, 2007 European Control Conference (ECC).

[2]  M. Canale,et al.  Control of tethered airfoils for a new class of wind energy generator , 2006, Proceedings of the 45th IEEE Conference on Decision and Control.

[3]  H. Bock,et al.  A Multiple Shooting Algorithm for Direct Solution of Optimal Control Problems , 1984 .

[4]  MORITZ DIEHL,et al.  A Real-Time Iteration Scheme for Nonlinear Optimization in Optimal Feedback Control , 2005, SIAM J. Control. Optim..

[5]  Johannes P. Schlöder,et al.  Combined NMPC and MHE for a copolymerization process , 2006 .

[6]  Jay H. Lee,et al.  Constrained linear state estimation - a moving horizon approach , 2001, Autom..

[7]  Moritz Diehl,et al.  Efficient NMPC of unstable periodic systems using approximate infinite horizon closed loop costing , 2004, Annu. Rev. Control..

[8]  M. L. Loyd.  Crosswind kite power , 1980 .

[9]  Johannes P. Schlöder,et al.  An efficient multiple shooting based reduced SQP strategy for large-scale dynamic process optimization. Part 1: theoretical aspects , 2003, Comput. Chem. Eng..

[10]  Johannes P. Schlöder,et al.  Schnelle Algorithmen für die Zustands- und Parameterschätzung auf bewegten Horizonten (Fast Algorithms for State and Parameter Estimation on Moving Horizons) , 2006, Autom..

[11]  M. Diehl,et al.  Optimal Control of Towing Kites , 2006, Proceedings of the 45th IEEE Conference on Decision and Control.

[12]  Moritz Diehl,et al.  Real-Time Optimization for Large Scale Nonlinear Processes , 2001 .

[13]  M. L. Loyd,et al.  Crosswind kite power (for large-scale wind power production) , 1980 .

[14]  F. Allgower,et al.  State Estimation for Repetitive Processes Using Iteratively Improving Moving Horizon Observers , 2005, Proceedings of the 44th IEEE Conference on Decision and Control.

[15]  Johannes P. Schlöder,et al.  An efficient multiple shooting based reduced SQP strategy for large-scale dynamic process optimization: Part II: Software aspects and applications , 2003, Comput. Chem. Eng..