Modeling and nonlinear model predictive control of kite system for high altitude wind energy generation

Kitenergy is an emerging technology in airborne wind energy (AWE) that captures high altitude wind energy (HAWE) by exploiting its controlled flight of tethered wings. Compared with its ground level counterparts, AWE has the advantages to harness wind energy with a higher efficiency and a more consistent behavior. Automatic control of the kite's airfoils is crucial to the proper running of kitenergy systems. In this paper, a control oriented model of a tethered kite system is developed step by step, and a simplified state-space model is established as a first attempt. Based on this model, a nonlinear model predictive controller (NMPC) is designed to track a pre-optimized figure-eight trajectory. The merits of the NMPC are validated by simulation studies on a practical-scale kitenergy system model.