Optimal Trajectories for Tethered Kite Mounted on a Vertical Axis Generator

Tethered kite technology promises the enable the efficient extraction of energy from high altitude winds. One possible concept for converting the wind energy into electricity is to generate useful work at the ground by using a tether. The tether is able to drive a generator in one of two ways: either the tether is wound and unwound, or the tether is attached to a lever arm that creates a torque on the generator. The latter concept, which uses a vertical axis generator, is explored in this paper. A simplified dynamic model of the system is used to optimize the kite motion to give the maximum power generated per operating cycle. The results show that the average optimal power generated per cycle is proportional to the kite area and the cube of the wind speed. Experimental results of a remotely controlled kite are also briefly reviewed.