Large-Scale Reverse Pumping for Rigid-Wing Airborne Wind Energy Systems

divAccording to both scientific papers and sector studies, airborne wind energy systems (AWESs) have the potentialto provide large-scale, sustainable, and economically viable electricity production. In this work, we consider a pumping AWES with arigid wing and vertical takeoff and landing (VTOL) capability withonboard propellers. In fully autonomous operation, the system mustbe able to handle the complete wind range from cut-in to cut-out. Incase of too low wind speeds for a relatively short time or if the poweroutput needs to be curtailed following possible grid operatorcommands, the system shall be able to switch to astandby mode,wherethe kite remains airborne until the wind increases again or the poweroutput is increased again. In the literature, there are a few studies on such an operational mode, which is referred to asreverse pumping,and none on the design of a feedback control system that is ableto obtain reliably a large-scale reverse pumping maneuver.The main contribution of this paper is a hierarchical, automaticcontrol approach to achieve reverse pumping operation for AWESwith a tether length of the order of hundreds of meters while at thesame time being relatively easy to implement and tune./div