Design construction of a 2 kW Laddermill groundstation

摘要

This paper presents the design & construction of a 2 kW Laddermill groundstation. The Laddermill is a novel concept to harvest electricity from high altitude winds. The concept's operating principle is to drive a generator with kites. Several kites are high in the air at an altitude of more than 1 km. All kites are connected to a single cable that connects to a drum in the groundstation. The lower part of the cable is connected to the kites and is wound around a drum. The kites pull the rope from the drum, which in turn drives a generator. When all of the cable is pulled off the drum, the kites fly down in a configuration that generates significantly less lift than during the ascent. This way the lower part of the tether is retrieved onto the drum and the process is repeated. The concept allows very large single unit power. At Delft University of Technology, a 2 kW test model of the Laddermill was constructed and tested successfully. This paper will present the groundstation that was used for the 2 kW Laddermill. It is mounted on a trailer and generates DC power at 24V, into batteries that are also on the trailer. The 2 kW groundstation was a test model for a larger, 100 kW groundstation that will be built in the coming year. The 2 kW version has several shortcomings which should be eliminated in the design of the 100 kW test model. These shortcomings are discussed and solutions for the larger groundstation are proposed. Furthermore, preliminary results of the first Laddermill energy production are presented.