Induction instead of overhead wires
Anyone who frequently uses trains knows this to be true: overhead lines are prone to faults, increasingly leading to delays and cancellations. An alternative to this is energy transmission without overhead lines.
In the framework of the Allianz DLR@Uni-Stuttgart, scientists from two institutes at the University of Stuttgart as well as the German Aerospace Centre (DLR) are researching inductive (contact-free) systems that are to replace the overhead lines one day.
For this purpose the State of Baden-Württemberg has set aside 860,000 Euros. “With these funds the state government is supporting the researchers at DLR and the University of Stuttgart in exploiting the enormous potentials of contact-free energy transmission for fewer noise emissions, less wear and tear and maintenance work and less energy consumption“, explained the Finance and Economy Minister Nils Schmid on the occasion of the presentation of the research report. As the next step the scientists want to develop a demonstrator that will undoubtedly also be of interest for the industry.
Overhead lines for electrically operated railroad vehicles are exposed to the weather and other environmental influences that could lead to a high degree of wear and tear and pose a risk for the environment in the case of damage. In addition the lines and pantographs are a significant source of noise and the high aerodynamic air resistance has a significant impact on the energy consumption.
Induction instead of overhead lines is therefore the goal of the project for which the DLR Institute for Vehicle Concepts has joined forces with the Institutes of Electrical Energy Conversion (IEW) and Machine Elements (IMA, railroad vehicle technology and reliability technology divisions) at the University of Stuttgart. The scientists are thereby relying on a principle according to which electric cars and trams can already be charged contact-free with limited transmission power.
Its mode of operation corresponds to that of a sliced transformer, whereby the primary coil is integrated in the drive and the secondary coil is located in the vehicle. The energy transfer is done via a generated magnetic field and is possible over the complete length of the vehicle on a large scale. In this respect each part segment of long trains with a distributed driving power can be supplied separately with energy without an elaborate energy supply line through the vehicle being necessary. Through this each carriage that has its own drive can for example be moved autonomously in the shunting area.
Whilst the IMA dedicated itself in particular to the mechanical design and the integration of the new components in the vehicle as well as the reliability and availability of the energy transfer, the IEW was particularly involved with the design of the energy transfer system as well as the supply electronics and the electrical components. No wear and tear, less susceptibility to faults and as high an efficiency factor as possible (over 90 percent) and also with far more efficiency were thereby of primary interest. Moreover, attention was paid to maintaining a downward compatibility with existing rail systems as far as possible and to continuing to improve train control systems.
“The inductive energy transfer developed in this interdisciplinary project enables an efficient and robust supply of railroad vehicles with electrical energy“, is how Prof. Johann-Dietrich Wörner, Chairman of the Board of the German Aerospace Centre (DLR) expressed it. An essential viewpoint is that the railroad vehicles through a hybrid energy supply can be driven on new routes as well as on the existing railroad network.“
Prof. Bernd Bertsche, University of Stuttgart, Institute for Machine Elements, Reliability Technology Division, Tel.: 0711/685-66165, Email: bernd.bertsche (at) ima.uni-stuttgart.de
Prof. Dieter Bögle, University of Stuttgart, Institute for Machine Elements, Railroad Vehicle Technology Division, Tel. 0711/685-66098, Email: dieter.boegle (at) ima.uni-stuttgart.de
Prof. Nejila Parspour, University of Stuttgart, Institute of Electrical Energy Conversion, Tel.:0711/685-67818, Email: nejila.parspours (at) iew.uni-stuttart.de
Dr. Joachim Winter, DLR-Institute for Vehicle Concepts, Project Manager of the project “Energy transfer without overhead lines“, Tel: 0711/6862-274, Email: joachim.winter (at) dlr.de.
Andrea Mayer-Grenu | idw - Informationsdienst Wissenschaft
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