Future Power Electronics Applications for Railway Vehicle Traction

Railways are able to couple many large cars and run them at speeds of hundreds of kilometers per hour due to being supported (support), guided (turning), and driven (running/ stopping) by steel rail and wheel systems. Much energy is thus needed to move railway rolling stock. Railways initially utilized steam locomotives, but use of electric energy started in the early 20th century, and that soon came to be applied to railways as well. This probably came about because much electricity could be transmitted easily by overhead contact lines and pantograph systems, even with the technology of the time, as routes of travel could be secured with high accuracy as a result of the direction of travel being restricted by rails and wheels. In other words, because railway rolling stock is a steel rail and wheel system, just the amount of electricity needed could be supplied when needed, large but light rolling stock achieved, and high-speed/high-volume transport with high energy efficiency achieved. On the other hand, the route traveled can be selected freely with automobiles, so they need to be autonomous in terms of energy. For that reason, a system where fossil fuel is stored onboard and the vehicle is driven by an internal combustion engine developed. However, automobiles too came to run on electricity again in the 21st century. Technology at the dawn of the age of the automobile where batteries and motors could sufficiently compete against notyet-mature internal combustion engine technology. Also, the history of the advancement of electric railways and the recent trend of electrification of automobiles demonstrate that electric drive systems are technically superior. In order for electric drive systems to be feasible, technology to convert electric energy to mechanical energy is naturally needed. With electric railways, the devices and functions to achieve that are collectively called traction circuit systems. In traction circuit systems up to now, direct current electric motor drive systems advancing to low-maintenance and highly efficient alternating current electric motor drive systems and improving their performance were focused on. As a result, traction circuit devices were able to achieve high efficiency, high performance, and high functionality. However, there is little room left recently for improving on traction circuit system technology alone. In technology for energy saving, for example, it is thought that the need is growing for considering technology for energy saving from a perspective of controlling a train’s operating energy, such as utilizing regenerative energy or considering the operating method of the train itself. Also, with the advance in technology behind power storage accompanying electrification of automobiles, there have been movements to apply this to railway rolling stock driving as well. This suggests that the time has come to reconsider the how energy is supplied to rolling stock too, such as the aforementioned assumptions of electric driving.


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  • Accession Number: 01605824
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 25 2016 2:00PM