A New Transformerless Topology for AC-Fed Traction Vehicles Using Multi-Star Induction Motors

Abstract

SummaryConventional traction vehicles for a.c.-mains contain a line-transformer in the propulsion chain. This transformer, especially for 15 kV/16.7 Hz main lines, is bulky, expensive and has high losses. This paper proposes a completely new transformerless configuration which reduces weight and dimensions of the drive power chain and improves the efficiency. On the line side, series connected voltage source inverters are directly connected via a line choke to the overhead line. This leads to d.c.-links on different voltage potentials, which ask for a new motor concept. The proposed 3-star induction motor with three independent 3-phase windings is fed by three 3-phase inverters on different voltage potentials. A new control structure for this 3-star induction motor becomes necessary and is proposed.Keywords: TractionLocomotivesElectric vehiclesDrivesMultilevel convertersInduction motors Additional informationNotes on contributorsM. SteinerMichael Steiner was born 1963 in Hemer, Germany, after receiving the electrical engineering degree from University of Wuppertal, he joined ABB Corporate Research in Heidelberg, Germany, went 1994 on a job rotation to ABB Verkehrssytem Switzerland From 1995 on he was partly with adtranz., where he is working as a Technology Manager for propulsion system. In 2000 he received His PHD degree from the swiss Federal Institute of Technology (ETH) in Zurich. Working fields Propulsion technology Frequncy Topology, Medium Frequency Topologyies – Transformerless Topology, Medium Frequency Topology, Soft Switching and Alternative Drives And Energy Storage.R. DeplazesRomeo Deplazes was born 1970 in Rabius GR, Switzerland. In 1995 he received his degree in electrical engineering from the Swiss Federal Institute of Technology (ETH) in Zurich with a Transformerless Topologies for Traction Applications using Multi-Star Induction Motors. Since late 1999 he is working with Schindler Lifts Ltd in the department for Technology Management as a Technology and Knowledge Manager.H. StemmlerHerbert Stemnder is Professor for power electronics at the Swiss federal Institute of the Power Electronics and Electrometrology Laboratory. From 1961 up to 1991 he continuously worked with Brown Boveri. & Co., respectively Asea Brown Bovery, in Baden (Switzerland), after 1971 as head of the commissioning and trouble-shooting of power president of this department Working-fields: converter and inverter locomotives, all kinds of large AC-drives, recive power compensator, HVDC-transmission. Low power electronics, standardized and tailor-made electronics control units. Parallel to that, he garguated in 1971 with a doctoral thesis at the Technical University of Aachen (Germany). Since 1991 he is professor for power electronics at the ETH Zürich. At the time there are 11 projects completed by a doctoral thesis and 11 current projects are 11 projects in the field of power electronics (Traction, drives, Flexible AC Transmission System [FACTS], Solar energy system, Uninteruptable power supply, Matrix converter and fuell cell vechicles).