Sensorless control of induction machines, in railway applications

Abstract: In this master thesis, a sensorless system has been developed for an induction machine in railway applications. The approach which was taken in this master thesis is a consequence of the expectations of the company: investigate thepossibilities of having the current generation of Alstom's drive system working without use of a speed sensor. Some tests have thus been performed in order to validate parts of this statement. However, because of the substantial time that would require an exhaustive investigation and a complete development, from simulation to tests on a real train, it has been decided to focus more on selecting a method relevant for Alstom's specications, and simulate it in order to identify issues. Thus, from an extensive literature search based on books and articles considered as references, several methods has been investigated and one have been selected for simulation. Two set-ups were used for simulations; one developed in Matlab and the other one using real-time simulators used by Alstom to test and validate its hardware and control software. From these tests, it was showed that for an accurate control, it is necessary to estimate, jointly with the speed, main motor parameters. But these motor parameters can hardly be all estimated at the same time and a strategy in order to estimate eciently these other parameters is proposed. Issues related to a practical implementation are also investigated and some conclusions are drawn for an implementation of a sensorless system in an Alstom train.