Anti-slip control of traction motor of rail vehicles

Abstract

Railway transport is becoming an increasingly preferable transportation system worldwide. Due to the demand and emerging technologies in the railway sector, more powerful rail vehicles are produced. The recent development in power capacity of the vehicles enables them reaching high torques in a short time. On the other hand, the traction ability of these vehicles is limited by environmental conditions (i.e. rain, snow, leaves and mud) and human influences. Because of the mentioned reasons, wheel slip becomes one of the most important factors influencing the safety, traction performance and lifetime of the rail vehicles. Hence, this work deals with the use of anti-slip control methods for rail vehicles. Initially, to give readers a general picture of the research covered in the thesis, the adhesion and slip mechanism are explained. Furthermore, the slip detection methods and slip control methods based on the literature review are introduced. To verify the validity of the anti-slip control schemes, a numerical model of a tram wheel roller rig that includes nonlinear effects caused by time delay and disturbances to match the values of the experimental test setup has been generated using MATLAB editor. The provided numerical model consists of a PMSM, an AM, a wheel, a roller and two drive shafts. Freibauer and Polach adhesion force model has been employed to determine the coefficient of adhesion and adhesion force taking place between the wheel-roller. Five wheel slip control strategies -wheel slip control based on single threshold (WSCST), wheel slip control based on multiple thresholds (WSCMT), wheel slip control based on angular acceleration of wheel (WSCAA), PI wheel slip control (PI-WSC), and sliding mode wheel slip control (SM-WSC)- are suggested. In addition to the simulation calculations, this work includes an experimental part in which extensive experiments are carried out on laboratory test equipment where the anti-slip algorithms are implemented and tested. The validity of the developed numerical model is proven with the comparison of the simulation and experimental results. The performances of all the wheel slip control methods are evaluated through the mathematical model and experimental setup. The influences of different roller speeds and control parameters are analysed via validated numeric model.