Simulation And Analysis Of Traction System Of High-speed Trains Based On Permanent Magnet Synchronous Motors

Traction system is the key unit for high-speed trains. Permanent magnet synchronous motors (PMSM) have many advantages such as high efficiency, high power factor, and strong overload capability when used as traction motors in high-speed trains. This thesis focuses on the traction system of high-speed trains based on PMSMs. The control of PMSMs and physical model of traction system are simulated and analyzed. Then the possibility of application of synchronization control techniques in traction motors is discussed.Based on the mathematical model of PMSM, id=0 and maximum torque per Ampere (MTPA) vector control strategies are introduced. Simulation models of id=0 and three different MTPA control methods are built in Lab VIEW. Results show that MTPA strategy is more suitable for PMSMs.Physical model of train traction process is introduced. Based on single PMSM control model, simulation model of traction process is built. Based on this model, the effects of some factors on traction process are analyzed such as adhesion coefficient variations, diameter differences of wheels and parameter differences of motors. Results show that adhesion coefficient variation can lead to slipping, while differences of wheels’ diameters and motors’ parameters have little effect on traction system based on PMSMs.Synchronization control algorithms are introduced. Simulation models of relative coupling control and electronic virtual line shafting (EVLS) control are built. Simulation results are compared and analyzed. Simulation indicates that under given conditions, EVLS control has its limits while relative coupling control works well. After applying relative coupling control to the traction model, effect of adhesion coefficient variation is discussed. Results show that synchronization control has a certain effect of restraining slipping.