Traction drives with induction motors are widely applied to railway vehicles. Microprocessor control of such drives makes it possible to achieve any TE-v curve traction characteristic curve (traction characteristic curve, tractive effort-speed curve,) of rail vehicles powered by these drives. The TE-v curve of a particular vehicle depends in practice on the train resistance characteristic as a function of the vehicle speed. In this article, there were described the two control regions of the force-speed curve or torque-speed curve of the induction traction motor, for the stator voltage frequency lower and higher than the rated frequency of the motor. On the one hand, the decrease in the pullout torque with decreasing stator voltage frequency was considered. To maintain the constant pullout torque in the region of lower frequencies, one must take into account a significant increase in stator currents drawn by the traction motor at low frequencies. It may cause the necessity of applying traction converters for larger currents compared to those occurring at the operating point at the rated frequency. On the other hand, the occurrence of the weakened power region (the high speed region) on the TE-v curve was considered. In this region, the maximum tractive effort increases with squared vehicle speed. Merits and drawbacks of TE-v curves of particular vehicles were discussed considering the differences in train resistance characteristics. The increase in the initial value of the train resistance at starting was taken into account by the authors. As it was proved by comparing TE-v curves of various rail vehicles, the problem of increase in the initial value of train resistance has little significance in the case of EMUs and passenger trains hauled by a locomotive but it has great significance in the case of heavy cargo trains and articulated high-speed trains. In this case, this phenomenon cannot be neglected. To analyze correctly performance of particular trains, it should be revealed and shown the phenomenon of an increase in the values of initial train resistance on the curves of train resistance. Some rolling-stock manufacturers show these phenomena. This rule should be accepted as good practice by all rolling-stock manufacturers.
Comparative characteristics of induction motor traction drives for electric railway vehicles
2014
8 Seiten, Bilder, Tabellen, 10 Quellen
Conference paper
English
Electric railway traction. Part 1: Electric traction and DC traction motor drives
IET Digital Library Archive | 1994
|Induction motor drives for traction application
Tema Archive | 1993
|Characteristics of traction motor drives
Engineering Index Backfile | 1944
Torque control of A.C. induction motor traction drives
Tema Archive | 1987
|