Dynamic performance of locomotive electric drive system under excitation from gear transmission and wheel-rail interaction

Abstract

Development of railway transportation capabilities towards high-power, high-speed and heavy axle-load makes the dynamic interactions between the electric drive subsystem and the mechanical subsystem of a locomotive more intensive and complicated, which may threaten the locomotive operational safety. However, the included dynamics mechanism and influencing law have not been revealed completely. Based on the co-simulation method and vehicle-track coupling dynamics, a model which enables considering dynamic interactions between the electric drive subsystem and the mechanical subsystem of a locomotive through an electromagnetic coupling interface and motor control subsystem is developed in this paper. By using this co-simulation model, the dynamic responses of the mechanical subsystem and the electric drive subsystem are analysed under complicated dynamic excitation, such as the time-varying gear mesh stiffness and the track geometric irregularity. The results indicate an obvious interaction between the electric drive subsystem and the mechanical subsystem, where the vibration status of the major mechanical components can be reflected by the electric current signals. Besides, the characteristic frequencies of the gear transmission can be extracted from the frequency spectrum of the traction motor current signals, which provides the possibility for condition monitoring and fault diagnosis of the locomotive mechanical components through the electrical signals.