Effect of wheel polygonization on the dynamic response of the electromechanical coupling system in a permanent magnet direct-drive locomotive

The polygonization of railway vehicle wheelsets is a common type of fault that poses risks to the safety and stability of the vehicle. In permanent magnet direct drive locomotives, the rotations of the wheelsets are directly driven by the traction motor; thus, the abnormal vibration caused by the polygonal wheel can directly transmit to the traction system, resulting in strong electromechanical coupling vibrations. To investigate the effect of wheel polygonization on the dynamic response of the electromechanical coupling system in direct-drive locomotives, a locomotive-track coupled dynamic model is established in this paper. The unique structure of the direct drive traction system, the interaction of the wheel-rail system, as well as the electromechanical coupling path of the traction motor are comprehensively considered. Simulation results revealed that polygonal wheels can significantly amplify vibrations in the key components of the traction system; distinct frequencies related to polygons are observed in the electrical signals. Furthermore, the influence laws of wave depth and order of polygonal wear on the dynamic performance of the locomotive components are revealed. These research findings provide theoretical references for health monitoring and operation maintenance of wheel polygonization in permanent magnet direct drive locomotives.