Current signal characteristics analysis of transmission system in high-speed train under abnormal vibration conditions

Abstract

Abnormal vibration monitoring of high-speed trains is usually performed by analysing the vibration acceleration of specific structures to identify characteristic signals. However, due to the harsh operating environment caused by multiple internal and external sources of compound excitation, vibration monitoring of high-speed trains faces numerous problems, such as easy damage to vibration sensors, limited installation space for testing equipment, and difficulty in vibration testing of rotating parts. This paper takes high-speed train transmission system as the research object, combines multi-body system dynamics and electric transmission control theory to establish an electromechanical model of high-speed train transmission system, and carries out simulation research for three typical working conditions of high-speed train, which are wheel flat, wheel polygon and hunting motion. By analysing the transmission response of wheel–track relationship, gearing and motor current under three operating conditions based on Motor Current Signal Analysis (MCSA), it can be concluded that the motor current signal can be used instead of the vibration signal to identify the above three abnormal operating conditions by analysing the characteristic frequencies in the motor stator current. While MCSA is commonly used to diagnose faults such as tooth surface pitting and tooth root cracking inside gearboxes, the results of this paper show that motor current signals can also be used to monitor any abnormal operating conditions of high-speed trains that can cause changes in motor load torque.