Investigation of dynamic and synchronization properties of a multi-motor driving system: Theoretical analysis and experiment

•An electromechanical coupling dynamic model of the MDS is established.•Use the proposed model to analyze dynamic and synchronization characteristics.•Dynamic and synchronizing properties are studied by simulation and experiment.•Running status and synchronizing status of the system can be reflected by current. The multi-motor driving system (MDS) is a typical electromechanical system that is widely used in electric vehicles, aerospace, marine engineering, and other fields. The dynamic and synchronization properties of the MDS are affected by both the mechanical and electric subsystems. Generally, the load and speed of the MDS is time-varying. Therefore, this paper presents an electromechanical coupling dynamic model of MDS that can reflect the characteristics of MDS under time-varying load and speed conditions. Based on the developed model, the dynamic and synchronization properties of MDS are investigated under three typical conditions. Meanwhile, a series of experiments are conducted for comparison with the theoretical analysis. The theoretical and experimental results demonstrate that the current can be used to monitor the torque and its synchronization, and reflect the vibration characteristics of the MDS. The components of response frequency of the current signal do not change with the speed of MDS, but the amplitudes of the response frequency change with the system speed. Similarly, this phenomenon can also be observed in the spectra of the torque, speed, and vibration acceleration signal.