Investigation of electromechanical coupling torsional vibration and stability in a high-speed permanent magnet synchronous motor driven system

•Electromagnetic excitation was derived by using Maxwell theory.•The electromechanical coupled mechanism was revealed based on the natural frequency modulation.•The nonlinear torsional equation and mechanism were validated by experimental results.•Some analytical resonance characteristics were investigated and confirmed by numerical studies. A permanent magnet synchronous motor (PMSM) driven system is a typical electromechanically coupled system. In this paper, to improve the operational performance and stability of the PMSM system, torsional vibrations due to the electromechanical coupling effects are studied. An electromagnetic excitation model was first established to consider the effect of torsional angle on magnetomotive force. Then, nonlinear torsional vibration equations of the driven system were obtained. In addition, an electromechanically-coupled torsional vibration mechanism based on natural frequency modulation of the system was revealed. Finally, the torsional vibration equations and coupled mechanism were validated against experimental results describing the actual torsional vibration and a numerical method was used to verify our theoretical analysis. The results provide a theoretical basis for the parameter design of electromechanical transmission systems.