Dynamic Analysis of Rotor and Machine Structure in Ultra-High-Speed PMSM

This paper presents a comprehensive dynamic analysis of a 15 kW ultra-high-speed permanent magnet synchronous motor (HSPMSM) operating at 100,000 r/min.An equivalent bearing modelling method is proposed to effectively simplify and enhance computational accuracy.The intrinsic frequency and vibration characteristics of the motor under both free and operational modes are examined using Finite Element Method (FEM), and the validity of this modelling method is confirmed experimentally.Additionally, frictional and frictionless rotor contact scenarios are comparatively analysed to determine modelling accuracy across a wide range of rotational speeds.Using Campbell diagrams, the critical speeds of the rotor are identified, and resonance phenomena are analysed by the superposition method to establish a safety factor.Experimental verification under various operational conditions demonstrates that the frictional contact modelling provides superior accuracy, particularly at higher rotational speeds.The insights and methodologies presented in this study provide valuable guidance for the mechanical design, modelling, and safe operation of ultra-high-speed PMSMs.