Electromagnetic Vibration Analysis Of Dual-Redundancy Permanent Magnet Synchronous Motors

Permanent magnet motor,especially rare earth permanent magnet motor,it has wide range of applications due to its significant advantages in power density,structure,loss,efficiency and so on.But with the requirements like aerospace,unmanned aerial vehicles,missiles and other high-precision motor areas of higher reliability,dual-redundant technology is being gradually applied to the permanent magnet motor.Similar to traditional permanent magnet synchronous motor,dual-redundancy permanent magnet synchronous motor also has electromagnetic vibration caused by electromagnetic force between the stator and rotor.Radial component of electromagnetic force produces electromagnetic vibration and causes mechanical vibration and mechanical deformation of the stator,tangential component produces electromagnetic torque,outputting mechanical energy.According to the research status of motor’s electromagnetic vibration at home and abroad,this paper takes dual-redundancy permanent magnet synchronous motor with low thermal coupling and non-electromagnetic coupling between windings of each phase(DRPMSM)as a study object.Electromagnetic vibration caused by electromagnetic force was mainly studied,including air gap magnetic field analysis,modal analysis,and transient dynamic analysis.The impact on electromagnetic vibration of small teeth was analyzed by comparing the vibration displacement result of the motor having small teeth with the outcome without teeth.Meanwhile,electromagnetic vibration under a single-redundancy working condition was also researched when the motor had a short-circuit fault.Details are as follows:First,air gap magnetic field and electromagnetic force in DRPMSM were analyzed qualitatively.Permanent magnetic field,armature reaction magnetic field and synthetic magnetic field were analyzed respectively.Radial magnetic flux density and radial electromagnetic force in inner surface of the stator were got by finite element method(FEM),and their harmonic components were obtained using Fourier decomposition.Then,inherent structure modal simulation was done.In addition to radial electromagnetic force,the vibration characteristic of the motor is also an important factor of electromagnetic vibration and noise.Modal parameters are used to describe the structure’s natural vibration characteristics,including mode shapes,natural frequencies and damping ratios.Relationship between modal parameters and electromagnetic vibration of DRPMSM was derived by FEM.At last,established stator’s 2-D structural finite element model of DRPMSM,and transient dynamics simulation was done.The electromagnetic force obtained in electromagnetic field was applied to motor’s structural finite element model,calculated stator’s forced vibration under electromagnetic force to get its vibration characteristics.Besides,the influence of small teeth on the motor’s electromagnetic vibration and the single-redundancy electromagnetic vibration were studied.