Vibration Study of Axial Flux Permanent Magnet Motor Base on Static Eccentricity Model

The axial flux permanent magnet (AFPM) motor has become a strong contender for electric drive systems for its compactness, high torque density and high efficiency. In the manufacturing process of motors, errors between the stator and rotor are unavoidable and cause large noise and vibration problems during the operation of the motor. Notably, motor vibration plays a key role as a critical metric for evaluating advanced electric drive systems. To explore the effect of manufacturing errors on AFPM vibration, this paper first analyzes the different error types of AFPM motors. Then a theoretical model based on the error analysis is developed to study the spatial and temporal orders of the axial electromagnetic force. Finally, a finite element model is developed for the yokeless and segmented armature (YASA) motor boasting 20 poles and 24 slots, allowing for a comparative assessment of the axial electromagnetic force characteristics in the absence and presence of diverse forms of manufacturing errors. The results show that the difference in the amplitude of the electromagnetic force is highly dependent on the manifestation of specific errors generated during the motor manufacturing process. These errors help to amplify the amplitude of the oscillations of the lower-order forces, thus exacerbating the vibration and noise of the motor.