Manufacturing Tolerance Sensitivity Analysis on Performance and NVH characteristics of an Axial Flux Machine in YASA design

Inhalt:
This paper presents sensitivity analyses of geometrical tolerances for a Yokeless and Segmented Armature (YASA) design Axial Flux Machine (AFM) for electric vehicle applications. Geometrical tolerances like glue thicknesses, inhomogeneous air gaps or displacements between the two rotors influence the peak performance, efficiency and noise, vibration and harshness (NVH) behaviour of electric motors, where torque ripple amplitudes and tooth forces are critical factors. For the investigated 12-pole 18-slots AFM, uniformly tolerances in a variation range of 10% as well as a Gaussian distribution considering realistic tolerance ranges at selected operating points are used. Due to the high computational effort for three-dimensional (3D) finite element (FE) simulations, a multiple slice linear motor approach is used to perform further sensitivity analyses with 2D FE simulations. Even though the accuracy of the 2D FE results is limited due to the lack of interaction between the individual slices and the insufficient representation of three-dimensional effects, the ranking of the most sensitive parameters remains consistent between 2D and 3D FE simulations. This compromise leads to a significant reduction in simulation time, with different numbers of simulations being used to determine single parameter sensitivities and cross sensitivities highly.