Non-Axisymmetric Structural Analysis of High Speed Rotor Orthotropic Retention Sleeve

Abstract

This paper presents an analytical model for the structural analysis of orthotropic rotor retention sleeves of High-Speed Surface mounted Permanent Magnet Synchronous Machines (SPMSMs). The solutions herein derived generalize existing analytical models for non-axisymmetric geometries, considering orthotropic materials (e.g. Fiber Reinforced Polymers). These rotor geometries arise when pole gaps are present, i.e. magnetically inert regions between rotor poles. This design feature allows magnet material savings, reduction in eddy current losses and overall mass minimization during the machine optimization. The results were validated using Finite Element Analysis (FEA). The analytical model described is approximately 400 times faster to compute than FEA. This is particularly advantageous for machine design optimization using evolutionary algorithms, which require a large number of design evaluations.