Analytical method to compute bridge stresses in V-shape IPMs

Abstract

V-shape interior permanent-magnet machines (IPMs) have been widely utilised in the industry due to their high-power density, high efficiency, and low manufacturing cost. There has been growing interest in applying multi-objective optimisation to the design of electric machines. In the context of V-shape IPM designs, it is important to include stress analysis in the optimisation design analysis as the steel bridges in the IPM rotor are structural weak points, where high stresses develop. However, traditional finite element analysis (FEA) that is normally used to compute bridge stresses becomes cumbersome due to its high computational cost. In this study, a computationally efficient analytical method is proposed to compute the mechanical stresses developed within the steel bridges in a V-shape IPM. The proposed method is shown to yield accurate predictions compared with FEA while reducing computational cost. A design study is conducted that demonstrates that the machine performance can be improved by incorporating the proposed structural analysis in a multi-objective optimisation-based-design environment.