Sensitivity analysis for induction machine manufacturing tolerances in EV and HEV

Production processes of induction machines suffer from manufacturing tolerances because of assembly imperfections. This causes undesired deviations in the machine´s performance and behavior. In particular, the equivalent circuit parameters of the machine are affected. Therefore, the validity of the electrical parameters of a reference machine is doubtful for sample machines. In this work, a sensitivity analysis by design of experiments is carried out over the whole torque-speed characteristic map. This analysis is done in order to investigate the influence of design variables (e.g. airgap) on the electrical parameters. The aim is to show the importance of paying an attention to the deviations of parameters resulting from tolerances, to identify how the parameter deviation trend is, and which geometrical parameters have the most significant impact on the machine parameters. The study is done using finite element method for an induction machine for electric vehicles by changing the design variables in the tolerance band. Analysis results show that a mathematical model, that describes the deviations of electrical parameters, can be extracted.