Virtual Evaluation of Stator Failure Modes using Multiphysics Analysis Approach

The modern luxurious electric vehicle (EV) demands high torque and high-speed requirements with increased range. Fulfilling these requirements gives rise to the need for increased electric current supply to motors. Increased amperage through the stator causes higher copper loss resulting in high temperature generation across the motor components and its casing. In most of the cases. stator is mounted on the casing through interference fit to avoid any slippage during operation conditions. High temperature across the stator and casing causes significant thermal expansions of the components which is uneven in nature due to the differences in corresponding coefficient of thermal expansion (CTE) values. Casings are generally made of aluminium and tends to expand more having higher value of CTE than that of steel core of stator which may give rise to a failure mode related to stator slippage. In this paper, we are exploring the effect of high amperage through the hairpin with the help of a coupled electro-thermal analysis. The spatial temperature distribution obtained through this analysis is imported into a thermos-structural analysis to obtain the deflection and stress developed within the stator components and casing. Predicted deflection can give an insight into the slippage failure mode at the stator-casing interface. Additionally, the durability of different stator components can also be evaluated subjected to the amperage fluctuation during operation conditions. Hence, the simulation methodology described in this paper can be used as a decision-making tool in the initial design phases to avoid any slippage and durability related failure modes of stator components.