Finite Element Modeling and Analysis of a Three-Phase Induction Motor Under Ambient and Cryogenic Conditions

The worldwide energy transition is accelerating the electrification of industrial and transport networks. In this scenario, induction motors are still widely used due to their robustness and simplicity. Moreover, their usage in high-performance applications with innovative cooling methods is increasing considerably. Cryogenic electric motors have already found their application in several state-of-the-art applications, such as LNG cryogenic pumps, aerospace actuators, and superconducting systems, where the low-temperature operation leads to higher conductivity and lower thermal losses. The thesis investigates the performance of a 15 kW squirrel-cage induction motor under ambient and cryogenic temperatures to evaluate the performance improvement offered by cryogenic cooling. The motor is modeled using the finite element method in COMSOL Multiphysics. Experimental validation is carried out by no-load, locked-rotor, and load tests on the real machine, following IEEE Std 112-1991 standards. Particular care is taken while matching important parameters such as the air-gap and the rotor bridges, taking into account also 3D elements to make the model as accurate as possible. The torque-speed curve is obtained by imposing a set of constant load torques on the machine and simulating the corresponding dynamic balance. The results show that cryogenic operation significantly improves the motor performance in terms of efficiency and torque, demonstrating the potential of cryogenically cooled induction motors for future industrial and energy applications.