Electromagnetical model of an induction motor in COMSOL Multiphysics

Abstract: Ansys, Flux or COMSOL are examples of software-tools that can be used to study magnetic noise, caused by magnetic forces in the air-gap, in induction motors. The project team wanted to use COMSOL in this thesis. The electromagnetical domain needs to be coupled to the mechanical domain to complete the study. The air-gap forces, calculated in the electromagnetical model using the Rotating Machinery module, can be exported to the Acoustic-Solid Interaction module in COMSOL to enable the vibro-acoustic analysis. An electromagnetical model of an induction motor is developed in two-dimensions in the finite element method based software-tool COMSOL Multiphysics in this thesis. Simulation results obtained in the frequency domain are compared with results achieved in the software-tool FEMM. Simulation results of the phase inductance, distribution of the flux density and the torque are compared. The simulated torque in COMSOL is validated with the torque derived based on an equivalent lumped model of the induction motor. A time-dependent simulation of the motor is made at 4.7% slip and 1A (peak) supply. The obtained torque is 0.33Nm. The same value is achieved in the frequency study in COMSOL. The corresponding value is 0.003Nm higher in FEMM. The evaluated air-gap forces at 4.7% slip can be used for studying vibro-acoustics in COMSOL.