Computation of eddy currents in a solid rotor induction machine with 2-D and 3-D FEM

Abstract

Although a two-dimensional numerical analysis of an electrical machine provides an approximately accurate solution of the electromagnetic field in the machine, a three-dimensional study is needed to understand the actual phenomena. But due to the large problem size and the complex geometries, the three dimensional model requires a huge amount of degrees of freedoms (DoFs) to be solved, which is not possible with a limited computing resources. Therefore, a coupled 2D-3D model can be the best alternative to solve such type of problems. In this thesis, a 2-D finite element analysis is performed on a solid rotor induction motor by an in-house software FCSMEK. The eddy current in the solid steel rotor was computed. A 3-D model for the same machine was built and solved in COMSOL MultiphysicsTM. To reduce the computation time of the 3-D model, the solution of the 2-D model was used as the source to the 3-D model where the stator current density is used as a transferred variable. The eddy currents are computed and the results from both 2-D and 3-D simulations are compared. Other quantities of interest such as the torque of the machine computed with the 2-D and 3-D models are also computed and compared.