Coupled FEM-Control Simulation in the Analysis of Electrical Machines and Converters

Coupled simulation environment is presented, where electrical machines are modeled by the finite element method (FEM) with circuit equations and coupled to converter models in a system simulator. The method is based on weak coupling, providing possibility for multiple time step levels in the system model. Examples concerning the analysis of current and voltage harmonics, additional losses and tooth forces, are presented for 2 MW cage induction motor, 9 MW and 12.5 MW synchronous motors and 1.5 MW permanent magnet synchronous motor supplied by frequency converters. Also the future outlook of coupled FEM-system simulation is discussed in terms of the actual need for coupled models and the research interests on the coupling method development.