Efficient finite element based rotor loss calculation for permanent magnet synchronous machines

This paper proposes a finite element based method to compute rotor eddy-current losses in surface mounted PM machines. A surface current density boundary condition, obtained from static solutions of the full machine geometry, is applied to a model containing only the rotor. Unlike other similar methods, this method is not based on the assumption of resistively limited eddy-currents; it can account for shielding effects in the rotor. The performance under various conditions is demonstrated with a number of hypothetical machines, showing the proposed method underestimates the rotor losses by up to 16%, but also reduces the computation time required by a factor 2-20, compared to transient simulations with the full geometry.