FEA-based multi-objective optimization of IPM motor design including rotor losses

The design optimization of IPM motors for wide speed ranges is considered in this paper by means of a FEA-based multi-objective genetic algorithm (MOGA). The minimum number of simulations is pursued for the fast evaluation of four goal functions: maximum torque, minimum torque ripple, maximum flux weakening capability and minimum rotor harmonic losses. The paper is focused on the rotor design, that is the most controversial aspect of IPM design due to the difficult modeling dominated by magnetic saturation. Three original results are presented: the elimination of higher order torque ripple harmonics and the minimization of FEA evaluations by means of a random rotor position offset and the evaluation, by means of the same static FEA runs, of the eddy current losses in the rotor core.