Multiobjective optimal design of interior permanent magnet synchronous motors considering improved core loss formula

This paper describes the optimal design of interior permanent magnet synchronous motors for which two objective functions regarding motor efficiency and weight are used. Multiobjective optimization technique is applied to finding the optimal solution in this case. An optimal design method that determines both the noninferior solution set and the best compromise solution employing a modified genetic algorithm is proposed. The proposed algorithm adopts the structure of the conventional genetic algorithm, but fitness value and convergence criterion are redefined and some major parameters of the algorithm are adjusted to the multiobjective optimization. In order to predict the motor performance more accurately, a core loss formula is derived considering the flux variation due to the stator currents as well as that due to the magnet.