This paper develops a novel method for optimal design of fractional slot with concentrated windings. The basis of this method is a generalized analytical model of the winding magnetomotive force (MMF) combined with a multiobjective genetic algorithm, which searches the optimal winding parameters that maximize the winding factor and minimize the MMF harmonic content. This technique is applied to optimize the winding layout of the permanent magnet synchronous machine with 12 x n slots/10 x n poles combination (n is an integer number). The electromagnetic performances of the optimized winding are investigated and compared with conventional winding topology. It is found that the proposed approach allows the emergence of new windings with higher performances.