This paper presents the design optimization procedure of three-phase interior permanent magnet (IPM) synchronous motors with minimum weight, maximum power output for a wide constant-power range. The particular rotor geometry of the IPM motor with several variables and constraints has been implemented by the DoE method. This study is to combine an accurate finite-element analysis with a multiobjective optimization procedure using a new algorithm belonging to the class of controlled random search algorithms. The optimization procedure has been employed to design two IPM motors for EVs. A prototype has been realized and tested. Torque’s current characteristic result comparison between simulated and measured performances shows the reliability of the simulation results of the proposed procedure. The proposal motor design is based on both analytical models and special software to determine the magnetic sizes and geometry parameters of stator and rotor. The experimental test and analytical results have been used to evaluate silicon steel material for designs. To maximize efficiency performance, an optimal algorithm program built-in Matlab and FEM has been written and shown in PC interfaces