Development of constrained optimization routine for the U.S. DRIVE specifications using coupled electromagnetic/thermal electric machine model

The task of applying numerical design optimization techniques to traction motors increases in complexity when there are complicated combinations of demanding performance specifications and physical dimension constraints that must be satisfied. This paper presents a constrained optimization routine that can be used to efficiently optimize electric machine designs to meet demanding U.S. DRIVE traction motor specifications. This approach uses a previously-developed coupled electromagnetic (EM)/thermal model that is capable of quickly determining the maximum current density during the machine´s transient operation. The proposed optimization routine is applied to three 10-pole, 12-slot surface PM machine designs that were optimized for maximum torque density, minimum cost, and maximum efficiency, respectively, without changing their lamination cross-section dimensions. The results confirm the promising features of this approach for handling challenging machine design problems that include complicated combinations of performance specifications and constraints.