Aspects of electromagnetic-thermal coupled optimization of asynchronous machines for traction drives

The growth of power density in traction motors requires disproportionally more heat to be discharged which leads to the need for more and more advanced cooling techniques. In this paper a novel evaluation and optimization approach for internal air cooled traction machines will be presented. It investigates the electromagnetic performance combined with the aero- and thermodynamic cooling performance. In a first step analytical/ empirical models are used to speed up the calculation time for obtaining pressure drop, volume flow distribution and heat transfer as well as iron stack temperature. The results are validated using computational fluid dynamics simulations of several iron stack cooling duct geometries. Finally, a setup is presented about how the optimization can be implemented coupling electromagnetic losses obtained by finite element analysis with the analytic thermal model.