Pre-Compressed Multistrand Bar Conductors for High-Power Density Traction Applications

Flat conductors are gradually replacing random winding due to their higher slot fill factor, lower dc resistance, and better thermal performance. However, high-frequency loss and relatively expensive manufacturing costs are the prominent problems of flat conductors, in which to some extent restricts their application in high-power density and high-speed motors. Therefore, this article conducts a study on the application of pre-compressed multistrand bar conductors (PCMSBCs) in motor design required high-power density for electric traction drive systems. First, the influence of the modular stator used in conjunction with multistrand bar conductors on the performance of the prototype is qualitatively analyzed. Second, by precisely modeling the placement of each conductor, the ac copper losses in the preformed winding structure and its components are analyzed. In addition, based on the loss characteristics of multilayered bar windings, each row is accurately modeled to predict the temperature distribution of an existing prototype. Finally, experimental contents allow verifying the correctness of the loss calculation, thermal analyses, and prototype performance under continuous operations up to 20.3 A/mm2.