Temperature rise study of a permanent magnet synchronous motor with novel split-transposition windings

In the permanent magnet synchronous motor (PMSM) with the flat wire winding, the skin and proximity effects cause a significant increase in AC losses, leading to excessive temperature rise. To address this issue, this paper investigates the thermal characteristics of the novel split-transposition winding structure in a 60 kW PMSM, comparing it with the conventional flat wire winding structure. The analysis is performed using a coupled magnetic-thermal-fluid multiphysics method. Initially, a coupled magnetic-thermal-fluid model for the motor with the novel winding is established. Based on the coupled magnetic-thermal-fluid method, the thermal characteristics of motors with conventional flat wire winding and the novel split-transposition winding were simulated under rated operating conditions, from which the respective heat source distributions, water flow characteristics, and component temperature distribution patterns were obtained for comparative analysis. The accuracy of the coupled model is then validated through experimental temperature rise test. The results demonstrate that the novel split-transposition structure effectively reduces the maximum winding temperature during operation and mitigates the axial temperature variation among the strands, thus alleviating the severe temperature rise problem inherent in the conventional flat wire winding.