Fluid Dynamic Modeling of Composite Oil-Cooled Motors with Flat-Wire Concentrated Windings

In the context of high-power density applications, oil-cooled motors have emerged as a research focus due to their superior cooling performance. The optimized design of cooling structures and the development of fluid analysis methods are crucial for improving overall system performance. In this study, a composite oil-cooled structure with concentrated flat-wire windings is proposed to enhance heat dissipation capability. Based on this configuration, an innovative hydrodynamic modeling approach for the stator and rotor oil channels is developed, effectively addressing the low efficiency of conventional finite element simulations. Using the proposed modeling method, the internal flow non-uniformity of the oil-cooled motor is analyzed, revealing the mechanisms by which key structural parameters affect heat transfer non-uniformity. Finally, experimental results demonstrate that the proposed model provides accurate flow rate predictions. The prototype achieves a continuous current density of 33.6 A/mm², with a peak motor temperature of 130 °C—representing a 60.7% improvement compared to conventional oil-cooling solutions.