Engineering practical thermal evaluation method of wrap-around liquid-cooled motor

To meet the increasingly rigorous operational demands in motor applications, enhancing the torque output capacity has become a crucial area of focus for advancing industry growth. Given the limitations imposed by thermal constraints on a motor's torque output, this paper presents a wrap-around liquid-cooled thermal management system as an efficient solution, using a 40 kW permanent magnet synchronous motor (PMSM) as a case study. Additionally, to enable fast and accurate temperature distribution analysis of each motor component during the design phase, a magneto-thermal coupling model is developed based on a three-dimensional thermal network. This model incorporates both electromagnetic loss, node temperature, and thermal parameters while also accounting for the temperature-dependent characteristics of materials and thermal properties. The finite element analysis method and mock-up experiments verify the accuracy of the thermal evaluation model and cooling efficiency of the wrap-around liquid-cooled motor. The proposal of the wrap-around liquid-cooled scheme further improves the thermal management efficiency of the motor, with a 44.5% increase compared to the indirect casing cooling scheme. The establishment of a coupled model not only improves the accuracy of analysis, but also significantly reduces the cycle of thermal evaluation, which has important guiding significance for the design and optimization of motors in engineering practice.