Enhanced Cooling Strategy of YASA Axial Flux Permanent Magnet Motor for Electric Automobile Application

Addressing the thermal management challenges associated with the stator and rotor system of Yokeless And Segmented Armature (YASA) motors, this paper proposes an enhanced cooling strategy for the stator and rotor. Taking a dual-rotor single-stator YASA motor as the research subject, the volume of fluid (VOF) model is employed to evaluate the cooling performance of existing advanced oil cooling technique. Subsequently, The stator bracket is perforated to enable cooling oil to flow into the air gap area for direct heat exchange with the stator and rotor system. By investigating the impact of the number of holes on both the motor’s cooling performance and oil friction loss, the optimal hole configuration is determined to be a direct cooling solution with hole of 1*1.5mm. Compared with the existing cooling scheme, the maximum temperatures of windings, stators, permanent magnets and rotors under rated conditions are reduced by 29.14%, 28.53%, 51.67% and 50.21%, respectively. Through the comparison of temperature rise experiments, the accuracy of thermal simulation modeling and the efficiency of the cooling system are further verified, which provides a new method for the design of efficient cooling system of YASA motor.