Multiphysics-Based Numerical Prediction of the Electromagnetic and Thermal Performance of a 160 kW SSDR Axial-Flux Motor

Abstract

Abstract

Axial-flux motor (AFM) can achieve high torque and power density; however, integrated electromagnetic and thermal design is required to manage losses and heat generation during high-power operation. In this study, an AFM with a target output power of 160 kW for electric vehicles was analyzed using three-dimensional electromagnetic and thermal-fluid analyses. Electromagnetic analysis evaluated back EMF, cogging torque, torque, output power, efficiency, and losses. Current phase-angle control was applied at high speeds considering the 700 V line-to-line voltage limit of the 800 V inverter. At 300 A and 4500 rpm, the motor achieved an output power of 150 kW with an efficiency of approximately 94%. Electromagnetic losses were applied as heat sources in the thermal analysis. In the Base model, nonuniform oil flow caused local high-temperature regions. The model incorporating eight ribs in the oil-flow path and 12 rotor blades for enhanced air cooling reduced the maximum coil temperature from 194 °C to 170 °C and the maximum stator temperature from 205 °C to 113 °C. The model reduced the standard deviations of coil and stator temperatures by 50.6% and 58.6%, respectively. The proposed multi-physics method predicts electromagnetic and thermal characteristics and supports operating control and cooling system design.