以48 V扁线绕组感应电机为研究对象，采用COMSOL软件温度场仿真计算方法，研究感应电机的转子旋转搅动冷却油的被动冷却方式对感应电机温度场分布的影响和热均衡效果。将三维电磁场分析的难度降维为电机轴向中部平面进行二维电磁场分析，以简化计算并得到其磁通密度分布图，由此计算出电机各部分的损耗值。建立该电机简化的三维全域仿真模型，并对其进行了大电流工况下瞬态热分析，仿真结果表明：被动油冷电机中气隙、转子、绕组的温升得到了明显减少。在两台相同性能参数的电机上进行空气冷却和被动油冷方式冷却温升试验，试验结果表明：与风冷系统相比,被动油冷系统能显著改善电机的转子、扁线绕组的温升，电机输出功率得到明显提升，是一种较为经济且可靠的散热系统。

The 48 V flat wire winding induction motor is taken as the research object, the influence of oil-passive cooling of the rotor of induction motor on the distribution of temperature field and the thermal equalization effect is studied by using COMSOL software. Three-dimensional electromagnetic field analysis is transformed into two-dimensional analysis on the axial middle plane of the motor to simplify calculation and obtain flux density distribution, the loss value of each part of the motor is calculated. A simplified three-dimensional global simulation model of the motor is established, and the transient thermal analysis of the motor is carried out under the large current condition. The simulation results show that the temperature rising of the air gap, rotor, winding in the passive oil-cooling motor is obviously reduced. Through the temperature rising experiment of air cooling and the passive oil-cooling in the two motors with the same parameters. The experiment results show that, compared with air cooling system, passive oil-cooling system can significantly improve the effect of temperature rising of the rotor and winding in the motor, and raise the output power of the motor, which is an economic and reliable cooling system.