Abstract:

Oil cooled motor has attracted much attention in recent years because of its compact design and good cooling performance. In order to improve the heat dissipation effect of the motor， in this paper the multiphase flow model based on VOF is used to conduct numerical simulation research on two kinds of oil-cooled permanent magnet synchronous motors. Firstly， by comparing the simulation results of the two motors with the experimental results under the rated working conditions， it can be seen that the maximum temperature relative error is less than 5%， which proves that the numerical method is accurate and reliable. Then， the research on the internal oil flow and cooling heat dissipation characteristics of the motor cooling system is carried out under rated working conditions. The results show that the highest temperature of the winding and stator of motor I is 98 and 93.8 ℃ respectively， with the temperature non-uniformity of 4.28% and 5.48% respectively. The highest temperature of the winding and stator of the motor II is 93.0， 92.5 ℃， with the temperature non-uniformity of 3.62% and 5.08%， respectively. At the same time， it is found that although the rotor oil dumping cooling method can make the oil distribution more uniform and improve the cooling efficiency of the cooling oil， it will increase the starting time of the motor cooling system. The study provides theoretical basis for subsequent optimization design of efficient and reliable oil-cooled cooling system.

Key words: electric vehicle, permanent magnet drive motor, numerical calculation, oil cooling method