【Special Column】Key Technologies of Design, manufacture, operation and maintenance for New Energy Equipment and Their Applications under the Carbon Peaking and Carbon Neutrality Goals
Research on cooling performance of natural air-cooled drive motor with internal oil-cooled chassis
1.Key Laboratory of Advanced Manufacturing Technology for Automobile Parts, Ministry of Education, Chongqing University of Technology, Chongqing 400054, China 2.School of Vehicle Engineering, Chongqing University of Technology, Chongqing 400054, China 3.Chongqing Tsingshan Industrial Co. , Ltd. , Chongqing 402761, China
Aiming at the problems of permanent magnet synchronous motors with high power density, large torque and small volume for vehicle driving, such as small effective heat dissipation area of traditional air-cooled structure and high temperature of internal components caused by electromagnetic loss during operation, an oil-air hybrid cooling method with natural air cooling of internal cavity oil-cooled chassis was proposed, to meet the temperature performance requirements of each component in the drive motor. The equivalent thermal network method was used to calculate the temperature of the stator winding, stator, permanent magnet and rotor in the drive motor under different working conditions, and the highest temperature of the drive motor appeared at the stator winding. Then, the temperature at the stator winding end of the drive motor was measured by experiment and compared with the simulation results. The relative error between the simulation results and the measured results was less than 5%. The results showed that the temperature of the stator winding and other components of the oil-air hybrid cooling drive motor under different working conditions dropped obviously and met the temperature performance requirements, which indicated that the oil-air hybrid cooling method had good heat dissipation performance and high cooling efficiency. The research results can provide reference for the development of heat dissipation systems for vehicle drive motors.
Zehao HUANG,Yanjing XIE,Xiaoting ZHANG,Yongpeng CAO,Dong LI. Research on cooling performance of natural air-cooled drive motor with internal oil-cooled chassis. Chinese Journal of Engineering Design, 2024, 31(6): 733-740.
Fig.1 External characteristic curves of drive motor
运行参数
额定
工况
峰值
工况
高速
工况
超车加速
工况
电流/A
127.5
400
90
292
转速/(r/min)
5 400
4 700
8 500
5 000~7 000
扭矩/(N·m）
26
89
17
65
功率/kW
14
43
14
47
Table 2Operating parameters of drive motor under different working conditions
Fig.2 1/8 two-dimensional model of drive motor
损耗
额定工况
峰值工况
高速工况
超车加速工况
总损耗
906.66
5 193.10
1 387.52
3 880.91
绕组铜耗
350.09
4 322.00
170.17
2 493.60
定子铁损
542.90
822.00
1 197.00
1 319.00
转子铁损
13.46
48.00
19.47
67.23
永磁体涡流损耗
0.21
1.10
0.88
1.08
Table 3Simulation results of drive motor loss under different working conditions
部件及介质
等效导热系数/［W/(m·℃)］
定、转子
30
绕组
387
机壳
150
气隙（空气）
1.05
冷却油
0.14
Table 4Equivalent thermal conductivity of each component and medium of drive motor
Fig.3 Equivalent thermal network node distribution of cooling system for drive motor
部件
对应节点
部件
对应节点
机壳
1~3，33，34
定子齿
17~19
定子轭
4~6
转子
20~25
绕组端部
7，8，15，16
转轴
26~28
轴承
29，30
端盖
31，32
Table 5Corresponding nodes of each component of drive motor
Fig.4 Simulation results of winding temperature with air-cooling under peak working condition
Fig.5 Simplified three-dimensional model of drive motor with oil-air hybrid cooling
水平
因素
甩油孔直径（A）/mm
甩油孔数量（B）/个
进口流量（C）/
(L/min)
1
1.5
2
3
2
2.0
4
4
3
2.5
6
5
Table 6Factor level table for orthogonal design experiment of internal oil-cooling structure
序号
因素水平
温度/℃
A
B
C
1
1
1
1
139.44
2
1
2
3
139.10
3
1
3
2
141.85
4
2
1
3
138.50
5
2
2
2
130.86
6
2
3
1
143.75
7
3
1
2
138.34
8
3
2
1
143.92
9
3
3
3
142.31
Table 7Simulation results of winding temperature under different parameter combinations (rated working condition)
Fig.6 Temperature simulation results of each component of drive motor with oil-air hybrid cooling
工况
最高温度
参考温度
额定工况
130.86
145.00
高速工况
143.52
Table 8Maximum steady-state temperature of winding with oil-air hybrid cooling
工况
最高温度/℃
出现时间/
s
运行20 s的
最高温度/℃
峰值工况
175.90
33.6
145.41
超车加速工况
176.85
22.4
163.43
Table 9Maximum transient temperature of winding with oil-air hybrid cooling
Fig.7 Burial position of PT100 thermistor at the end of winding
Fig.8 Experimental bench for drive motor temperature measurement
Fig.9 Comparison between simulation and measured values of winding end temperature under different working conditions
最高温度/℃
额定工况
峰值工况
高速工况
超车加速工况
相对误差/%
4.8
2.4
4.9
3.5
仿真值
127.98
174.80
141.66
175.67
实测值
122.15
170.63
135.09
169.73
Table 10Comparison of maximum temperature of winding end under different working conditions
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