Thermal Modeling and Sensitivity Analysis of a Production EV Traction Motor 2019-01-0901
The high performance and reliability of EV electric traction motors is usually constrained by its thermal performance, e.g., demagnetization of permanent magnets and aging of insulation layer of winding wires at elevated temperature. Here we conducted Lumped Parameter Thermal Network (LPTN) simulation of an electrical traction motor used in a production vehicle (GAC’s pure electric GE3 SUV) and also a sensitivity analysis to study various factors which effect motor heat transfer. The LPTN thermal model consists of 74 nodes, in which the copper end turns were each treated as three-layer model to capture the inner temperature gradient. The modeling results were validated by testing results under three critical conditions (40kph @10% grade, 120kph @3% grade, and 140kph @0% grade). The subsequent sensitivity analysis was performed over a range of factors, which include material thermal conductivity, thermal contact resistance at interfaces, loss distribution along copper windings, convective heat transfer coefficient at the two end spaces, and stator-rotor air gap thickness. To study the effect of air gap thickness, theoretic results were computed and compared with CFD results using ANSYS Fluent. The sensitivity study is highly valuable to identify the critical design parameters and further improve the motor thermal management design.
Xiaohui Li, Linpei Zhu, Xiong Liu, Fei Xiong, Jin Shang, Bozhi Yang
GAC R&D Center Silicon Valley Inc., Guangzhou Automotive Eng. Institute