1D-3D Coupled Analysis for Motor Thermal Management in an Electric Vehicle

Motor thermal management of electric vehicles (EVs) is becoming more significant due to its close relations to vehicle aerodynamic performance and power consumption, while computer aided engineering (CAE) plays an important role in its development. A 1D-3D coupled model is established to characterize transient thermal performance of the motor in an electric vehicle on a high performance computer (HPC) platform. The 1D motor thermal management model is integrated with the 1D powertrain model, and a 3D thermal model is established for the motor, while online data exchange is realized between the 1D and 3D models. The 1D model gives boundaries such as inlet coolant temperature, mass flowrate and motor heat generation to the 3D model, while the 3D model gives back boundaries such as heat transfer to coolant simultaneously. Transient simulations are performed for the 140kph(20°C) driving cycle, and the model is calibrated with experimental data. The calibrated model is then applied to the WLTC (15°C) cycle without further parameter modification, and the simulation results are compared with experiments. The comparison shows that the model can predict the system’s performance with satisfactory accuracy for engineering applications. Sensitivity analysis is performed for control parameters including cooling fan level and electric pump speed to investigate potential optimization opportunities. Effects of these two parameters on motor coolant and stator temperatures are shown and discussed. This work proves the 1D-3D online coupling method to be useful tool in motor thermal management design, especially at early stages of development.