Thermal Simulation And Thermal Analysis Of Water-cooled Electric Machine’s Controller For Electric Vehicle

IGBT is the key module of water-cooled electric machine’s controller for electric vehicle. The controller can’t reach the design capacity, and can’t work long hours in rated working condition and can’t work in short time in peak working condition because the heat dissipation of IGBT is bad. Then the accidents seriously affect the stability of the vehicle. So it is urgent to solve the problem of the heat dissipation of electric machine’s controller. This paper was based on the research project of water-cooled electric drive system for electric vehicle. Taken the IGBT module of electric machine’s controller for electric vehicle as the main research object, the IGBT module was thermal simulated, thermal analyzed and experiment validated by the professional thermal analysis software ICEPAK.First, the related theoretical bases of thermal analysis were elaborated, including heat transfer theory, fluid mechanics, fluid dynamics theory, cooling methods, thermal resistance and pressure drop. These theories laid the foundation of solving the three-dimensional steady state flow fields and heat conduction problems and predicting the evolution of the temperature fields and flow fields.Then, combined with the theories above-mentioned, three heatsinks’models were established, and they were thermal simulated and thermal analyzed by thermal analysis software ICEPAK to compare the cooling effects of three kinds of heatsinks under the same boundary conditions. By comparing the temperatures of the IGBT modules, heatsinks’thermal resistances and pressure drops, the results reveal the cooling effect of fork row needle column heatsink is best, finned heatsink is second, s-shaped passage heatsink is poorer.Taken fork row needle column heatsink as the optimization object, the thermal needle arrangement was optimized at first. When the number of needles is662, the heatsink is best because that the thermal resistance is small and the pressure drop is not high. Then the velocity of water entry was optimized. When the velocity is6L/min, the thermal resistance is small and the pressure drop is low, the goal of the optimization has been achieved.To test the accuracy and feasibility of the numerical simulation of the IGBT module through ICEPAK software, the engineering experiment was designed. In the premise of guaranteeing the accuracy as much as possible, the corresponding experimental data were obtained. Finally the simulation results and the experimental results were compared, and the causes of the error were analyzed.In this paper, structure design, simulation analysis and experimental verification were combined, and then formed a complete set of system of thermal simulation and thermal analysis of IGBT module of electric machine’s controller of pure electric vehicle, and laid a certain foundation for the further optimization of the controller’s cooling system.