Simulation Of Global Temperature Field For Pure Electric Vehicle Motor Inverter And Calculation Of IGBY Junction Temperature

The good working performance of the electric vehicle motor inverter is an important guarantee for the safe and reliable operation of the whole vehicle.IGBT module,electronic components on circuit board and capacitor are the main power modules of the inverter.It is important to ensure that the junction temperature is always within the allowable temperature range to improve the working performance of the inverter.Taking pure electric passenger car motor inverter as the research object,a method for estimating water-cooled radiator thermal resistance of IGBT was put forward.With the help of a professional thermal analysis software ANSYS Icepak,the thermal simulation analysis and optimization of the whole field temperature field of the inverter were carried out.First of all,calculating the loss of heat-generating devices in the inverter: IGBT module,electronic components on circuit board and capacitor.The way of heat transfer of IGBT module was analyzed,and the equivalent model of thermal resistance was established.Based on the basic theory formula of heat transfer and fluid mechanics,the calculation method of thermal resistance of IGBT water-cooled radiator is obtained,and the junction temperature of IGBT module was directly calculated by the thermal resistance value.This method greatly shortened the R & D cycle of water-cooled radiator and provided guidance on the selection and design of IGBT water-cooled radiator.Secondly,the thermal simulation models of IGBT module,control board,driver board and capacitor were respectively established.The simulation boundary conditions and initial conditions were set according to the actual operating environment of the EV,the fluid-solid coupling simulation of the inverter was performed globally,and the temperature field simulation results of the IGBT module and the capacitor were analyzed.Through the Zoom-in function of ANSYS Icepak,the thermal boundary conditions of the circuit board were extracted.Under the extracted thermal boundary conditions,the control board and the drive board were modeled and simulated in detail.Based on the temperature distribution cloud and the principle of heat design,the layout of electronic components on the circuit board was optimized.Finally,the platform of the inverter temperature test was set up,the temperature of IGBT chip,capacitor and circuit board were monitored by NTC thermistor and infraredthermal imager.The test results were compared with the calculation and simulation results to verify the accuracy of the junction temperature calculation for the IGBT module and the global temperature field simulation.The thermal simulation and thermal analysis of the electric motor inverter were systematically studied through theoretical analysis,numerical simulation and experimental verification,and the design and development cycle was effectively shortened,laying a foundation for the thermal design and optimization of the inverter.