Temperature Field Simulation Analysis And Heat Dissipation Design Of UAV Power Module

The current flow through the power module,which is used in unmanned aerial vehicle(UAV),may be as high as 200 A,and the heating phenomenon is very serious.It may lead to the destruction of the device and even the safety problem of the aircraft.Therefore,it is necessary to make a study of the heating mechanism and the distribution of the temperature field of the UAV power module,optimize the heat dissipation design,improve the heat dissipation efficiency,and make the UAV power module meet the heat dissipation requirement under the low voltage and large current conditions.Device loss is the main cause of heating.In this paper,the loss calculation of power module is first studied.By establishing a mathematical model,the power module loss is calculated at a junction temperature of 125℃.In order to calculate the loss of power module at any junction temperature,a new calculation method based on spatial interpolation algorithm is proposed,and three ways to improve heat dissipation performance are proposed based on the mathematical analysis of heat transfer process in power modules.Secondly the temperature field distribution of power modules under different structure radiator,different radiator area,different wind speed,different substrate thickness and different thermal conductivity is simulated by the finite element software.Through comparison and analysis,it is found that the biggest influence on the heat dissipation performance is the hindrance of heat conduction caused by solder and thermal conductive silica gel,which points out the right direction for the heat dissipation design of power modules.Thirdly,a new heat dissipation device based on phase change heat dissipation principle is designed,and its design details,structural features and changing forms areelaborated.When the the new designed device is applied to the heat dissipation of the power module,it does not need to smear heat conduction material on the surface of the heating device.The bottleneck of heat conduction is eliminated,and the way of heat dissipation transformed from one-dimensional to three-dimensional.Finally,the heat conduction process of the new designed heat dissipation device on power module is analyzed,The cooling process before and after phase transition is described in detail.The experiment is used to verify the theoretical analysis and simulation results.The heat dissipation performance of traditional power module and new designed power module is compared.In order to get better cooling effect,ethanol and acetone were injected into the new designed heat abstractor respectively,and the influence of different liquids on heat dissipation performance was compared.The results show that the new design of heat dissipation of the power module proposed in this paper can greatly improve the heat dissipation performance.