Thermal Field Analysis And Heat Dissipation Optimization Of X-ray High Voltage Power Inverter Module

X-ray is widely used in medical diagnosis,industrial nondestructive detection,safety inspection and other fields.As the core device of X-ray generator,X-ray high-voltage power supply is mainly used to provide the accelerated electric field needed for X-ray generation.It is gradually developing towards high frequency,high power density,small size and high reliability.Under this development trend,the heat generation of power supply increases and the volume decreases,which easily causes heat to accumulate in the power supply,thus increasing the device environment temperature,which seriously affects the reliability and service life of the power supply.Therefore,the thermal design of X-ray high voltage power supply is of great significance.In this thesis,finite element software Icepak is used for thermal analysis of inverter with high heat in X-ray high voltage power supply.The work done in this thesis are as follows:According to the characteristics of high power,high frequency and small volume of high-voltage power supply in this project,full-bridge LLC resonant circuit is adopted as the main circuit topology of X-ray high voltage power supply to realize zero-voltage switching on of power switches and reduce the thermal power consumption of the inverters.The parameters of the inverters are designed and circuit simulated is carried out according to the main technical specifications of the high voltage power supply.According to the relevant heat transfer theory,Icepak is used to simulate the temperature of a heat dissipation model.The actual model is analyzed and simplified,and the three-dimensional temperature distribution cloud of the model is obtained which is consistent with the actual measurement results.This proves the rationality of model simplification,mesh generation and boundary condition setting in thermal simulation analysis and the feasibility of using this thermal analysis method to simulate the thermal characteristics of the radiator.According to the working principle of the circuit and the electrical parameters of the components,the power consumption of MOSFET,the main heating components in the inverter module,is calculated.Then the finned radiator which meets the heat dissipation requirement of a single MOSFET is selected preliminarily.Based on that,ANSYS Icepak is used to simulate the heat dissipation performance of finned radiator with single heat source when the base thickness,fin height,fin thickness,fin count and wind velocity change,so as to choose the optimum size parameters and application parameters of the radiator.Then reasonable layout of power devices in inverters is carried out.The effect of heat source spacing on the radiator heat dissipation characteristics is obtained when four heat sources exist at the same time,and a regular hexagonal honeycomb radiator structure is designed to improve its heat dissipation performance.In this thesis,the inverter module of X-ray high-voltage power supply is designed by finite element method,which reduces the node temperature of the main components and improves the reliability of the power supply.It has important practical value.