Reliability Analysis Of IGBT And Research On Circuit Simulation Model

With the progress of science and technology,the development of power electronics technology is flourishing.It has been widely applied in the field of power system,which to a certain extent also promoted the development and application of power electronics.Insulated gate bipolar transistor(IGBT),as a representative of new power electronic devices,plays a vital role in achieving energy-saving emission reduction and alleviating the long term shortage of energy in China.Therefore,it has been favored by more and more people.However,in the process of encapsulation,the IGBT module will inevitably produce voids in the solder layer.The existence of voids seriously affects the heat dissipation performance of the module,resulting in excessive local temperature of the chip,which reduces the reliability and service life of the IGBT module,and even results in failure of the IGBT.Therefore,it is of great significance to study the influence of voids in the solder layer on the temperature of the IGBT chip,and to improve the reliability and lifespan of the IGBT module.In this paper,we studied the effect of voids in the solder layer on the temperature of the IGBT chips.According to the seven layer structure of the IGBT module,a three-dimensional finite element model was constructed to compare the effect of the voids in the die-bonding layer and the underlay on the chip temperature.The temperature distribution of IGBT modules under different conditions such as the type,size,shape,position,and number of voids in the die-bonding layer and the influence on IGBT reliability are analyzed emphatically,which provides theoretical guidance and suggestion for IGBT module package.The failure of IGBT is an extremely complicated process.In addition to the failure of the IGBT module caused by the high chip temperature,it is also related to the change of the electrical parameters inside the module during the switching process.Therefore,we need to establish an accurate model to study the influence of changes in electrical parameters on its static and dynamic characteristics.In this paper,a semi-analytical model is used to simulate the IGBT internal conductance modulation effect by using a current source to control the voltage source on the basis of the IGBT equivalent circuit,and a static circuit simulation model of the IGBT is established.The parameters of power MOSFETs and PNP transistors are extracted by one-dimensional carrier bipolar transport equations.The sensitivity of the parameters is analyzed using PSpice software,and then the simulation analysis is performed and compared with the data manual provided by the manufacturer to verify the model's effectiveness.Based on the static model of IGBT,the parasitic capacitances between the ports are fully considered,and the nonlinear capacitances inside the IGBT are characterized by the diode's barrier capacitance.The dynamic model of IGBT is established,and the simulation analysis is carried out to verify the model correctness.