Research On Physical Modeling And Key Technology Of IGBT Module

Insulated Gate Bipolar Transistor(IGBT),as a power semiconductor device,has many advantages such as high current carrying density and low saturation voltage.It has become one of the core components of power electronic systems and is widely used in electric vehicles,new Energy sources,power grid,rail transit,high voltage transmission and many other key areas.However,with the increase of switching frequency and power density,IGBT modules are increasingly affected by temperature and electronmagmetic interference.Failure of IGBT modules can lead to downtime of power electronic equipment,resulting in economic losses and safety issues.Therefore,it is of great significance to study the reliability of IGBT module for the safe operation of power electronic equipment.The power loss,electrical stress,switching frequency,electromagnetic compatibility,etc.of the IGBT module depend on the dynamic characteristics of the IGBT module,which are important parameters affecting the reliability of the IGBT module.It is essential to accurately simulating the dynamic characteristics of IGBT modules for extracting parameters such as power loss,electromagnetic characteristics and improving the operational reliability of IGBT modules.Therefore,In this thesis,the physical model of IGBT chip and the package circuit model of IGBT module are constructed to accurately simulate the dynamic characteristics of IGBT,so as to provide calculation basis for obtaining power loss and electromagnetic characteristic parameters.The specific research content is as follows:Firstly,the motion mechanism of carriers inside IGBT chip is studied and the theoretical relationship between the dynamic characteristics of IGBT and the motion process of carriers is analyzed,Both of them provides a theoretical basis for constructing the physical model of IGBT chip and calculating the power loss of IGBT module.In addition,the packaging structure of IGBT module is introduced.It is found that the layered structure characteristics of IGBT can cause parasitic parameters between materials and affect the electromagnetic reliability of IGBT operation.This finding provides a theoretical reference for extracting the parasitic parameters of the IGBT module and formulating electromagnetic suppression measures.Secondly,based on the analysis of the one-dimensional and two-dimensional diffusion phenomena of the internal carriers of the chip in the NPT-type IGBT module turn-on state,the physical model of the IGBT chip in the on state is established.A mathematical model is established by the bipolar diffusion equation for the two-dimensional diffusion phenomenon of the MOSFET tail end,and the boundary conditions of the ADE(ambipolar diffusion equation)are given according to the actual experimental conditions.It is calculated and deduced by the backward difference method and solved by MATLAB iteratively,to obtain the approximate behavior of the internal carrier motion of the chip under the IGBT turn-on state,and the accuracy of the theoretical model calculation result is verified by experimental tests.The model accurately simulates the dynamic behavior of the IGBT chip turn-on and turn-off process,can accurately calculate its power loss,obtain the junction temperature of the IGBT chip,and improve the thermal reliability of the IGBT module operation.Finally,this thesis studies the geometry and material properties of the internal structure of the IGBT module.With the help of parasitic parameter measuring equipment such as precision impedance analyzer,a direct extraction method of parasitic parameters of IGBT module package circuit based on series-parallel resonance theory and two-port network theory is proposed,and establish The IGBT module package circuit model.The measurement results and finite element simulation results are compared to verify the feasibility and accuracy of the model.