Structure Design Along With Pressure And Temperature Calculation Of Press-Pack IGBT Device

In recent years,the new energy industry has developed rapidly in China.As the core power electronic devices in circuit breakers and converter valves,IGBT devices are widely used in high voltage and high power applications such as flexible DC transmission.It is of great significance to improve the reliability of IGBT devices for safe and reliable operation of the power grid.The temperature and the pressure are two major factors that affect the reliability of IGBT devices and the consistency of parallel chips.In order to improve the heat dissipation performance and pressure sharing performance of IGBT devices and ensure the consistency of the working characteristics of the parallel submodules in the devices,the optimal design and performance evaluation of the press-pack IGBT device are carried out in this paper.At the same time,in order to break through the limitation of finite element method and obtain the temperature and pressure of IGBT devices more quickly and effectively,the rapid acquisition method of IGBT device temperature and pressure was studied in this paperIn order to analyze the performance of the new IGBT structure proposed in this paper,the finite element models of three different IGBT modules were constructed.According to the actual working condition of IGBT devices,the reasonable boundary condition settings were discussed,and the temperature and pressure of three IGBT modules were calculated.By changing the shape and material of the new structure proposed in this paper,the structure was optimized to achieve the optimal performance.Based on the finite element calculation results of temperature and pressure,the heat dissipation performance and equilibrium pressure performance of three IGBT structures can be analyzed and evaluated.When the consistency of parallel branches of IGBT modules is improved,the feasibility of the IGBT module one-dimensional simplification is also improved.The finite element method was used to verify the assumptions of the IGBT module one-dimensional simplification.One-dimensional models of the three IGBT module single branch were established,and a one-dimensional coupling calculation method of temperature and pressure was proposed.Based on heat transfer equations,frequency domain analysis,thermal network method and mechanical equations,the theoretical basis of the proposed method was discussed.Unidirectional coupling of temperature field and pressure field can be realized by using thermal expansion caused by temperature change to calculate the pressure.By introducing the contact thermal resistance and contact resistance changed with the pressure as well as the chip heat loss affected by the pressure and the temperature,a bidirectional coupling calculation model of temperature and pressure can be established.Considering the influence of the actual IGBT module's heat dissipation condition,the heat flow diffusion and the pressure edge effect,the one-dimensional model modification methods including the direct calculation method and the transient thermal impedance method were introduced in this paper.The performance of heat dissipation and pressure equalization of IGBT devices were analyzed by the finite element method.It is shown that the proposed structure can achieve both double-sided heat dissipation and balanced pressure.The finite element method was used to verify the one-dimensional temperature and pressure calculation method under different conditions.The calculation results of the one-dimensional temperature and pressure calculation method proposed in this paper is very similar to that of the finite element method for three different IGBT module structures.Simplifying the IGBT module to a one-dimensional model for temperature and pressure calculation has certain applicability.