基于任务剖面的牵引变流器IGBT模块焊料层疲劳应力与剩余使用寿命的映射方法

A Mapping Method of Solder Layer Fatigue Stress and Remaining Useful Life for IGBT Module in a Traction Converter Based on the Mission-profile

牵引变流器中绝缘栅双极型晶体管(insulatedgate bipolar transistor,IGBT)模块的可靠性与列车的安全可靠运行息息相关。针对列车在运行过程中具有牵引、制动、惰行等多任务剖面,使得IGBT模块焊料层承受着变化的热应力而发生老化,进而影响IGBT模块的可靠性的问题,提出一种基于任务剖面的焊料层应力与剩余使用寿命映射的模型。首先,分析牵引变流器的功率损耗,依据牵引特性曲线并结合双机对拖模型建立IGBT和续流二极管的功率损耗数据空间,进而分析不同牵引特性区间的损耗–转矩–转速规律。然后,建立IGBT模块的有限元模型,以限速为80km/h任务剖面的平均损耗为输入条件,分析全新、25%、50%等3种不同老化程度焊料层的温度场和热应力场,讨论直接覆铜板(directbondedcopper,DBC)焊料层和芯片焊料层的热应力与温度、老化程度的关系。最后,引入优化后的疲劳寿命模型,通过求解不同老化程度下DBC焊料层所受热应力对应的弹性应变,拟合得到DBC焊料层热应力和剩余使用寿命的映射关系模型,得到的寿命趋势与分析相吻合。研究内容可为牵引变流器中IGBT模块焊料层的寿命评价提供一定指导意义。

The reliability of IGBT module in traction converter is closely related to the safe and reliable operation of train.The IGBT module solder layer is aged under the changing thermal stress due to the multi-profile of traction,braking and coasting during train operation,which affects the reliability of IGBT module.In order to solve the problem,this paper proposed a mission-profile-based mapping model of solder layer fatigue stress and remaining useful life(RUL)of IGBT Module.Firstly,the power loss of the traction converter was analyzed,and the power loss data space of IGBT and Diodes was established according to the traction characteristic curve and combined with the motors back-to-back model and then the loss-torque-speed law in different traction characteristics was analyzed.Then,the finite element model of IGBT module was established.Taking the average loss of mission-profile with speed limit of 80km/h as the input condition,the temperature field and thermal stress field of solder layers with different aging degrees of brand-new,25%and 50%were analyzed,and the relationship between thermal stress and temperature and aging degree of direct bonded copper(DBC)solder layer and chip solder layer was discussed.Finally,the optimized life model was introduced.By solving the elastic strain corresponding to the thermal stress of DBC solder layer under different aging degrees,the mapping model between thermal stress and RUL of DBC solder layer was obtained by fitting.The obtained life trend is consistent with the analysis.The research content of this paper can provide guiding significance for the life evaluation of solder layer of IGBT module in traction converter.