计及焊层疲劳影响的风电变流器IGBT模块热分析及改进热网络模型

针对不同疲劳寿命时期对风电变流器绝缘栅双极型晶闸管(IGBT)模块结温的影响,分析焊层在不同脱落度下的IGBT模块热阻变化规律,并建立考虑热阻变化的改进热网络模型。首先,依据风电机组变流器IGBT模块的结构和材料属性,建立三维有限元热-结构耦合分析模型,对基板焊层和芯片焊层在不同脱落度下IGBT模块结温和热应力的分布规律进行仿真分析。其次,确定不同焊层脱落度下其热阻增量值,并建立IGBT模块改进热网络模型。最后,将三维有限元模型和改进热网络模型的结温计算结果进行对比分析,验证了所提的改进热网络模型的有效性。

Thermal Analysis and Improved Thermal Network Model of IGBT Module for Wind Power Converter Considering Solder Fatigue Effects

Due to the influences of different fatigue lifetime stages on the junction temperature of the insulated gate bipolar transistor (IGBT) module in wind power converter, this paper analyzes the thermal resistance characteristics in different solder desquamating degrees, and then presents an improved thermal network model of the IGBT module. First, based on the structures and material parameters of the IGBT module of wind power converters, the coupling thermal-structure 3D finite element fatigue model of IGBT module is established. The junction temperature and thermal stress of IGBT module are investigated in different desquamating degrees of base plate solder and chip solder. Second, the thermal resistance parameters are determined in different desquamating degrees, and the improved thermal network model considering solder fatigue effects is established. Finally, the results of junction temperature calculated by the improved thermal network model are compared with those by the 3D finite element fatigue model, which testify the effectiveness of the improved thermal network model.