基于高速动车组服役环境下的功率器件主端子连接结构设计与评价

Design and evaluation of main terminal connectors for power modulesin the service environment of high-speed EMUs

为了提高高速动车组服役环境下功率器件主端子连接结构的服役可靠性,文章通过有限元分析对IGBT器件主端子结构焊层的疲劳可靠性进行研究,并且运用不同的理论预测焊层疲劳寿命并通过功率循环试验进行了验证。结果表明,随着主端子焊层孔洞率的增加,循环周次会降低,但影响并不明显。随着主端子焊层厚度逐渐增加,循环周次呈现出先增加后减少的变化规律。在功率循环过程中,主端子结构焊层的退化表现为灰色含Sn相的粗化,采用基于能量的Darveaux模型进行分析更加符合功率器件主端子结构焊层的退化过程。故在主端子结构中,影响其服役寿命的主要因素为焊层厚度。

This paper aims to improve the service reliability of main terminal connectors for power modules in the service environment of high-speed EMUs.To achieve this,the fatigue reliability of the solder layers in the main terminal structure of insulated-gate bipolar transistors(IGBTs)was studied through finite element analysis.In addition,the fatigue life of the solder layers was predicted by leveraging different theories and the prediction results were verified by power cycle experiments.The study results show that the number of cycles decreases slightly with the increase in the void rate of the solder layers.Additionally,as the solder layer thickness increases,the number of cycles initially increases before subsequently decreasing.During the power cycle experiments,the degradation of the solder layers manifests as the coarsening of the grey phase containing Sn.The analysis obtained using the energy-based Darveaux model more closely aligns with the degradation process of the solder layers in the main terminal structure of IGBTs.Hence,the thickness of solder layers is identified as the primary influencing factor on the service life of the main terminal structure.