大功率IGBT状态监测与可靠性在线评估

As the large capacity power electronics equipments become widely used, the demands to the reliability of power electronics devices turn to be more stringent. However, the existing fault detection and protection methods cannot predict the occurrence of failures, thus may lead to irreparably heavy losses. This project is the extension and topology research of the completed national science foundation key project, the research on basic theories and critical techniques of large capacity and special power electronics systems (50737004). Research on condition monitoring and on-line reliability evaluation is carried out based on the investigation of high power IGBT modules. The external port parameters and their degradation characteristics corresponding to each failure mode will be ascertained through the in-depth research on the internal failure mechanisms and failure modes. Next, the accurate detection of those parameters can be achieved by means of advanced detection methods, and the real time monitoring and on-line evaluation of IGBT's operation status and reliability can also be realized in the power electronics equipments. Therefore, the IGBT failures can be precisly predicted in the pre-failure stage, avoiding severe accidents and losses caused by the degradation of IGBT reliability and failures. The research achievments will have great significance to the reliability improvement of power electronics devices and the whole equipments, and can also be migrated to other types of power electronics devices and be extended to the power electronics equipments in both military and civil applications.

大容量电力电子装置的广泛应用对电力电子器件的可靠性提出了越来越高的要求，然而现有的故障检测与保护方法无法预防器件本身的失效发生，有可能造成不可弥补的重大损失。本项目是已完成的自然科学基金重点项目《大容量特种高性能电力电子系统基础理论与关键技术》（50737004）的延伸和拓展研究，将以大功率IGBT模块为主要对象开展状态监测与可靠性在线评估研究。深入研究IGBT内部失效机理与失效模式，分析得到与各种失效相对应的外部特征量及其变异特性，通过引入先进的检测方法实现特征量的准确检测，在电力电子装置中对IGBT运行状态与可靠性进行实时监测和在线评估，从而在IGBT的预失效阶段实现对失效的准确预测，避免由IGBT可靠性下降与失效引起的严重事故和重大损失的发生。研究成果对于提高电力电子器件与整个装置的可靠性具有重要意义，也可移植应用于其它电力电子器件，并推广到军用和民用的各种电力电子装置中。

IGBT器件已广泛应用于各种中、大功率电力电子装置，是目前应用最为广泛的全控型电力电子器件。作为电力电子装置的核心组成部件，IGBT器件的可靠性已成为决定整个装置安全运行的最重要因素。而诱发IGBT失效的主要失效模式为封装疲劳失效，因此，本项目针对IGBT封装疲劳失效机理及其状态监测与可靠性评估方法开展研究。基于IGBT基本结构、半导体物理理论和器件可靠性物理学，查明了与封装相关的疲劳失效机理，并确定铝金属薄膜、键丝、焊料层疲劳失效是其主要失效模式；查明了焊料层空洞大小、位置、分布对IGBT结温和温度分布的影响及其变化规律；建立了饱和压降与热阻随疲劳老化应力水平与施加时间的变化规律及其状态监测与可靠性评估方法；建立了基于电压变化率的结温预测模型，并进行了实验验证。本项目研究成果可应用于IGBT器件及其电力电子电能变换装置，以提高其可靠性。