过流保护机制下IGBT桥臂小尺度短路失效对比分析

Comparative Analysis of Small Scale Short-circuit Failure of IGBT Bridge Leg Under Over-current Protection Mechanism

IGBT小尺度过流短路失效模式、失效机理及失效过程中电参数演变规律等,是提高或改进IGBT应用设计和器件保护措施的重要依据和参考。研究IGBT过流短路失效及其与过流保护装置之间的相互影响和作用机制,对提高IGBT可靠性应用具有重要意义。该文针对造成IGBT破坏性最严重的过流短路失效进行研究,通过对2种不同气密封装结构的NPT型IGBT桥臂进行动态过流短路破坏性实验,揭示桥臂短路电参数的演变规律;在有/无过流保护机制2种情况下,对过流短路的失效模式和失效机理进行微观剖析和阐述。通过各电参数的对比分析,阐明不同能量等级条件下小尺度瞬态短路失效模式与各电气参数具体量化关系,进一步证明IGBT模块在可靠性应用上仍有待进一步的研究和探索。文中所采用的实验方法和所测数据为IGBT可靠性应用提供实验参考和数据积累,同时也为电力电子过流短路故障隔离和器件级容错提供新思路。

The failure mode, failure mechanism and evolution of electrical parameters in IGBT small-scale overcurrent short circuit are important basis and reference for enhancing or improving IGBT application design and device protection measures. The process of studying the failure of IGBT short circuit and its interaction with the overcurrent protection device is of great significance for improving the reliability of IGBT. In this paper, the short-circuit failure which causes the most destructive IGBT was studied. The dynamic short-circuits destructive experiment of NPT IGBT bridge arms with two different hermetic seals was used to reveal the evolution law of short-circuit electrical parameters of bridge arms. In the case of two modes which have the overcurrent protection or not, the failure mode and failure mechanism of short circuit were analyzed and elaborated microscopically. Through the comparative analysis of various electrical parameters, the specific quantitative relationship between the small-scale transient short-circuit failure mode and various electrical parameters under different energy levels was clarified, which further proves that the IGBT module still needs further research and exploration in reliability application. The experimental methods and measured data used in this paper provide experimental reference and data accumulation for IGBT reliability applications, and also provide new ideas for power electronic overcurrent short circuit fault isolation and device level fault tolerance.