STUDIES ON IGBT MODULE TO IMPROVE THE RELIABILITY OF POWER ELECTRONIC SYSTEMS

摘要

As power electronic systems have gradually gained an important status in a wide range of industrial applications, there are increasing demands to improve the reliability and robustness of power electronic systems. The power electronic systems consist of various components, and among them, power semiconductor devices are one of the most fragile components. Thus, they play a key role in the robustness and reliability of the overall power electronic systems. Insulated Gate Bipolar Transistor (IGBT) power modules are the most widely used of their kind and the temperature stress is a major stressor that kills IGBT modules. Therefore, in order to improve the reliability of power electronic systems, reliability research on reliability-critical components regarding the major critical stressors are needed. In this PhD project, various researches on reliability of the IGBT module are performed from component level to converter level.It is divided into two main parts: the first part, which consists of Chapters 2 and 3, is reliability studies of the IGBT module regarding thermal stresses and the second part, composed of Chapters 4 and 5, discusses strategies to improve the reliability and availability of power electronic converters under IGBT failure conditions. The apparatus and methodology for an advanced accelerated power cycling test of IGBT modules are presented in Chapter 2. Further, an improved junction temperature estimation method is also proposed as well as power cycling test results are presented. Then, in Chapter 3, the effect of junction temperature swing duration t△Tj on the lifetime of the transfer molded Intelligent Power IGBT Module is investigated and modeled based on the power cycling test results. In addition, the physics-of-failure analysis results of the tested modules are presented. Finally, in Chapters 4 and 5, open-circuit fault detection and fault-tolerant control methods are proposed for two kinds of neutral-point clamped three-level inverters T-type and NPC inverters.One of main contributions in this project is the development of an apparatus and methodology for advanced accelerated power cycling test of IGBT modules. It allows performing the reliability test regarding temperature stresses under more realistic electrical conditions in an efficient way. Therefore, a more practical reliability assessment of power IGBT modules can be achieved with respect to lifetime as well as failure mechanisms. Furthermore, it introduces new control strategies to improve the reliability and availability of two types of the neutral-point clamped three-level converters under open-circuit fault conditions.The feasibility and effectiveness of this project are verified by various experimental results.