Reliability tests on power devices

Abstract

System dependability has become an important aspect to consider because of the large number of components included in modern systems and the high availability requirements that users demand. In systems such as switch-mode power supplies, power devices like IGBTs play a fundamental role in system functionality and performance, hence the use of reliable components is key. In this paper, the design of dependable systems based on reliable power devices is addressed. Reliability tests have been carried out on a set of IGBTs used in a battery charger to extract accurate reliability prediction models for this type of devices and degradation models, which can help the system designer to generate highly dependable systems. This paper describes the first phase of the authors' research that focus on determining degradation models for IGBTs due to environmental causes. Their tests show the high resistance of the selected devices to environmental stress. None of the devices has failed the tests, and the variation in their electrical characteristics is minimal. This is an important conclusion because our final objective is the design of reliable battery chargers, which requires the use of power devices that can tolerate high stress without degradation of their characteristics. In addition, they were able to detect a flaw in their measurement methodology that helped them to improve their test and analysis flow for the second phase of their research.