Real-time Failure Monitoring System for High Power IGBT Under Acceleration Test Up to 500 A Stress

Real-time failure monitoring system for IGBT module was demonstrated under 500 A power cycling test. The system successfully captured internal phenomena occurred in interface regions of the device under test. Moreover, we proposed realtime failure analysis method by combining the real-time monitoring and image processing techniques. This failure analysis method enables to distinguish the place where degradation occurs in DUT and also trace internal degradation process to failure.2014 IEEE 26th International Symposium on Power Semiconductor Devices & IC\u27s (ISPSD), Jun 15-19, 2014, Hilton Waikoloa Village, Hawaii, US

Real time degradation monitoring system for high power IGBT module under power cycling test

A “real time” monitoring system which enables to observe internal degradation process to failure of power semiconductors under power cycling test is proposed. The system was realized by combining a scanning acoustic tomography (SAT/SAM), power stress controlling, device cooling, water jet system and chip temperature monitoring. Two contradictory problems, namely, electrically wiring for power cycling and waterproof of device for SAT imaging were compatible with each other by experimental setup with an original water tank. Self-heating of power devices was supressed by controlling temperature of water which is couplant of ultrasonic wave for the SAT. A demonstration of this system was performed by using an IGBT module which maximum rating of collector current was 400 A (DC).24th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis. Schedule, September 30-October 4, 2013, Venue, Arcachon, Franc

Failure Analysis of Power Devices Based on Real-Time Monitoring

The aim is to provide failure analysis of power devices based on real-time monitoring. The real-time monitoring provides a time-domain data related to a failure mechanism. The data includes important information about primary failure, which is often lost by conventional post-defect failure analysis. Our system monitors interfaces of component material inside the device by scanning acoustic tomography (SAT) under a power cycling test in addition to electrical and thermal condition of the device. A precursor of the failure in an early stage was indicated by the interface image much earlier than a thermal and an electrical technique. Feature identification and extraction from a series of image data by image processing efficiently pointed out the damaged site before the failure was occurred.ESREF 2015, 26th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, Oct 5-9, 2015, Centre de Congrès Pierre Baudis, Toulouse, Franc

A power cycling degradation inspector of power semiconductor devices

We have proposed a failure analysis based on a real-time monitoring of power devices under acceleration test. The real-time monitoring enables to visualize the mechanism that leads to a failure by obtaining the change of structure inside the device in time domain with high spatial resolution. In this paper, we presented a new analytical instrument based on the proposed failure analysis concept. The essential functions of this instrument are (1) power stress control, (2) non-destructive inspection and (3) water circulation. An original design power-stress control system and a customized scanning acoustic microscopy system enable us a non-destructive inspection inside the device under power cycling test. This instrument exhibits a great advantage especially to monitor failure mechanisms without having to open the module

Development of effective thermal management strategies for LED luminaires

The efficacy, reliability and versatility of the light emitting diode (LED) can outcompete most established light source technologies. However, they are particularly sensitive to high temperatures, which compromises their efficacy and reliability, undermining some of the technology s key benefits. Consequently, effective thermal management is essential to exploit the technology to its full potential. Thermal management is a well-established subject but its application in the relatively new LED lighting industry, with its specific constraints, is currently poorly defined. The question this thesis aims to answer is how can LED thermal management be achieved most effectively? This thesis starts with a review of the current state of the art, relevant thermal management technologies and market trends. This establishes current and future thermal management constraints in a commercial context. Methods to test and evaluate the thermal management performance of a luminaire system follow. The defined test methods, simulation benchmarks and operational constraints provide the foundation to develop effective thermal management strategies. Finally this work explores how the findings can be implemented in the development and comparison of multiple thermal management designs. These are optimised to assess the potential performance enhancement available when applied to a typical commercial system. The outcomes of this research showed that thermal management of LEDs can be expected to remain a key requirement but there are hints it is becoming less critical. The impacts of some common operating environments were studied, but appeared to have no significant effect on the thermal behaviour of a typical system. There are some active thermal management devices that warrant further attention, but passive systems are inherently well suited to LED luminaires and are readily adopted so were selected as the focus of this research. Using the techniques discussed in this thesis the performance of a commercially available component was evaluated. By optimising its geometry, a 5 % decrease in absolute thermal resistance or a 20 % increase in average heat transfer coefficient and 10 % reduction in heatsink mass can potentially be achieved . While greater lifecycle energy consumption savings were offered by minimising heatsink thermal resistance the most effective design was considered to be one optimised for maximum average heat transfer coefficient. Some more radical concepts were also considered. While these demonstrate the feasibility of passively manipulating fluid flow they had a detrimental impact on performance. Further analysis would be needed to conclusively dismiss these concepts but this work indicates there is very little potential in pursuing them further