1,721,008 research outputs found
Special issue on reliability of new technologies for power electronics (Si and wide band gap devices, interconnections, passives, analysis and applications): Editorial
No full textLiquid Paste Interconnects on a Silicon Power Diode
No full textState-of-the-art power semiconductors use solid metal interconnects such as wire-bonding, soldering, and sintering. Thermo-mechanical stress degrades these solid metal interconnects and is the main cause of failure in power semiconductors. This letter demonstrates the use of liquid-metals (LMs), which are inherently resistant to thermo-mechanical stress, to package a silicon power diode. The manufacturing process is performed below 80 °C . The thermo-mechanical lifetime is assessed through power cycling and is shown to increase by factor of 3.3x in comparison to SAC305 solder and aluminum wirebonded diodes. In addition, the thermal resistance of LM packaged diodes shows a 9% improvement. Corrosion and pump out of the LM is thought to be the failure mode
Expected Life and Failure Model in IGBT Modules under Vibration-Induced Stress: A Case Study
No full textThis article presents a case study on a gel-filled insulated gate bipolar transistor (IGBT) module under mechanical vibration, focusing on its failure mechanism and proposing a life model. First, we used finite element analysis (FEA) with ANSYS to predict the critical stress points, which turned out to be the bond wire feet. Second, we validated these findings to a high degree through experimental tests using a vibrating chamber. In both approaches, a strong correlation is found between the failure rate and the vibration profile, where wear rate increases as one approaches the bond wires' resonance frequency. In experimental tests, all samples happened to fail at the same location, i.e., the upper side foot of terminal bond wires. This result matches the simulation predictions, as these bond wires are the ones with the lowest resonance frequency, hence the closest to the real-world vibrations. A comparison between simulation and experimental results suggest that silicone gel adds to the system a beneficial low-pass behavior that is expected to extend bond wires lifespan
Advanced power cycler with intelligent monitoring strategy of IGBT module under test
No full textPower cycling (PC) test is one of the important test methods to assess the reliability performance of power device modules related to packaging technology, in respect to temperature stress. In this paper, an advanced power cycler with a real-time VCE_ON and VF measurement circuit for the IGBT and diode, which for the wear-out condition monitoring are presented. This advanced power cycler allows to perform power cycling test cost-effectively under conditions close to real power converter applications. In addition, an intelligent monitoring strategy for the separation of package-related wear-out failure mechanisms has been proposed. By means of the proposed method, the wear-out failure mechanisms of an IGBT module can be separated without any additional efforts during the power cycling tests. The validity and effectiveness of the proposed monitoring strategy are also verified by experiments
A survey of SiC power MOSFETs short-circuit robustness and failure mode analysis
Full text linkThe aim of this paper is to provide an extensive overview about the state-of-art commercially available SiC power MOSFET, focusing on their short-circuit ruggedness. A detailed literature investigation has been carried out, in order to collect and understand the latest research contribution within this topic and create a survey of the present scenario of SiC MOSFETs reliability evaluation and failure mode analysis, pointing out the evolution and improvements as well as the future challenges in this promising device technology
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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