Fast Reconstitution Method (FRM) to Compute the Broadband Spectrum of Common Mode Conducted Disturbances

International audience—This paper deals with time domain simulation of common mode (CM) conducted disturbances in power electronics. This study proposes a proof of concept of a fast reconstruction method (FRM), which allows to compute the spectrum of a current based on the knowledge of a single pulse of current (i.e., the knowledge of the disturbances on a small fraction of time) and of the switching instants (i.e., the control strategy of the structure). The first parts of the paper demonstrate the reliability of the method using data measurements of a CM current generated by a PWM half-bridge converter and then by a three phase inverter. The simulation time saved thanks to the FRM is then quantified by comparing the simulation durations with or without using the FRM. In our example, the FRM allows to divide the simulation time by about 10. This analysis points out that the complex information of a CM current is contained in a small time interval. As a consequence the complete spectrum can be predicted with only a very fast simulation. The mathematical techniques developed here forecast promising reduction of simulation durations

Effects of non idealities in switching frequency modulation techniques: Application to coupled interleaved multicellular parallel converters

International audienceThis paper explores the application of the Variable Delay Frequency Modulation (VDFM) to an Interleaved Multicellular Parallel converter. VDFM is a modulation technique specially intended to reduce conducted EMI generated by parallel converters. This technique combines interleaving and frequency modulation in such a way that provides the best attenuation. On the other hand, Coupled Interleaved Multicelular Parallel Converters (CIMPC) needs a perfect current sharing among phases. In this paper we consider the effect of VDFM nonidealities on the EMI attenuation in order to consider the application of this technique to CIMPC

Using Laminated Metal Foam as the Top-Side Contact of a PCB-Embedded Power Die

International audienceThe proposed innovative manufacturing process— described in detail—uses metal foam to create a pressed contact between the top side of a PCB-embedded power die and the rest of the circuit. Initial prototypes were constructed using diodes with die dimensions of 4 mm × 6.35 mm. The prototypes were electrically characterized: the chip and contact DC and AC impedance values were measured and compared with those obtained for conventional packaging that uses bond wires. The electrical impedance of the prototypes was found to be similar to that of a state-of-the-art industrial package. Moreover, the proposed process is simple and cost-effective. Although the results presented in this letter are promising, further research is necessary to fully assess the benefits and limitations of the process

Reaction-induced embrittlement of the lower continental crust

Field observations and geophysical data reveal a causal link between brittle seismic failure and eclogitization of the lower continental crust. We present results from experimental deformation of plagioclase-rich samples at eclogite-facies conditions and quantify the link between rock rheology and the kinetics of the eclogitization reactions. The deformation was ductile both in the absence of reaction and when the progress of eclogitization was fast compared to the imposed strain rate. However, when the reaction rate was relatively slow, the breakdown of plagioclase into nanocrystalline reaction products induced a weakening that triggered seismic failure. Fluid-induced plagioclase breakdown under eclogite- facies conditions is an exothermic reaction accompanied by a negative change in solid volume. This is similar to other mineral transformations that are known to trigger transformational faulting. We demonstrate that mineral reactions lead to brittle deformation in situations where reaction rates are slow compared to the deformation rate. This reaction-induced instability may provide a generic mechanism for embrittlement at depths beyond the normal seismogenic zone

Mosaicism in autoinflammatory diseases: Cryopyrin-associated periodic syndromes (CAPS) and beyond. A systematic review

International audienceAutoinflammatory diseases (AIDs) are conditions related to defective regulation of the innate immune system. Sanger sequencing of the causative genes has long been the reference for confirming the diagnosis. However, for many patients with a typical AID phenotype, the genetic cause remains unknown. A pioneering study in 2005 demonstrated mosaicism in patients with cryopyrin-associated periodic syndromes (CAPS); the authors found somatic mosaicism in 69% of their cohort of Sanger-negative CAPS patients. We aim to address the extent to which mosaicism contributes to the etiology of AIDs and its impact on phenotype. We retrieved English-language publications reporting mosaicism in AIDs by querying PubMed with no restriction on date and we surveyed French reference centers. We provide a comprehensive clinical and genetic picture of mosaicism in AIDs. We estimate that the proportion of CAPS-like patients presenting mosaicism ranges from 0.5% to 19%. We also discuss the possible links between the proportion of mutated alleles and various clinical features. This review reevaluates the contribution of mosaic DNA variants in CAPS. Mosaicism may be more common than anticipated in other AIDs. No significant difference was demonstrated between variant allele frequency and clinical phenotype. Such knowledge has implications for the development of guidelines for genetic diagnosis, genetic counseling of affected families and effective patient care