Search results for "electronics"
showing 10 items of 4340 documents
Simulation of parasitic effects on Silicon Carbide devices for automotive electric traction
2020
Wide Band Gap (WBG) semiconductors are increasingly addressed towards Electric Vehicle (EV) applications, due to their significant advantages in terms of high-voltage and low-losses performances, suitable for high power applications. Nevertheless, the packaging in WBG devices represents a challenge for designers due to the notable impact that inductive and capacitive parasitic components can bring in high switching frequency regime in terms of noise and power losses. In this paper, a comparison between conventional Silicon (Si) and emerging Silicon-Carbide (SiC) power switching devices is presented. The effects of inductive parasitic effects and switching frequency are investigated in simul…
Bottle microresonator with actively stabilized evanescent coupling
2011
The evanescent coupling of light between a whispering-gallery-mode bottle microresonator and a sub-wavelength-diameter coupling fiber is actively stabilized by means of a Pound-Drever-Hall technique. We demonstrate the stabilization of a critically coupled resonator with a control bandwidth of 0.1 Hz, yielding a residual transmission of (9 \pm 3) \times 10^-3 for more than an hour. Simultaneously, the frequency of the resonator mode is actively stabilized.
Reinforcement Efficiency of Cellulose Microfibers for the Tensile Stiffness and Strength of Rigid Low-Density Polyurethane Foams
2020
Rigid low-density closed-cell polyurethane (PU) foams are widely used in both thermal insulation and structural applications. The sustainability of PU foam production can be increased by using bio-based components and fillers that ensure both enhanced mechanical properties and higher renewable material content. Such bio-based foams were produced using polyols derived from rapeseed oil and microcrystalline cellulose (MCC) fibers as filler. The effect of MCC fiber loading of up to 10 wt % on the morphology, tensile stiffness, and strength of foams has been evaluated. For estimation of the mechanical reinforcement efficiency of foams, a model allowing for the partial alignment of filler fibers…
Performances of the Fault Decoupling Device when unbalanced and multiple faults occur on distribution systems.
2005
Nowadays industrial processes are largely based on electronic devices such as programmable logic controllers and adjustable speed drives. Consequently, industrial equipments became less tolerant towards power supply disturbances. Voltage dips due to faults are surely among the worst disturbances for industrial equipments. A paper machine can be affected by disturbances of only 10% voltage drop lasting for 100 ms. A voltage dip of 75% (of the nominal voltage) with a duration shorter than 100 ms results in material loss in the range of thousands of US Dollars for semiconductors industry [1].
Design and Modeling of an Interleaving Boost Converter with Quasi-Saturated Inductors for Electric Vehicles
2020
This paper is focused on the analysis and modeling of DC-DC boost converters in interleaving configuration exploiting inductors in the quasi-saturation region. The converter is designed to optimize the power density by minimizing the size of the inductors. A simulation study for electric vehicle applications is conducted analyzing the effects of duty cycle and temperature variation on the ripple of the input current giving, moreover, information on the performances and dynamics of the converter for further implementation and optimizations.
A hardware skin-segmentation IP for vision based smart ADAS through an FPGA prototyping
2017
International audience; In this paper we presents a platform based design approach for fast HW/SW embedded smart Advanced Driver Assistant System (ADAS) design and prototyping. Then, we share our experience in designing and prototyping a HW/SW vision based smart embedded system as an ADAS that helps to increase the safety of car's drivers. We present a physical prototype of the vision ADAS based on a Zynq FPGA. The system detects the fatigue state of the driver by monitoring the eyes closure and generates a real-time alert. A new HW/SW codesign skin segmentation step to locate the eyes/face is proposed. Our presented new approach migrates the skin segmentation step from processing system (S…
Chemical design of coordination polymers and functional materials: from pore control in MOFs through spin dynamics in nanomagnets to rotaxanes in mol…
2022
El trabajo de esta tesis se enmarca en el diseño químico de polímeros de coordinación y de materiales funcionales para poder ser utilizados en el campo de los materiales moleculares. El capítulo 1 ofrece una visión de los avances más significativos en la química de coordinación, así como una introducción general de los materiales moleculares más relevantes en la actualidad. El objetivo es proporcionar al lector el conocimiento necesario para establecer las bases sobre los campos a tratar. El resto de capítulos está organizado de acuerdo con un aumento de la dimensionalidad, empezando con moléculas discretas y terminando con polímeros de coordinación. El capítulo dos describe dos estructuras…
Influence of the U3O7 domain structure on cracking during the oxidation of UO2
2010
Abstract Cracking is observed when a UO 2 single crystal is oxidised in air. Previous studies led to the hypothesis that cracking occurs once a critical depth of U 3 O 7 oxidised layer is reached. We present some μ-Laue X-ray diffraction results, which evidence that the U 3 O 7 layer, grown by topotaxy on UO 2 , is made of domains with different crystalline orientations. This observation was used to perform a modelling of oxidation coupling chemical and mechanical parameters, which showed that the domain patterning induces stress localisation. This result is discussed in comparison with stress localisation observed in thin layer deposited on a substrate and used to propose an interpretation…
Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells
2016
Thin-film solar cells suffer from various types of recombination, of which leakage current usually dominates at lower voltages. Herein, we demonstrate first a three-order reduction of the shunt loss mechanism in planar methylammonium lead iodide perovskite solar cells by replacing the commonly used hole transport layer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with a better hole-selective polyarylamine. As a result, these cells exhibit superior operation under reduced light conditions, which we demonstrate for the extreme case of moonlight irradiance, at which open-circuit voltages of 530 mV can still be obtained. By the shunt removal we also observe the VOC to dro…
Solid State Joining of Thin Hybrid Sandwiches Made of Steel and Polymer: a Feasibility Study
2020
Abstract The growing demand for more environmentally friendly vehicles has led to an increased use of light materials in the transportation industry with the aim to reduce structural weight, fuel consumption, and gas emissions, thereby boosting cost-effectiveness and recyclable properties. Complex multi-material steel-based components would allow to improve mechanical properties and minimize weight even further. In particular, new sandwich materials made by steel outer skins and a polymeric internal layer seems very promising for obtaining mechanical performance and lightness at the same time. Unfortunately, traditional welding techniques, like arc welding, laser welding, and resistance spo…