MPPT Based on Sinusoidal Extremum-Seeking Control in PV Generation

The paper analyses extremum-seeking control technique for maximum power point tracking circuits in PV systems. Specifically, the paper describes and analyses the sinusoidal extremum-seeking control considering stability issues by means a Lyapunov function. Based on this technique, a new architecture of MPPT for PV generation is proposed. In order to assess the proposed solution, the paper provides some experimental measurements in a 100 W prototype which corroborate the effectiveness of the approach

Transcriptome and Proteome Exploration to Model Translation Efficiency and Protein Stability in Lactococcus lactis

This genome-scale study analysed the various parameters influencing protein levels in cells. To achieve this goal, the model bacterium Lactococcus lactis was grown at steady state in continuous cultures at different growth rates, and proteomic and transcriptomic data were thoroughly compared. Ratios of mRNA to protein were highly variable among proteins but also, for a given gene, between the different growth conditions. The modeling of cellular processes combined with a data fitting modeling approach allowed both translation efficiencies and degradation rates to be estimated for each protein in each growth condition. Estimated translational efficiencies and degradation rates strongly differed between proteins and were tested for their biological significance through statistical correlations with relevant parameters such as codon or amino acid bias. These efficiencies and degradation rates were not constant in all growth conditions and were inversely proportional to the growth rate, indicating a more efficient translation at low growth rate but an antagonistic higher rate of protein degradation. Estimated protein median half-lives ranged from 23 to 224 min, underlying the importance of protein degradation notably at low growth rates. The regulation of intracellular protein level was analysed through regulatory coefficient calculations, revealing a complex control depending on protein and growth conditions. The modeling approach enabled translational efficiencies and protein degradation rates to be estimated, two biological parameters extremely difficult to determine experimentally and generally lacking in bacteria. This method is generic and can now be extended to other environments and/or other micro-organisms

Modelling, identification and control of a denitrifying biofilter

Biological denitrification in a fixed bed reactor is a process gaining popularity in the area of water treatment. The advent of more stringent criteria on nitrate and nitrite concentrations of treated water (along with the need to control and optimize the addition of a carbon source needed to denitrify) make the use of dynamical models able to represent the behaviour of the process not only of interest; it is also compulsory for optimizing control. The paper is concerned with the process dynamic modelling, the parameter identification and the control of the fixed bed biofilter with real-life experiments. (C) 2000 Elsevier Science Ltd. All rights reserved

Robust Gain-Scheduled Control of Switched-Mode DC-DC Converters

10.1109/TPEL.2011.2178271This paper presents a robust control synthesis framework for switched DC-DC converters. The framework is based on an LMI formulation which can be solved automatically by efficient convex optimization algorithms. The method considers parameter-dependent Lyapunov functions such that it can take into account the uncertainty of converter parameters, nonlinear dynamics (such as state-dependence), as well as transient and steady-state performances that can be imposed beforehand. The result of the proposed synthesis method is a gain-scheduled controller that guarantees stability despite the accounted nonlinear dynamics and can provide excellent performances. Two different synthesis examples are shown for a DC-DC boost converter and their performance and robustness are compared with a standard control approach as current-mode control, both in nominal and non-nominal conditions. Finally, the proposed approach is verified with experimental results

Physical dosimetric reconstruction of a radiological accident at Fleurus (Belgium) on 11 March 2006

Following a radiological accident on 11 March 2006 in an industrial irradiation facility involving one victim, a physical dosimetry was reconstructed using on site measurements and numerical simulations in order to estimate as accurately as possible and as quickly as possible the dose received and its distribution throughout the organism so that doctors may fine tune their diagnosis and prescribe the most suitable treatment. The data compiled from the experimental reconstruction resulted in a first estimation of the distribution of the dose in the victim's organism. The numerical simulations indicated a dose gradient corresponding to a factor of 2 in anteroposterior and between the pelvis and the skull. © 2007 Elsevier Ltd. All rights reserved

Anthropomorphic phantom for effective dose measurements: Feasibility numerical study and presentation of the detector development

This paper presents the current state of a project from the laboratory of ionizing radiation dosimetry of the IRSN (France) concerning the development of an instrumented anthropomorphic phantom for the direct measurement of the effective dose. Contrary to other applications fields where anthropomorphic phantoms are currently used (radiotherapy dose control or spatial studies), the main challenge of this project is to develop small detectors to place inside the phantom sensible to the low-dose rates found at workplaces. A numerical study for photon irradiation fields has proved the feasibility of such an instrument and has determined the positions of the detectors for each organ in order to correctly evaluate the effective dose. Some results of this numerical study are presented here as well as a preliminary schematic description of the prototype detector. © 2008 Elsevier Ltd. All rights reserved