A simple maximum power point tracking based control strategy applied to a variable speed squirrel cage induction generator

This paper presents a comprehensive modelling and control study of a variable speed wind energy conversion system based on a squirrel-cage induction generator (SCIG). The mathematical model of the SCIG is derived in Park frame along with the indirect field oriented control (IFOC) scheme based on a proportional and integral speed controller. A simple maximum power point tracking strategy is used to determine the optimal speed under variable wind speed conditions which is then used as the reference in the IFOC scheme. Power flow between the supply and the inverter is regulated via simultaneous control of the active and reactive currents of the grid and the DC link voltage. The simulation results show that the proposed control technique is able to maximise the energy extracted from the wind during the simulation scenarios considered. The results also demonstrate good transient response characteristics in the decoupled real and reactive powers.Peer reviewedFinal Accepted Versio

Effect of endophytic bacteria from Algerian prickly pear roots on wheat under drought stress

Cactus are among the most drought tolerant plants. As Opuntia is able to grow under the stress of drought, this study aims to check if endophytic bacteria isolated from cactus roots have beneficial potential for crops such as wheat during drought. Two endophytic bacterial isolates were isolated from the roots of the cactus and screened for their plant growth promoting characteristics, such as N-free growth and auxin production. These bacteria have demonstrated their potential to promote the growth of durum wheat under in-vitro conditions and have been identified as Pseudomonas putida and P.brassicacearum, following the sequencing of the 16S rRNA gene and phylogenetic analysis, and significantly improved growth parameters such as seeding length compared to the unobstructed control. After 05 days of contact of the two bacteria, P.putida and P.brassicacearum, with sprouted wheat seeds, a root growth rate of (39.88% and 62.14%, respectively) was recorded. The same effect on the growth of wheat roots is caused by the volatile substances of these bacteria deposited separately, with a rate of (53.30% and 24.18%) respectively. Symptoms of drought stress were visibly reduced on seedlings inoculated with P.putida and P.brassicacearum bacteria, a result supported by a growth rate of root parameters in length (260.83% and 179.60%), surface (21.98% and 60.17%) and scope (59.46% and 62.67%), respectively. This work opens up many perspectives for the characterization and selection of endophyte bacteria of under-used drought-tolerant species such as cacti for the improvement of the growth of field crops. These results promote the deployment of Pseudomonas sp as an effective biofertilizer in wheat

Evaluation of the antagonistic potential of bacterial strains isolated from Algerian soils for the biological control of phytopathogenic fungi

Antagonistic bacteria contribute to the management of plant diseases by stimulating the natural defenses in the host and/or by ensuring direct biocontrol of the aggressors. The objective of this work was to isolate, identify and evaluate (in vitro) various Bacillus spp. for their potential to control phyopathogenic fungi. Selection of the 40 strains of Bacillus previously isolated from the soil in various areas of western Algeria was carried out by direct confrontation on the mycelial growth of four phytopathogens (Fusariumoxysporumf.splycopersici, Alternaria tenuis , Phytophthorainfestans, Ascochytapisi). This strategy involved using the antagonistic potential of microorganisms found in the plant environment in Algeria. The second part of this work consisted of the characterization and identification of tested strainsThe identification of the selected strains was carried out by biochemical tests. The results obtained showed that at the end of the fifth day, the most promising isolates showed antifungal activity and reached an inhibition rate of the mycelial growth of phytopathogenic fungi, respectively, F. oxysporumf. splycopersici 75%, A. tenuis 80%, P. infestans 83.30%, Ascochytapisi 67%. The potential antagonist of Bacillus tested in vitro by direct confrontation against 04 phytopathogenic fungi showed that all strains of Bacillus decreased fungal mycelial growth. Two strains of Bacillus B30 and B41 were found to have the most efficacy against Fusarium oxysporum f.sp. lycopersici, Alternaria tenius, Phytophtora infestans et Ascochyta pisi, with an inhibition rate of  65.25 and 72.25% respectively These results demonstrate that Bacillus sp. presenteds a potential for biological control. However, it is important to understand the mechanisms implemented by these bacteria to develop effective protection strategies

Biometrics analysis of the stem fibers of some local Algerian plant species

Studying the biometric characteristics of the stems of plant species has been of great interest to researchers in the wood and paper industry. The use of plant fibers has been widespread in the fields of composites, buildings, insulation, plastics and automobiles. The present study aimed to investigate the biometric characteristics of the stem fibers of local Algerian plant species, viz. Group 1 (Lygeum spartum and Stipa tenacissima), Group 2 (Linum usitatissimum in the greenhouse and Linum usitatissimum in natural conditions), Group 3 (Retama monosperma and Retama raetam) and Group 4 (Phoenix dactylifera and Ricinus communis). The extraction process was carried out using 1 M NaOH at 60 °C for 48 hours, and the fiber length was calculated for all the species using a micrometer. The fiber length of stems of all the species ranged from 0.36 to 5.18 mm. Then, the difference between each of the two species was approximated using Student's test. The results obtained showed that the t value ranged from 0.50 to 1.79 for Groups 4 and 1, respectively. There was no significant difference between them. These results suggest that these species are promising raw materials for paper production due to their adequate fibre length

Dual Robust Control of Grid-Connected DFIGs-Based Wind- Turbine-Systems under Unbalanced Grid Voltage Conditions

In this chapter, a comparative analysis is made for doubly-fed induction-generator (DFIG) low-voltage ride-through (LVRT) solutions. It is supposed to improve the LVRT capability of DFIG under unbalanced grid voltage conditions by hardware or software solutions. Therefore, this chapter proposes a low-cost software LVRT solution based on an efficient control scheme of DFIG driven by a wind turbine. The proposed control scheme is based on dual-sequence decomposition technique and Lyapunov-based robust control (RC) theory. Under an unbalanced grid voltage conditions, the proposed control strategy not only eliminates effectively the oscillations of the active and reactive powers exchanged between the generator and the grid but also achieves the symmetrical and sinusoidal grid currents injection. Simulation analysis under MATLAB®/Simulink® has been carried out on a 1.5 MW DFIG-based wind-turbine-systems, and the results are presented and discussed to demonstrate the feasibility and the efficiency of the control strategy for a grid-connected application under unbalanced voltage supply. The proposed dual control scheme is shown to be able to successfully mitigate torque, stator power and currents pulsations as compared with the conventional vector control based on the single control scheme

Simultaneous plasticization and blending of isolated soy protein with poly(butylene succinate-co-adipate)

International audienceAgrarian proteins, due to their good film forming properties, moderate cost, and biodegradable nature, have been extensively studied to develop affordable packaging materials. However, when compared to conventional polymers, isolated proteins based polymers have poor mechanical and barrier properties. Blending with others polymers seems to be a viable option to overcome these issues. The present work focuses on the preparation of isolated soy protein (ISP) / poly[(butylene succinate)-coadipate] (PBSA) blends with different ratios by extrusion and injection moulding using glycerol and water mixture as plasticizer. PBSA is bio-based, biodegradable, and its relatively low melting point is compatible with the processing temperature of ISP. Two different processing strategies were used and compared for the preparation of blends. In the novel single step approach, ISP, plasticizers (glycerol and water) and PBSA are dry mixed and extruded all together in a co-rotating twin-screw extruder. In the regular two-step approach, plasticized protein is prepared by extrusion of ISP with a glycerol/water mixture, followed by a second extrusion step of plasticized protein with PBSA. Prepared blends were characterized for their morphology, thermal, dynamic mechanical and mechanical properties. The mechanical properties of the blends prepared by single step process are roughly similar to those produced by two-step process; this indicates the efficiency of one-step melt processing of PBSA with isolated soy protein involving plasticization, denaturation, melt-melt mixing and morphology development in the extruder, this compounding method being moreover less time consuming

Enhanced Power Quality in Single-Phase Grid-Connected Photovoltaic Systems: An Experimental Study

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).The main aim of the research work presented in this paper consists of proposing an effective control scheme for a grid-connected single-phase photovoltaic (PV) system to enhance not only the power quality at the point of common coupling (PCC) but also to operate with a maximum power point tracking (MPPT) controller. Moreover, an orthogonal signal generator (OSG) module for effective grid synchronization, a current reference generation controller, and a PWM generating block have also been designed and included in this paper. The proposed control strategy allows the MPPT controller to switch to faulty mode and maintains the voltage according to network requirements using an adaptive neuro-fuzzy inference system (ANFIS)-based control whenever a fault occurs at the PCC. The performance of the analyzed control strategy, which is based on the static compensation of the DC-link voltage fluctuations in a grid-connected inverter powered by PV, is further explored through simulations in MATLAB, and the results are included in this paper. Moreover, the control scheme is implemented experimentally using a dSPACE DS 1104 control board and then assessed on a small laboratory-scale single-phase PV system that is subjected to some fault scenarios. The simulation and experimental results have shown improved power quality and robustness against grid fluctuations, resulting in better dynamic performance.Peer reviewe

Heavy metals and aluminium intake from stored canned tomato, sardines and tuna in Algeria

This study assessed heavy metals intake and their impacts on healthcare in Algeria. Peculiar attention was given to heavy metals found in largely consumed canned foods in Algeria such as double concentrated tomato, tuna crumbs and sardines. Chemical analyses of the metal and aluminium containers (foil, tray) were performed by X-Ray Fluorescence (XRF) and EDS spectrometry (Energy Dispersive Spectrometry). The determination of the trace metal content in canned food (element metal trace EMT) was achieved by Atomic Absorption Spectrometry (AAS). The approach proposed in this study aimed to highlight the interaction of the product and packaging material, and thus to identify and quantify heavy metals traces that were able to undergo specific or overall migration to food. The morphology of the contact surface food / packaging was observed by Scanning Electron Microscope (SEM) and showed a slight degradation of the base metal (Black Iron).  There was an obvious increase in EMTs during tuna, sardines and tomatoes storage and artificial aging. A special interest was given to cooking modes using aluminium foil and trays.  ‎‎The respective dosages of aluminium, in baked food (fresh tuna) were obtained. Specific Aluminium migration was noticed and was strong for the flame cooking mode

The enerMENA Meteorological Network – Solar Radiation Measurements in the MENA Region

International audienceFor solar resource assessment of solar power plants and adjustment of satellite data, high accuracy measurement data of irradiance and ancillary meteorological data is needed. For the MENA region (Middle East and Northern Africa), which is of high importance for concentrating solar power applications, so far merely 2 publicly available ground measurement stations existed (BSRN network). This gap has been filled by ten stations in Morocco, Algeria, Tunisia, Egypt and Jordan. In this publication the data quality is analyzed by evaluating data completeness and the cleanliness of irradiance sensors in comparison for all of the stations. The pyrheliometers have an average cleanliness of 99.2 % for week-daily cleaning. This is a 5 times higher effort than for Rotating Shadowband Irradiometer (RSI) stations which even have a slightly higher average cleanliness of 99.3 % for weekly cleaning. Furthermore, RSI stations show a data completeness of 99.4 % compared to 93.6 % at the stations equipped with thermal sensors. The results of this analysis are used to derive conclusions concerning instrument choice and are hence also applicable to other solar radiation measurements outside the enerMENA network. It turns out that RSIs are the more reliable and robust choice in cases of high soiling, rare station visits for cleaning and maintenance, as usual in desert sites. Furthermore, annual direct normal and global horizontal irradiation as well as average meteorological parameters are calculated for all of the stations

Analysis of wavelet controller for robustness in electronic differential of electric vehicles: an investigation and numerical developments

In road transportation systems, differential plays an important role in preventing the vehicle from slipping on curved tracks. In practice, mechanical differentials are used, but they are bulky because of their increased weight. Moreover, they are not suitable for electric vehicles, especially those employing separate drives for both rear wheels. The electronic differential constitutes recent technological advances in electric vehicle design, enabling better stability and control of a vehicle on curved roads. This article articulates the modeling and simulation of an electronic differential employing a novel wavelet transform controller for two brushless DC motors ensuring drive in two right and left back driving wheels. Further, the proposed work uses a discrete wavelet transform controller to decompose the error between actual and command speed provided by the electronic differential based on throttle and steering angle as the input into frequency components. By scaling these frequency components by their respective gains, the obtained control signal is actually given as input to the motor. To verify the proposal, a set of designed strategies were carried out: a vehicle on a straight road, turning right and turning left. Numerical simulation test results of the controllers are presented and compared for robust performance and stability