An efficient scanning algorithm for photovoltaic systems under partial shading

This paper proposes a new technique of maximum power point tracking (MPPT) for a photovoltaic (PV) system connected to three phase grids under partial shading condition (PSC), based on a new combined perturb and observe (P&O) with scanning algorithm. This new algorithm main advantages are the high-speed tracking compared to existing algorithms, high accuracy and simplicity which makes it ideal for hardware implementation. Simulation was carried on MATLAB/Simulink. Results showed the effectiveness in speed and accuracy of our algorithm over the existing ones either during standard condition (STC) or PSC. Furthermore, conventional direct power control (DPC) was applied to synchronize successfully the injected power with the grid, which makes our algorithm global and works efficiently under severe conditions

L’impact des infrastructures de transport sur la compétitivité mondiale : une analyse en coupe transversale

The objective of transport infrastructure provision is to reduce the distance effect and transport costs and is therefore a key element for improving competitiveness. Thus, this paper aims to assess the effect of transport infrastructure on national competitiveness depending on the level of evolution of other factors affecting the economy. Thus, to carry out this study, we use multiple regression model and cross-sectional data for 137 countries. This econometric methodology was adopted to estimate the relationships between the variables. The focus is first on the relationship between national competitiveness and ten independent variables, the same as the World Economic Forum pillars. Next, we proceed to determine the relationship between the quality of the overall infrastructure and its four components. The data set is collected from the Global Competitiveness Report of the year 2017-2018. The results confirmed that national competitiveness is impacted by the level of institutional development and seven other factors, including transportation infrastructure. The main bottlenecks that hinder the development of the national economy were identified. The final goal is to present academics and policy-makers with a relevant means of implementing appropriate economic strategies. The main suggestion is that the economic competitiveness of a country can be improved not only through the development of transport infrastructure but also through the implementation of several actions affecting the potential sectors. Keywords: Transport infrastructure, national competitiveness, cross-section, global competitiveness index JEL Classification: H00, H54 Paper type: Empirical researchL’objectif de la mise en place des infrastructures de transport est la réduction de l’effet de distance et des coûts de transport et constitue par conséquent un élément clé pour l’amélioration de la compétitivité. Ainsi, cet article se fixe pour objectif l’évaluation de l’effet produit par les infrastructures de transport sur la compétitivité nationale selon le niveau d’évolution, d’autres facteurs impactant l’économie. Ainsi, pour mener cette étude, nous utilisons le modèle de régression multiple et données en coupe transversale pour 137 pays. Cette méthodologie économétrique a été adoptée pour l’évaluation des relations entre les variables. L'accent étant mis en premier lieu sur le lien entre la compétitivité nationale et dix variables indépendantes, les mêmes que les piliers du Forum économique mondial. Ensuite, nous procédons à la détermination de la relation entre la qualité de l'infrastructure globale et ses quatre composantes. L’ensemble des données est recueilli à partir du rapport sur la compétitivité globale de l’année 2017-2018. Les résultats ont confirmé que la compétitivité nationale est impactée par le niveau de développement institutionnel et par sept autres facteurs, notamment l'infrastructure de transport. Les principaux goulots qui entravent le développement de l'économie nationale ont été identifiés. Le but final est de présenter aux académiques et décideurs politiques un moyen pertinent pour la mise en œuvre des stratégies économiques convenables. La principale suggestion retenue est que la compétitivité économique d’un pays peut être améliorée non seulement par le développement des infrastructures de transport, mais aussi par la mise en place de plusieurs actions touchant les secteurs potentiels. Mots clés : Infrastructure de transport, compétitivité nationale, coupe transversale, index de compétitivité globale. Classification JEL :  H00, H54 Type de l’article : Recherche appliqué

Integral Backstepping Control for Maximum Power Point Tracking and Unity Power Factor of a Three Phase Grid Connected Photovoltaic System

This paper presents a robust control strategy for a grid connected photovoltaic system with a boost converter by using an integral Backstepping method based on a nonlinear state model, which guarantees the Lyapunov stability of the global system. The system has tracked precisely the maximum power point, with a very fast response and the unit power factor has been observed under different atmospheric conditions. Moreover, the best advantage of the controller is that it’s a good corrector of the grid perturbation and system parameter disturbance. The simulation result has demonstrated the performance of this strategy

Efficient Control of a Three Phase Grid Connected PV System

This paper presents a new control strategy of a photovoltaic system, which consists of a photovoltaic generator PVG coupled to a three phase load and three phase grid by a three phase voltage source inverter VSI without DC-DC converter. The controller is designed by using Backstepping method based on d-q transformation of a new model of the global system. The main goals of this control strategy are to achieve the maximum power point MPPT with very good precision and the unity power factor in level of the grid power flow. Mathematical analysis demonstrate the asymptotic stability of the controlled system and simulation results proved that the controller has achieved all the objectives with high dynamic performance in presence of atmospheric condition changes. Moreover, the proposed controller shows a very good robustness under system disturbance, which presents the most important advantage of this controller compared to the other control strategies. Furthermore, this controller can operate with a high efficiency with any kind of the load

Decay Properties for Transmission System with Infinite Memory and Distributed Delay

We consider a damped transmission problem in a bounded domain where the damping is effective in a neighborhood of a suitable subset of the boundary. Using the semigroup approach together with Hille–Yosida theorem, we prove the existence and uniqueness of global solution. Under suitable assumption on the geometrical conditions on the damping, we establish the exponential stability of the solution by introducing a suitable Lyapunov functional