Power Quality Enhancement in Hybrid Photovoltaic-Battery System based on three–Level Inverter associated with DC bus Voltage Control

This modest paper presents a study on the energy quality produced by a hybrid system consisting of a Photovoltaic (PV) power source connected to a battery. A three-level inverter was used in the system studied for the purpose of improving the quality of energy injected into the grid and decreasing the Total Harmonic Distortion (THD). A Maximum Power Point Tracking (MPPT) algorithm based on a Fuzzy Logic Controller (FLC) is used for the purpose of ensuring optimal production of photovoltaic energy. In addition, another FLC controller is used to ensure DC bus stabilization. The considered system was implemented in the Matlab /SimPowerSystems environment. The results show the effectiveness of the proposed inverter at three levels in improving the quality of energy injected from the system into the grid.Peer reviewedFinal Published versio

Moments of event observable distributions and many-body correlations

We investigate event-by-event fluctuations for ensembles with non-fixed multiplicity. Moments of event observable distributions, like total energy distribution, total transverse momentum distribution, etc, are shown to be related to the multi-body correlations present in the system. For classical systems, these moments reduce in the absence of any correlations to the mo- ments of particle inclusive momentum distribution. As a consequence, a zero value for the recently introduced Phi-variable is shown to indicate the van- ishing of two-body correlations from one part, and of correlations between multiplicity and momentum distributions from the other part. It is often misunderstood as a measure of the degree of equilibration in the system

Intermediate mass excess of dilepton production in heavy ion collisions at BEVALAC energies

Dielectron mass spectra are examined for various nuclear reactions recently measured by the DLS collaboration. A detailed description is given of all dilepton channels included in the transport model UrQMD 1.0, i.e. Dalitz decays of π, η, ω, ή mesons and of the (1232) resonance, direct decays of vector mesons and pn bremsstrahlung. The microscopic calculations reproduce data for light systems fairly well, but tend to underestimate the data in pp at high energies and in pd at low energies. These conventional sources, however, cannot explain the recently reported enhancement for nucleus-nucleus collisions in the mass region 0.15GeV ≤ Me+e- ≤ 0.6GeV. Chiral scaling and ω meson broadening in the medium are investigated as a source of this mass excess. They also cannot explain the recent DLS data

Dynamic Buckling Analysis of Ductile Damage Evolution for Thin Shell With Lemaitre’s Model

Thin-shell structures are used in several fields of construction and are often exposed to severe dynamic environments, making them susceptible to dynamic instabilities. These instabilities are typically preceded by varying degrees of damage to the shell, justifying the need to incorporate this behavior in the formulation of the finite elements used. The objective of this work is to evaluate the different dynamic instability criterion in the presence of damage, afterward, evaluate the influence of this behavior on the stability of shells subjected to the dynamic excitations. The methodology of this project is essentially numerical, based on the finite element method. We are asked to program the introduction of damaging behavior and Lemaitre’s model criteria in the DYNCOQ program developed locally. To examine the results, two examples extracted from the literature were presented. The first model aimed to confirm the proper functioning of the program and the convergence of the plasticity criterion (Lemaitre's model). As for the second model, it allows us to test the dynamic instability. A comparison was made with experimental data from previously published literature, revealing a strong agreement between the calculated and experimental results. The obtained results prove the utility of considering this behavior in the shell analysis. Doi: 10.28991/CEJ-2024-010-03-012 Full Text: PD

Impact of the Boron/Epoxy patch on the Reduction of the interaction Effect Inclusion-Cracked Notch

The understanding of the materials fracture requires thorough studies of the phenomena of starting and propagation of the cracks which, in general, occur in the strong stress concentrations zones due to the geometrical and/or metallurgical effects [1]. This also makes it possible to explain the phenomenon of fracture starting and to quantify the SIF with respect to the notch geometry and crack length. In this paper an inclusion-notch interaction effect is modelled using the finite element method. The effect of the inter-distance notch-inclusion and the rigidity ratio of inclusion-matrix are highlighted with regard to the SIF evolution. The SIF evolution of a crack emanating from a notch inside the inclusion as well as the interaction with the inclusion when the notch is outside is studied. The reduction of the SIF due to the interaction crack-inclusion effect by a patch in composite is also determined

Dynamic strategy based fast decomposed GA coordinated with FACTS devices to enhance the optimal power flow

International audienceUnder critical situation the main preoccupation of expert engineers is to assure power system security and to deliver power to the consumer within the desired index power quality. The total generation cost taken as a secondary strategy. This paper presents an efficient decomposed GA to enhance the solution of the optimal power flow (OPF) with non-smooth cost function and under severe loading conditions. At the decomposed stage the length of the original chromosome is reduced successively and adapted to the topology of the new partition. Two sub problems are proposed to coordinate the OPF problem under different loading conditions: the first sub problem related to the active power planning under different loading factor to minimize the total fuel cost, and the second sub problem is a reactive power planning designed based in practical rules to make fine corrections to the voltage deviation and reactive power violation using a specified number of shunt dynamic compensators named Static Var Compensators (SVC). To validate the robustness of the proposed approach, the proposed algorithm tested on IEEE 30-Bus, 26- Bus and IEEE 118-Bus under different loading conditions and compared with global optimization methods (GA, EGA, FGA, PSO, MTS, MDE and ACO) and with two robust simulation packages: PSAT and MATPOWER. The results show that the proposed approach can converge to the near solution and obtain a competitive solution at critical situation and with a reasonable time

Fuzzy Controlled Parallel PSO to Solving Large Practical Economic Dispatch

International audienceThis paper proposes a version of fuzzy controlled parallel particle swarm optimization approach based decomposed network (FCP-PSO) to solve large nonconvex economic dispatch problems. The proposed approach combines practical experience extracted from global database formulated in fuzzy rules to adjust dynamically the three parameters associated to PSO mechanism search. The adaptive PSO executed in parallel based in decomposed network procedure as a local search to explore the search space very effectively. The robustness of the proposed modified PSO tested on 40 generating units with prohibited zones and compared with recent hybrid global optimization methods. The results show that the proposed approach can converge to the near solution and obtain a competitive solution with a reasonable time compared with recent previous approaches

Bremsstrahlung from a microscopic model of relativistic heavy ion collisions

We compute bremsstrahlung arising from the acceleration of individual charged baryons and mesons during the time evolution of high-energy Au+Au collisions at the Relativistic Heavy Ion Collider using a microscopic transport model. We elucidate the connection between bremsstrahlung and charge stop- ping by colliding artificial pure proton on pure neutron nuclei. From the inten- sity of low energy bremsstrahlung, the time scale and the degree of stopping could be accurately extracted without measuring any hadronic observables. PACS: 25.75.-q, 13.85.Q

Performance analysis of NOMA in 5G systems with HPA nonlinearities

LISBOA-01-0145-FEDER-0307095-PTDC/EEITEL/30709/2017 PTDC/EEI-TEL/30588/20 UIDB/50008/2020In this paper, we provide an analytical performance assessment of downlink non-orthogonal multiple access (NOMA) systems over Nakagami-m fading channels in the presence of nonlinear high-power amplifiers (HPAs). By modeling the distortion of the HPA by a nonlinear polynomial model, we evaluate the performance the NOMA scheme in terms of outage probability (OP) and ergodic sum rate. Hence, we derive a new closed-form expression for the exact OP, taking into account the undesirable effects of HPA. Furthermore, to characterize the diversity order of the considered system, the asymptotic OP in the high signal-to-noise (SNR) regime is derived. Moreover, the ergodic sum rate is investigated, resulting in new upper and lower bounds. Our numerical results demonstrate that the performance loss in presence of nonlinear distortions is very substantial at high data rates. In particular, it is proved that in presence of HPA distortion, the ergodic sum rate cannot exceed a determined threshold which limits its performance compared to the ideal hardware case. Monte-Carlo simulations are conducted and their results agree well with the analytical results.publishersversionpublishe