4,572 research outputs found
Recent advances in efficient and reliable photovoltaic systems
No full textRenewable energies, particularly photovoltaic sources, are more often used together with the classical ones in order to have a local production that cut down the use of classical fuels and improves the reliability of the supplying. Such grid-connected applications fix mandatory constraints to power electronic converters in order to meet power quality specifications and to draw the maximum power conversion from the renewable energy into the electrical one. On the other side, stand-alone applications of renewable energies are gaining an increasing interest due to the spread of portable systems for telecommunications, remote sensing, military apparatuses, aerospace applications, etc. In the context of renewable energies, photovoltaic energy is the most promising due to the low environmental impact, the need of no maintenance after installation are encouraging perspectives in terms of costs and efficiencies. In this paper a review of the advances in the field of "Efficient and reliable photovoltaic systems" is proposed. The starting point is the Special Section entitled Efficient and reliable photovoltaic systems and published in the IEEE Trans actions on Industrial Electronics, Vol.56, No. 11, November 2009, the Guest Editors being Giovanni Spagnuolo, Giovanni Petrone, Massimo Vitelli, Remus Teodorescu and Mummadi Veerachary. Twenty-three papers were published and many of them have received up to now between ten and twenty citations. In particular, the number of citations per paper and per year for this Special Section is 6.84
Enhanced Kalman Filter-Based Identification of a Fuel Cell Circuit Model in Impedance Spectroscopy Tests
No full textModel parameters identification plays an important role in enhancing the currently available diagnosis techniques for fuel cells (e.g. electrochemical impedance spectroscopy). In this work, the dual Kalman filter (DKF) has been used for the parametric identification of a Randles circuit model. The fuel cell has been stimulated with typical EIS input signals, and the results of the identification have been validated by using the impedance spectra produced by the Fouquet impedance model. The obtained results allow to infer a functional relation between the filter settings and the input signal, thus enabling the possibility of detecting faults by inspecting the deviation of model parameters
Centralized Control in Photovoltaic Distributed Maximum Power Point Tracking Systems
No full textPhotovoltaic energy harvest in distributed maximum power point tracking systems has demonstrated to be superior to the traditional photovoltaic systems under mismatch conditions. The distributed architecture usually consists of series-connected DC/DC converters forming a string, dedicated to process the power of individual photovoltaic panels. However, the classical approach assumes an independent control of the DC/DC converters preventing them from knowing the operating condition of the other converters in the string. The adoption of centralized algorithms allows full control of the variables in distributed maximum power point tracking systems and hence further increases the energy harvest. This paper proposes a novel centralized control that matches distributed and central maximum power point tracking functions, as well as an innovative functionality that improves the dynamic performance in photovoltaic applications.info:eu-repo/semantics/publishe
One-cycle controlled power inverters
No full textOne Cycle control is a technique matching many features that are typical of the linear control methods with some others that characterise high performances non-linear control approaches. Indeed, it ensures a constant switching frequency with a high promptness and noise rejection. The One Cycle control technique has recently found applications in many fields related to the renewable energies and to the power factor control, so that the customersâ interest is increasing. In this chapter the basic elements of the One Cycle control technique are reviewed and some issues related to its wide applications are discussed. A special emphasis is given to the DC/AC single-phase conversion
Tolerance design of controllers for switching regulators
No full textAn evolutionary approach to worst case tolerance design is introduced here, with a focus on feedback compensation networks for dc-dc switching converters. Assumed that varying parameters values are uniformly distributed and uncorrelated, as provided by the worst case approach, the proposed algorithm, of general applicability, seeks for the set of nominal values and tolerances of the circuit parameters ensuring that the design constraints are met and that a user-defined circuit performance index assumes its optimal value. Design constraints, are fixed in the frequency domain, in terms of acceptability ranges of loop gain crossover frequency and phase margin, to guarantee closed loop stability and the desired dynamic performance. Resistive and capacitive compensation network's parameters values are chosen within a suitable database of couples nominal value/tolerance available on the market, while the nominal values and tolerances of the parameters of the power stage are fixed. Referring to a buck dc-dc switching regulator, two widely used different compensation network topologies are compared in terms of reliability, robustness, and cost of components. Simulation results show the wide usefulness of the proposed method in supporting designer decisions
Parameters identification of the single-diode model for amorphous photovoltaic panels
No full textThe single-diode model, which is widely used for describing the behaviour of the photovoltaic crystalline and multi-crystalline cells, requires to be properly adapted for reproducing the electrical behaviour of amorphous thin film silicon cells. As for the former case, five parameters must be identified for having a good fitting with respect to the experimental measurements or the data reported in the module data sheet. Nevertheless, due to the strong nonlinearity of the model, the fitting procedures suffer from convergency problems and are sensible to the initial guess solution. In this paper a set of explicit equations is developed in order to calculate the approximated values of the five parameters characterising the PV model. These equation have been obtained by extending, to the amorphous case, the procedure already developed for the crystalline single diode model, thus by generalising and reinforcing the validity of that approach. The new formulas have been validated by comparing the results of the proposed approach with the experimental values reported in the data sheet of some amorphous silicon panels
Experimental evaluation of a MPPT technique for electrical mobility PV applications
No full textIn this paper the performance of a maximum power point technique, which is suitable for photovoltaic applications to sustainable mobility, is documented. The approach is based on the use of one DC/DC converter per sub-section of the photovoltaic array, with a central controller that changes the duty cycle of each DC/DC converter in a way that the current injected into the battery is maximized. The control has been implemented by programming a Microchip controller through Simulink in order to have a fast prototyping. The experimental measurements, obtained during the regular driving of the vehicle, reveal the superiority of the technique in order to maximize the power harvested from the cells that are differently oriented with respect to the sun rays. The results are achieved in the frame the European Union's Horizon 2020 research and innovation program under grant agreement No. 653288 - OPTEMUS
Distributed Maximum Power Point Tracking: Challenges and Commercial Solutions
No full textU ovom članku opisane su suvremene napredne tehnike za distribuirano postizanje maksimalne snage fotonaponskih sustava. Moderne aplikacije fotonaponskih sustava u urbanom smislu i održivoj mobilnosti zahtijevaju pravilno suočavanje s nedostacima uslijed djelomičnog zasjenjenja i različitih orijentacija ćelija fotonaponskog izvora. Razmatraju se najnovije arhitekture predložene u literaturi te su objašnjene njihove prednosti i nedostaci. Naposljetku, izloženi su trenutno dostupni proizvodi na tržištu te je dan pregled njihovih karakteristika i područja primjene.In this paper the state of the art of distributed maximum power point techniques for photovoltaic systems is discussed. Modern applications of photovoltaic systems in urban context and to sustainable mobility require the proper facing of drawbacks due to partial shading and different orientations of the cells the photovoltaic source is made of. The latest architectures proposed in literature are reviewed and their points of strength and weakness are discussed. Finally, the products that are currently available on the market are presented and their fields of application and features are overviewed
L’analisi di prestazione e durata di componenti motociclistici: Parte Ia: Acquisizione dati, Parte IIa: L’analisi di prestazione, Parte IIIa: La durata
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