1,721,709 research outputs found
La costruzione del dispositivo terapeutico : artefatti, garanti metapsichici e rinegoziazione dell’identità in migrazione
No full textComputer-Aided Simulation and Modeling of Power Electronics Time-Variant Networks
No full textSmall signal linear models are widely applied for design and control optimization of power electronic circuits. A wise substitution of non-linear time-variant circuits with linear models simplifies the computational burden without affecting too much the accuracy. Furthermore, if the substitution is performed automatically the design speed can be significantly shortened.
This paper deals with FREDOMSIM, a software tool able to support the automatic extraction of small signal models for power electronics applications.The theoretical bases, operating principles, and modeling trade-offs of this program are illustrated and its effectiveness is shown through an example of application to a DC/DC converter. Integration with commercial packages such as SPICE, MATLAB/SIMULINK provides a complete modeling environment easy to approach for a designer
Automatic Modelling of PWM DC-DC Converters
No full textDifferent small-signal models are available for describing the dynamics of pulse width modulators (PWM) dc-to-dc converters. Discrete time models reach the best compliance in real life situations. Some converter control modes, in particular phase shifting, provide advantages of modeling in discrete time. On the other hand, the burden of getting such exact models is often tedious. Nowadays, automatic tools are available that can provide the state-space model in discrete time of any PWM dc-dc converter switching at constant frequency. The authors claim that the use of these tools is advisable for the analysis and control optimization of switching power supplies. To support their opinion, this letter refers to a new, very accurate small-signal model of a phase-shifting converter which has been published recently. Its excellent performance, as well as the difficulties of the derivation procedure, are compared with the precise forecasts and the short processing time of an automatic modeling tool. The paper concludes in favor of automatic modeling
Dynamic virtual test of power electronics converters
No full textThe exigency of a rapid prototyping of power converters represents an important issue for the power electronics market and pushes the designer toward the search of software tools able to depict the static and dynamic behavior of the electrical circuits. The availability of reliable analysis tools open the possibility to their use not only for the design but also for the test of the converters in circumstances not easily replicable in laboratory (f.i. possible disruptive condition like short circuit or interconnection with other not easily available systems) or for the forecast of their behavior in operating conditions far from the nominal ones. The paper discusses the methodology used for the dynamic modelization of constant frequency switching DC-DC converters. The automatic software tool, FREDOMSIM, makes use of a state space discrete time approach to provide a complete dynamic description of power cells. Examples of tests of different phase-shifted DC-DC converters, made by means of the virtual dynamic performance environment, are presented
Analisi teorica e validazione sperimentale di un modello per smorzatori idraulici passivi
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Disponibilità e gestione partecipata della risorsa idrica come fattore di sviluppo locale: il caso lombardo
No full textInformatica e processo alimentare
Full text linkmessa a punto e collaudo di un sistema di documentazione on-line per il settore alimentare basato su flow charting interattivo, WEB service e fruibile mediante Internet shotcod
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