1,721,032 research outputs found
Dynamic reconfiguration of electrical connections for partially shaded PV modules: Technical and economical performances of an Arduino-based prototype
Get PDFThe partial shading phenomenon is a well known problem of photovoltaic plants. Partial shading leads to
undesirable effects such the electrical mismatch, the generation of hot spots, and generally the decrease of production of
electric energy. To mitigate the last effect, a dynamic reconfiguration of the electrical connections between modules was taken
into account. In this paper, starting from an already developed system for a small-scale photovoltaic plant reconfiguration, the
study of the economical benefits of the employment of a reconfigurator are traced. Five different incentive policies of diverse
Countries have been considered to evaluate the increase of Net Present Value of system with and without a reconfigurator
Design, implementation and experimental results of a wireless charger for E-bikes
No full textBased on the Inductive Power Transfer (IPT), the wireless energy transmission is increasingly representing an attractive solution for vehicle battery charging. Due to its high smartness, the wireless solution may be considered an interesting battery charging method for electric bicycles, as they represent light-weight and flexible means of transportation. According to the Vehicle-To-Grid (V2G) concept, the wireless power flow can occur in both the alternative directions: from the grid to the battery or in the opposite way. A Bi-Directional Inductive Power Transfer (BDIPT) system is therefore particularly convenient in the scenario of a multi-parking area. For the E-bike application, a bicycle-to-grid or a bicycle-to-bicycle energy transfer is a viable solution by means of BDIPT. In this paper, a 100W prototype of wireless battery charger for E-bikes is proposed and described
A bidirectional IPT system for electrical bicycle contactless energy transfer
No full textContactless Energy Transfer characterized by Inductive Power Transfer (IPT) is a viable solution for Electric Vehicle (EV) battery charging, giving advantages in terms of safety, comfort and automatism of the recharging operation. IPT is a smart option for the Vehicle-To-Grid (V2G) implementation as well: the EV's battery can provide power to other users, if possible and if required, in order to adequately respond to an active demand scenario. IPT shall therefore allow a Bidirectional power flow, so that it can be properly defined as Bidirectional IPT (BIPT). In this paper, a 300 W BIPT system for E-bikes is proposed and experimental results are shown as well. Considering power level and size of the proposed prototype, this BIPT system can be appropriate in a multi-parking area for E-bikes: bike-to-grid or even bike-to-bike energy transfer are viable in this way
A quasi-Z-source-based inductive power transfer system for constant current/constant voltage charging applications
Get PDFThis article proposes a quasi-Z-source (qZS)-based Inductive Power Transfer (IPT) system for Electric Vehicles (EVs) charging applications. The IPT systems use the magnetic field to transfer power between two coils wirelessly, achieving improved reliability, safety and less environmental impact. Compared to the conventional IPT system, the proposed qZS-IPT system simultaneously achieves DC/DC regulation and DC/AC conversion through a single-stage conversion, thus lowering the cost and complexity of the system. Moreover, the reliability of the system is improved thanks to the qZS network shoot-though immunity and the reduced number of switches. To ensure the battery efficient charging and long service life, the constant current/constant voltage (CC/CV) method is considered. With the proposed innovative modulation scheme, the qZS can easily change between buck and boost modes, respectively, lowering or increasing the secondary side current. A theoretical analysis is presented for system design. Simulation results based on a 25 kW (200 V/135 A) low duty EV charger are presented to verify the effectiveness of the proposed scheme. Experimental tests are performed on a 150 W scale-down prototype to validate the analysis and demonstrate the effectiveness of the proposed qZS-IPT system for CC/CV chargers
Design, implementation and experimental results of an inductive power transfer system for electric bicycle wireless charging
No full textThe use of renewable energy and the transformation of transport mode are crucial items for achieving an efficient and clean electrical mobility that allow being competitive on the market. In this context the interface between the power system and the Electric Vehicles (EVs) assumes a strategic role. Specifically, wireless energy transmission, based on Inductive Power Transfer (IPT), is an attractive solution for EVs charging. Moreover, the use of electric bicycles or kick scooters as mode of urban transport is continuously growing because they are lightweight, sustainable, easily parking, flexible and efficient transport devices. Owing to its benefits, the wireless power transfer can be considered suitable for those devices. In fact, IPT can also be exploited for Vehicle-To-Grid (V2G), where the wireless power flow can occur from battery to power grid as well. For E-bike applications, bicycle-to-grid or bicycle-to-bicycle energy transfer are viable solutions by means of a Bi-Directional Inductive Power Transfer (BDIPT). In this paper, a 300 W IPT wireless charger prototype for E-bikes is proposed. Modelling, design, simulation and experimental results of this prototype are provided. Open-loop and closed-loop tests have been performed, focusing on system behaviour for different cases of load, distance and misalignment between the coils
An Iterative Method for Bifurcation-Free Resonant Inductive Power Transfer System Design
Get PDFThe development of electric mobility makes the charging systems one of the main discussed topic. Among the different technologies, Resonant Inductive Power Transfer (RIPT) systems are in deep study. Several aspects, including the choice of coils, the compensation network and the bifurcation phenomenon are necessary for a proper design of the system. In this paper an iterative method for bifurcation-free RIPT system design is provided as a valid solution to the need of accurate models requiring low computational efforts
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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