Power loss analysis and measurement of a high efficiency DC-DC converter for EV traction AC drives

Previous works have shown the power design effectiveness of novel H-bridge-based DC-DC boost conversion structure, as well as the feasibility of real-time DC-link voltage adaptation to inverter load, in battery-supplied AC motor drives. In this paper a novel test bench has been developed, suitable for power loss measurements in high-efficiency bi-directional DC-DC converters. In order to allow for quasi-direct measurement of the lost power, the concept is to operate the converter by input current having constant module, handling alternating energy flow between two large capacitor banks at given input/output DC voltages. Accordingly, the input current reference is a low frequency (65 Hz) rectangular-wave, whose duty-cycle is regulated by suitable voltage loop due to constant module operation. Except for added large capacitor banks' losses and other secondary effects related to 65 Hz operation, the input DC power supply is shown equivalent to conversion losses at given DC working point. The results point-out the high efficiency of the conversion structure well matched with simple analytical models

Cost-effective Line Termination Net for IGBT PWM VSI AC Motor drives

The full performance of a series line termination net (LTN) has already been achieved by means of parallel ferrite-core inductors and not inductive power resistors, affecting integration and cost-effectiveness in medium-power PWM AC motor drives. A novel LTN design concept is here presented, namely IRONET, based on the exploitation of the inductor core loss as part of the wanted high-frequency LTN response. Iron cores are adopted instead of larger ferrite-core thanks to proper eddy-current density, set by design of lamination thickness and winding turns. The effective high-frequency behaviour of lossy power inductors is analysed and discussed, defining small-size R-C simple compensation. An IRONET prototype has been realised and tested for a 55 kW-rated IGBT induction motor, showing IRONET effectiveness very close to full performance even by common 0.35 mm laminations

DC-AC Conversion Strategy optimized for Battery or Fuel-Cell-Supplied AC Motor Drives

A novel DC-AC conversion strategy is presented, whcb is proposing outstanding performances in DC-supplied AC motor drives. Theoretical power system design analyses and wide experimental verifications suggested the adoption of regulated H-Bridge boost DC-DC converter stage improving overall cost and efficiency with respect to direct PWM VSI connection to variable voltage battery supply. In this work, the modulation and control strategies are investigated, suitable for the best exploitation of the power system capabilities. Through a controlled coordination between HBridge and VSI modulation patterns and control tasks, minimum PWM ripple contents and Linear voltage transfer up to six-step operation are the targets. The resulting strategy, called Cross-over Voltage Modulation, is reported for the first time together with the requested 3-OPWM enhancement called Balanced Envelopes Modulation. CVM strategy is realized and experimental tests are reported showing very satisfactory results, achieving new automotive AC motor drive quality

Expanding the spectrum of SPTLC1-related disorders beyond hereditary sensory and autonomic neuropathies: a novel case of the distinct "S331 syndrome"

Hereditary sensory and autonomic neuropathies (HSAN) encompass a group of peripheral nervous system disorders characterized by remarkable heterogeneity from a clinical and genetic point of view. Mutations in SPTLC1 gene are responsible for HSAN type IA, which usually starts from the second to fourth decade with axonal neuropathy, sensory loss, painless distal ulcerations and mild autonomic features, while motor involvement usually occur later as disease progresses

Improvement in accuracy of diagnosis of carotid artery stenosis with duplex ultrasound scanning with combined use of linear array 7.5 MHz and convex array 3.5 MHz probes: validation versus 489 arteriographic procedures1 1Competition of interest: none.Published online Mar 6, 2003.

AbstractObjective: Validity of a method to improve the accuracy of carotid artery duplex scanning was tested in comparison with arteriography.Study Design: In 489 patients who had not previously undergone arteriography, 978 carotid arteries were examined with duplex ultrasound scanning. In method A, a linear array 7.5 MHz transducer with pulsed-wave 4.7 MHz Doppler scanning was used. For the diagnosis and grading of carotid stenosis, peak systolic and end-diastolic velocity of the Doppler waves were recorded. Method B consisted of complete ultrasound imaging and color-flow mapping with a convex array 3.5 MHz transducer with pulsed-wave 2.8 MHz Doppler scanning in all patients who had previously undergone method A. Further velocity measurements were performed at the sites of stenosis. The results of methods A and B were compared with data from neurologic assessment and arteriographic studies.Results: Method B showed significantly higher diagnostic agreement with arteriography than did method A (K 95% confidence interval [CI], 0.87–0.93 vs 0.79–0.85; P < .05), and the number of mistakes in grading stenosis was significantly lower (primarily because of decreased overestimation) in patients with internal carotid kinking (>60 degrees of angulation) (P < .05), distal stenosis (>20 mm from bifurcation) (P < .01), or wide acoustic shadowing (>1 cm) (P < .01) and in those without these conditions (P < .05). Compared with arteriography, diagnostic accuracy with the new method proved higher for carotid stenoses 50% or greater, 60% or greater, 70% or greater, and 80% or greater; no statistically significant difference was found for carotid stenosis 96% or greater or for carotid occlusion. Compared with data from neurologic assessment and arteriography, method B proved more accurate than method A in designating patients for carotid endarterectomy (P = .014).Conclusions: The new method significantly improved diagnostic reliability of duplex ultrasound scanning, especially in carotid arteries with kinking, distal stenosis, or wide acoustic shadowing (32.2% of all arteries studied). In clinical practice, we suggest additional use of a lower frequency transducer in cases in which these three conditions are found or suspected at first scanning

Civiltà della Campania. Anno I, n. 1 (dicembre 1974)

A.I, n. 1 (dicembre 1974): M. Parrilli, Editoriale, P. 3 ; R. Virtuoso, Civiltà della Campania, P. 3 ; G. Galasso, Fisionomìa storica della regione, P. 6 ; Natale in Campania, P. 11, R. Causa, Cinque secoli di Presepe di, P. 12 ; M. Stefanile, I presepi d’una volta di, P. 20 ; D. Rea, L’universo mangereccio del Presepe di, P. 28 ; M. Prisco, Il presepe in provincia di, P. 34 ; B. Gatta, Una storia che non fu, P. 42 ; A. Mozzillo, Stendhal a Napoli, P. 47 ; E. Perrin, Viaggio a Cava d’un abate francese, P. 52 ; A.P. Carbone, Ravello: Villa Rufolo un paradiso per tutti, 54 ; D. Fernandez, Lettera d’amore a Napoli, P. 60 ; A. Gatto, Un mazzetto di poesie con la mia mano, 54 ; M. Parrilli, Vocazione turistica e culturale del Salernitano, P. 60 ; E. Comito, Poesia di Casertantica, P. 64 ; A. Fratta, Majorca e le Sirene, P. 67 ; V. Ricciuti, De Sica addio, P. 72 ; M. Perrotta, Il motoscafo spazzino del mare di Capri, P. 76 ; F. Canessa, Ritorna l’« opera buffa », P. 78 ; P. Gargano, Archeologia in villa, P. 83 ; E. Corsi, Per un nuovo equilibrio alberghiero, P. 86 ; F. Garbaccio, Un termalismo per tutte le stagioni, P. 88; G. Blasi, Amalfi by night, P. 90 ; A. Scelzo, La maratona Paestum-Salerno, P. 91 ; Notiziario, P. 92 ; F. De Ciuceis, Segnalazioni bibliografiche, P. 95

Civiltà della Campania. Anno II, n. 2 (febbraio-marzo 1975)

A. II, n. 2 (febbraio-marzo 1975): M. Parrilli, All’Unesco Ravello e Castellabate, P. 3 ; L’anno santo in Campania, P. 7; B. Gatta, Videre Petrum, P. 8; B. Lucrezi, Gli itinerari sacri, P. 12 ; Il Duomo di Salerno: novecento anni di fede e storia », P. 24 ; R. Causa, Santuari nel Nocerino, P. 26 ; G. Giordano, Pacem in maribus, P. 32 ; R. Virtuoso, L’ambiente e il ruolo del turismo, P. 40 ; S. Pavia, I centri storici, P. 32 ; R. Di Stefano, Villa Campolieto, P. 48 ; R. De Simone, Feste popolari, P. 56 ; E. Corsi, II riassetto di Ischia, P. 60 ; C. Nazzaro, Rosmarino col pomodoro, P. 65 ; G. Doria, Il napoletano che cammina, P. 66 ; M. Stefanile, Raffaele Viviani, P. 68 ; A. Fratta, Amedeo Maiuri: una vita per l’archeologia, P. 80 ; E. Fiore, Gli Incontri del Cinema, P. 86 ; G. Blasi, Petrosino l’antipadrino, P. 90 ; I. Santoro, Il mistero di Velia di, P. 93 ; R. Senatore, La rinascita del Borgo Scacciaventi di, P. 97 ; P. Andria, Salerno: S. Pietro a Corte, P. 100 ; U. Abundo, Amalfi sempre di, P. 102 ; V. Gramignazzi Serrone, S. Agata dei Goti, P. 106 ; Attività congressuali in Campania, P. 108 ; Notiziario, P. 10

Controlled assembly and reduction of graphene oxide networks for conductive composites

Work presented at the 2019 ACS Spring National Meeting, March 28-April 4, 2019 · Orlando, FL.Graphene has attracted enormous interest in the scientific community as the first 2D material with exceptional mechanical, electronic and thermal properties. Pristine Graphene is notoriously difficult to process for macroscale applications, to overcome this many people use graphene oxide (GO) instead. GO is water soluble and easily functionalised and so can be simply processed into various systems. GO lacks the exceptional electronic properties of graphene due to structural disorder, therefore an important area of research is on the reduction of GO, which partly restores the structure and properties of graphene. Various techniques have been developed to perform the reduction step. We report a simple approach for preparing conductive Polymer Latex-rGO composites by using a latex-assembly method. After a treatment in the oven at low T, we can reduce the GO in situ. We make use of the inherent GO properties to optimise the aqueous composite fabrication, which is scalable and adaptable, and then restore conductivity with a simple, low temperature, heating step; opening up pathways to tunable electronic composite materials on a large scale.Peer reviewe

Explosive percolation yields highly-conductive polymer nanocomposites

Explosive percolation is an experimentally-elusive phenomenon where network connectivity coincides with onset of an additional modification of the system; materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network. Nanocomposites present a structurally- and chemically-varied playground to realise explosive percolation in practically-applicable systems but this is yet to be exploited by design. Herein, we demonstrate composites of graphene oxide and synthetic polymer latex which form segregated networks, leading to low percolation threshold and localisation of conductive pathways. In situ reduction of the graphene oxide at temperatures of <150 °C drives chemical modification of the polymer matrix to produce species with phenolic groups, which are known crosslinking agents. This leads to conductivities exceeding those of dense-packed networks of reduced graphene oxide, illustrating the potential of explosive percolation by design to realise low-loading composites with dramatically-enhanced electrical transport properties