Status and Trends of Wide-Band-Gap Power Conversion

Alberto Castellazzi 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Modular Power Converter Integration based on Non-Conventional Power Switch Assembly and Interconnects

A. K. Solomon,A. Castellazzi,N. Delmonte,P. Cova 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This work presents the development of a highly integrated power switch, based on 70?m thin IGBTs and diodes rated at 600 V. The integration relies on advanced ceramic substrate technology, featuring double-etched patterned copper tracks for a fully bond-wire-less double-sided cooling packaging solution; viases are also used in the ceramic substrates for vertical current conduction, which enables the introduction of a ground-plane structure within the switch, with greatly reduced overall values of parasitic inductance. The paper also proposes an outline of system-level integration solutions for ensuring that low-inductance characteristics at switch level are not lost when interconnecting to input filter and load.

Percutaneous Radiologic Gastrostomy: A 12-Year Series

( Franco Perona ),( Giorgio Castellazzi ),( Alessandro De Iuliis ),( Laura Rizzo ) 대한소화기기능성질환·운동학회 2010 Gut and Liver Vol.4 No.s1

Background/Aims: Interventional radiologists have played a main role in the technical evolution of gastrostomy, from the first surgical/endoscopical approaches to percutaneous interventional procedures. This study evaluated the results obtained in a 12-year series. Methods: During the period December 1996 to December 2008, 254 new consecutive gastrostomies and 275 replacement procedures were performed in selected patients. All of the cases were treated by a T-fastener gastropexy and tube placement. The procedures were assessed by analyzing indications, patient selection, duration of the procedures, and mortality. Results: All 254 first gastrostomies were successful; replacement procedures were also successfully performed. One (0.2%) patient with severe neurologic disorders died after the procedure without signs of procedure-related complications, and seven (1.3%) major complications occurred (four duodenal lesions with peritoneal leakage, two gastric bleedings, and one gastric lesion). Minor complications were easily managed; three tube ruptures were resolved. Conclusions: This long-term series and follow- up showed that a group of interventional radiologist can effectively provide gastrostomy placement and long-term tube management. Percutaneous gastrostomy is less invasive than other approaches and it satisfies the needs even of high-risk patients. (Gut Liver 2010;4(Suppl. 1):S44-49)

Finite-Element Based Comparative Analysis of the Thermo-Mechanical Stresses Affecting Si and SiC Power Switches

V. Escrouzailles,A. Castellazzi,P.Solomalala,M. Mermet-Guyennet 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This work proposes a comparative study of the thermo-mechanical stress affecting a power switch when implemented with Si and SiC devices, respectively, and exposed to the same operational conditions. It employs advanced finite-element simulation analysis, adopting a dedicated procedure to implement the coupling between the thermal and mechanical domains, which require distinct numerical constructs for sensible results. The technique is applied to derive information about substrate and assembly design needs when making the transition from Si to SiC. As a case-study, a railway traction power load profile is considered.

An Approach to the Regulated Cooling of Power Systems

W.J. Choy,A. Castellazzi 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents the development of a regulation approach and its circuit implementation for the cooling of power electronics assemblies, aimed at reducing the amplitude of thermal cycles and improving overall system performance and reliability. In particular, it considers the case of forced-convection air-cooling and proposes a methodology to continuously change the speed of the fan as a function of the load conditions (i.e., the power dissipation in the active devices) to try and keep a constant value of the heat-sink temperature. The activity involves some theoretical analysis, experimental testing and design by simulation. Proof-of-concept experimental demonstration of the approach is also presented. Though dependent to some extent on the characteristics of the specific system considered, the proposed solution is suitable to be applied to a broad range of power conversion applications.

Thermal management solutions for a lightweight 3L GaN inverter

Roberto Trani,Antonio Pio Catalano,Alberto Castellazzi,Vincenzo d’Alessandro 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper presents a comparative study of different approaches and solutions to the cooling of new type highly compact flat packages for gallium nitride (GaN) transistors. The focus here is on an inverter intended for hybrid and full-electric transport applications, where optimization of the gravimetric power density is paramount. As a case-study, a 3-level active neutral point clamped (aNPC) bi-directional inverter-rectifier topology is considered. The outcomes of the investigation are manifold: optimum design of thermal vias is considered; it is highlighted that the use of a graphene layer just underneath the chip can help reduce the temperature gradient between chip and PCB and can also improve heat-conduction in subsequent layers of the assembly, by enabling a better exploitation of lateral heat-flow possibilities, too; the benefit of using a soldered DCB substrate to assist heat removal from the vias towards the heat-sink is quantified for different materials of the insulating layer (ceramic).

Accurate Mixed Electrical and Electromagnetic Model of a 6,5㎸ IGBT Module

E. Batista,J. M. Dienot,M. Mermet-Guyennet,A. Castellazzi,M. Ciappa,W. Fichtner 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

The compact model development of a 6,5㎸ field-stop IGBT module is presented. In particular, the model considers the realistic interconnection of IGBTs and anti-parallel diodes found in commercial modules, providing, next to semiconductor physics, an accurate description of electro-magnetic (EM) phenomena associated with the package and layout. A selection of simulation examples demonstrates the usefulness of the proposed solution.

Effect of Different Spray Dried Plasmas on Growth, Ileal Digestibility, Nutrient Deposition, Immunity and Health of Early-Weaned Pigs Challenged with E. coli K88

Bosi, P.,Han, In K.,Jung, H.J.,Heo, K.N.,Perini, S.,Castellazzi, A.M.,Casini, L.,Creston, D.,Gremokolini, C. Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.8

A total of 96 piglets were weaned at 19 and 13 days in Exp. 1 and 2, respectively, and allotted to one of four diets: three with different spray dried plasmas (SPs) and one with hydrolysed casein (HC). SPs were from pigs (SPP), mixed origin (SMP), and mixed origin with standardized level of immunoglobulins (SMPIG). All the diets contained 1.7% total lysine, 25% of the test protein source, 45% corn starch, 15% lactose, 2% sucrose, 7% soybean oil. At d 4 and d 2 in Exp. 1 and 2, respectively, piglets were perorally challenged with $10^{10}$ CFU E. coli K88. Growth performance, immunity, and health condition were measured for 15 days and 14 days in Exp. 1 and 2, respectively. To investigate apparent ileal digestibility and nutrient deposition, all piglets were sacrificed at d 14 in Exp. 2. In 1. 3 piglets died in HC diet and 1 in SPP diet. HC diet showed higher mortality (p<0.01) than other diets. In Exp. 2, no clinical sign of infection was detected, no difference for the content of E. coli K88 was found in feces at 4 and 6 days after the infection, and no E. coli K88 was found in the jejunum at the end of experiment. In both experiments, feed intake was lower for HC diet and ADG was 96, 106, 122 and 155 for HC, SPP, SMP and SMPIG diet, respectively (HC vs others, p<0.05; SMPIG vs other SP, p<0.01). Heal apparent digestibility of nitrogen in sacrificed piglets was higher for HC diet (p<0.05). After the challenge, K88-specific titers in saliva (Exp. 1) and in plasma (Exp. 2) were reduced in SMP and SMPIG. The piglets positive to the adhesion of the used E. coli strain to the intestinal brush borders had a significantly reduced growth (p<0.01) and a higher K88-specific IgA titer in plasma, in comparison with negative ones. This effect was independent of the diet. The data show the relevance of spray dried plasma sources and particularly of SP with standardized level of immunoglobulins for the feeding of early-weaned at the risk of infection by enterotoxigenic bacteria.