Hardware-in-the-loop implementation of single- and dual-phase shift control for dual active bridge converters in EV applications

Isolated DC-DC converters play a significant role in fast charging and maintaining the variable output voltage for EV applications. This study aims to investigate the different Isolated DC-DC converters for onboard and offboard chargers, then, once the topology is selected, study the control techniques and, finally, achieve a real-time converter model to accomplish Hardware-In-The-Loop (HIL) results. Among the different isolated DC-DC topologies, the Dual Active Bridge (DAB) converter has the advantage of allowing bidirectional power flow, which enables operating in both Grid to Vehicle (G2V) and Vehicle to Grid (V2G) modalities. Recently, DAB has been used in the offboard chargers for high voltage applications due to SiC and GaN MOSFETs; this new technology also allows the utilization of higher switching frequencies. By empowering soft switching techniques to reduce switching losses, higher switching frequency operation is possible in DAB. There are four phase shift control techniques for the DAB converter. They are Single Phase shift, Extended Phase shift, Dual Phase shift, Triple Phase shift controls. This thesis considers two control strategies; Single-Phase, and Dual-Phase shifts, to understand the circulating currents, power losses, and output capacitor size reduction in the DAB. Hardware-In-The-Loop (HIL) experiments are carried out on both controls with high switching frequencies using the PLECS software tool and the RT box supporting the PLECS. Root Mean Square Error is also calculated for steady-state values of output voltage with different sampling frequencies in both the controls to identify the achievable sampling frequency in real-time. DSP implementation is also executed to emulate the optimized DAB converter design, and final real-time simulation results are discussed for both the Single-Phase and Dual-Phase shift controls.

Wind analysis of the Messina Strait Bridge design project proposal with stabilizing cables

A new study on suspension bridges has been prompted by the big disaster of the Tacoma Narrow Bridge at half its design speed. The aerodynamic instability of long-span bridges has been studied using wind tunnel tests. As a result of improved aerodynamic performance from the geometrical configuration of the bridge deck, the aerodynamic criteria for suspension and cable-stayed bridges have become well established in recent years, thereby allowing longer bridge spans to be developed. Although the Messina Strait Bridge has yet to be constructed, we are looking forward to evaluating the impact of different deck cross-sections on both aerodynamic stability and cost reduction. To further improve the aerodynamic characteristics of long-span suspension bridges, an optimized multi-box bridge deck model with two side decks for traffic lanes, two middle railway decks, and three gaps separating them has been proposed aerodynamic performance has been experimentally verified. 1:80 scale wind tunnel tests have been conducted. According to the current MIDAS Model, the first torsional and the first vertical frequency ratios are 1.27787 and 1.36[1] respectively. It is the torsional/vertical frequency ratio, combined with the deck aerodynamic properties, that determines the wind response properties of the bridge for the most dangerous possible form of aeroelastic instability. The classic flutter is caused by the coupling of torsional and vertical modes. Stabilizing cables to the deck could be a solution to this classic flutter by reducing lateral displacement of the deck and increasing frequency ratios. Stabilizing cables will be installed on the deck in three different orientations: vertical, inclined, and horizontal, with diameters of 80 cm, 60 cm, and 40 cm in each orientation respectively. An overview of the research undertaken on this topic will be presented, as well as the most important findings.

Investigating the origin of radio emission from the intra-cluster bridge A399-A401

Radio bridges are a newly observed class of phenomena, they are large scale filamentary structures that span between pairs of clusters in a pre-merger phase. In my Thesis, starting from the observed synchrotron emission in the bridge A399-A401, I apply a Fermi I shock re-acceleration model under different conditions to the bridge. The purpose of my work is to check the likelihood of the above mentioned model. In particular the Inverse Compton emission that the model predicts is above the current observational constraints on Inverse Compton for the bridge A399-A401, this means that a Fermi I re-acceleration model is unlikely to describe the emission from the bridge, while a Fermi II turbulent re-acceleration model could still explain the origin of the emission in the bridge.

Loading and damage modelling for an integrated SHM system of a prestressed concrete railway bridge in Naples

The thesis explores recent technology developments in the field of structural health monitoring and its application to railway bridge projects. It focuses on two main topics. First, service loads and effect of environmental actions are modelled. In particular, the train moving load and its interaction with rail track is considered with different degrees of detail. Hence, results are compared with real-time experimental measurements. Secondly, the work concerns the identification, definition and modelling process of damages for a prestressed concrete railway bridge, and their implementation inside FEM models. Along with a critical interpretation of the in-field measurements, this approach results in the development of undamaged and damaged databases for the AI-aided detection of anomalies and the definition of threshold levels to prompt automatic alert interventions. In conclusion, an innovative solution for the development of the railway weight-in-motion system is proposed.

Modeling and Design of Phase Shifted Full Bridge Isolated DC-DC ZVS Converter with Peak Current Mode Control

Nowadays, there is a boom in the use of electrification. Electric vehicles are gaining interest worldwide due to various factors, including climate and environmental awareness. In this thesis, a step-down isolated power supply for electric tractors is investigated, specifically the phase-shifted full-bridge (PSFB) DC-DC with synchronous rectification and zero-voltage switching (ZVS). This converter was selected for its high-power capacity with high efficiency. A 3500 W PSFB converter with peak current control (PCCM) is designed and modeled in MATLAB. The input voltage range is from 550 V to 820 V and the output voltage range is limited to 9 V to 16 V with a maximum output current of 250 A. All components were commercially designed and selected, including magnetics for the high-frequency transformer and inductors, taking into account loss calculations. Zero voltage switching for the lagging leg is achieved at 13% to 100% load. The proven efficiency of the converter is around 90

BIM-FEM model interoperability for the design of a prestressed concrete bridge deck

In questa tesi ho analizzato il passaggio dall'ambiente BIM a quello FEM di un impalcato da ponte a travata precompressa, identificando criteri e applicando una metodologia che hanno consentito lo sviluppo di un modello FEM utilizzabile per l'analisi strutturale. Nella tesi si descrive l'opera e il suo dimensionamento, con l'analisi statica e le verifiche strutturali eseguite sia a mano sia sul modello in ambiente FEM importato dall'ambiente BIM. Oltre a ciò, viene modellata l'opera nella sua interezza ed inserita in un contesto reale. La tesi discute l'interoperabilità tra i due software evidenziando vantaggi (modello geometrico di partenza in ambiente FEM, trasferimento di informazioni inserite in ambiente BIM, riduzione dei tempi di modellazione e inserimento proprietà dei materiali e caratteristiche degli oggetti, inserimento armature di precompressione) e criticità (implementazione manuale di alcuni elementi nel modello geometrico, perdita di alcune informazioni, definizione di alcuni parametri, limitata interoperabilità FEM-BIM) della metodologia applicata.

Analysis, Design, and Hardware-in-the-Loop Validation of Multi-Active Bridge Converters

This master's thesis investigates different aspects of Dual-Active-Bridge (DAB) Converter and extends aspects further to Multi-Active-Bridges (MAB). The thesis starts with an overview of the applications of the DAB and MAB and their importance. The analytical part of the thesis includes the derivation of the peak and RMS currents, which is required for finding the losses present in the system. The power converters, considered in this thesis are DAB, Triple-Active Bridge (TAB) and Quad-Active Bridge (QAB). All the theoretical calculations are compared with the simulation results from PLECS software for identifying the correctness of the reviewed and developed theory. The Hardware-in-the-Loop (HIL) simulation is conducted for checking the control operation in real-time with the help of the RT box from the Plexim. Additionally, as in real systems digital signal processor (DSP), system-on-chip or field programmable gate array is employed for the control of the power electronic systems, and the execution of the control in the real-time simulation (RTS) conducted is performed by DSP.

Un bridge tra sistemi di bordo e di terra per prevenire minacce informatiche alla sicurezza delle infrastrutture critiche dei trasporti ferroviari

Il progetto di tesi nasce dall’interesse e dalla passione verso il mondo della Cybersecurity, che da sempre segna il mio percorso accademico e di vita, ma che durante questo ultimo anno di università ha avuto particolare rilevanza. Il progetto è stato svolto con il supporto e la supervisione del team Railway dell’azienda ALTEN Italia presso la sede di Bologna. Il lavoro di tesi mira allo sviluppo di un componente software che rappresenta un livello aggiuntivo di sicurezza nella comunicazione tra sistemi di bordo e di terra. In particolare, il progetto si pone come obiettivo la creazione di un Bridge, ovvero un componente software indipendente e configurabile che si interfaccia sia con il client che con il server, con lo scopo di garantire autenticità e cifratura dei messaggi scambiati tra le due entità. Inoltre, la potenza del Bridge sta nel fatto che nasce come possibile soluzione ai problemi di sicurezza informatica in ambito ferroviario, ma la sua applicabilità può essere estesa anche ad altri settori in cui sia presente una comunicazione client/server da rendere sicura. Infatti, tale software risulta particolarmente flessibile e adattabile, attraverso l’impostazione a priori di parametri di configurazione, in base al tipo di comunicazione che si desidera implementare tra le due entità. Per questo motivo, si ritiene che la forza del progetto sia la possibilità di fornire una soluzione software per proteggere l’infrastruttura critica dei trasporti ferroviari da eventuali minacce informatiche, ma anche la capacità adattiva del Bridge, in grado di svolgere le sue funzioni di sicurezza in un ampio ventaglio di ambiti di applicazione.

RED-Bridge: A Multiprotocol Tool Prototype for IoT Sensors

The IoT is growing more and more each year and is becoming so ubiquitous that it includes heterogeneous devices with different hardware and software constraints leading to an highly fragmented ecosystem. Devices are using different protocols with different paradigms and they are not compatible with each other; some devices use request-response protocols like HTTP or CoAP while others use publish-subscribe protocols like MQTT. Integration in IoT is still an open research topic. When handling and testing IoT sensors there are some common task that people may be interested in: reading and visualizing the current value of the sensor; doing some aggregations on a set of values in order to compute statistical features; saving the history of the data to a time-series database; forecasting the future values to react in advance to a future condition; bridging the protocol of the sensor in order to integrate the device with other tools. In this work we will show the working implementation of a low-code and flow-based tool prototype which supports the common operations mentioned above, based on Node-RED and Python. Since this system is just a prototype, it has some issues and limitations that will be discussed in this work.

Minimal Invasive Ostheosintesis For Treatment Of Diaphiseal Transverse Humeral Shaft Fractures.

To evaluate patients with transverse fractures of the shaft of the humerus treated with indirect reduction and internal fixation with plate and screws through minimally invasive technique. Inclusion criteria were adult patients with transverse diaphyseal fractures of the humerus closed, isolated or not occurring within 15 days of the initial trauma. Exclusion criteria were patients with compound fractures. In two patients, proximal screw loosening occurred, however, the fractures consolidated in the same mean time as the rest of the series. Consolidation with up to 5 degrees of varus occurred in five cases and extension deficit was observed in the patient with olecranon fracture treated with tension band, which was not considered as a complication. There was no recurrence of infection or iatrogenic radial nerve injury. It can be concluded that minimally invasive osteosynthesis with bridge plate can be considered a safe and effective option for the treatment of transverse fractures of the humeral shaft. Level of Evidence III, Therapeutic Study.

Anatomical Study Of Minor Alterations In Neonate Vocal Folds.

Minor structural alterations of the vocal fold cover are frequent causes of voice abnormalities. They may be difficult to diagnose, and are expressed in different manners. Cases of intracordal cysts, sulcus vocalis, mucosal bridge, and laryngeal micro-diaphragm form the group of minor structural alterations of the vocal fold cover investigated in the present study. The etiopathogenesis and epidemiology of these alterations are poorly known. To evaluate the existence and anatomical characterization of minor structural alterations in the vocal folds of newborns. 56 larynxes excised from neonates of both genders were studied. They were examined fresh, or defrosted after conservation via freezing, under a microscope at magnifications of 25× and 40×. The vocal folds were inspected and palpated by two examiners, with the aim of finding minor structural alterations similar to those described classically, and other undetermined minor structural alterations. Larynges presenting abnormalities were submitted to histological examination. Six cases of abnormalities were found in different larynges: one (1.79%) compatible with a sulcus vocalis and five (8.93%) compatible with a laryngeal micro-diaphragm. No cases of cysts or mucosal bridges were found. The observed abnormalities had characteristics similar to those described in other age groups. Abnormalities similar to sulcus vocalis or micro-diaphragm may be present at birth.

Burnout Syndrome In Nursing Assistants Of A Public Hospital In The State Of São Paulo.

The burnout syndrome is a psychosocial phenomenon that arises as a response to chronic interpersonal stressors present at work. There are many aspects that make nursing assistants vulnerable to chronic stress situations that may lead to burnout, highlighting the low degree of autonomy in the healthcare staff and spending more in direct contact with patients. To assess the prevalence of the burnout syndrome in nursing assistants in a public hospital, as well as its association with socio-demographic and professional variables. A socio-demographic and professional questionnaire and the Maslach Burnout Inventory (MBI-SS) were applied to 534 nursing assistants. The prevalence of burnout syndrome among nursing assistants was 5.9%. High emotional exhaustion was observed in 23.6%, 21.9% showed high depersonalization, and 29.9% low professional achievement. It was found statistically significant associations between emotional exhaustion, job sector and marital status; depersonalization, having children and health problems; low professional achievement and job sector and number of jobs. There was association between job satisfaction and the three dimensions. Professionals working in the health area must pay intense and extended attention to people who are dependent upon others. The intimate contact of the nursing assistants with hard-to-handle patients, as well as being afraid to make mistakes in healthcare are additional chronic stress factors and burnout syndrome cases related in this study.

O valor do diploma nas práticas de recrutamento de grandes empresas

Studies show that higher level diplomas make access to well-paid jobs easier and are an important source of prestige and social honor in Brazil. However, a broad literature today indicates a reduction of the importance of the diploma in hiring processes and argues that having a diploma becomes less and less sufficient for getting a job. This article examines the processes of selection of recently graduated engineers by eight large companies in the region of Campinas. Based on interviews with the main actors of the selection processes and on observation of the initial steps of a selection carried out by a consultancy company hired by one of the companies, the study shows that the weight of a diploma from a prestigious university is still the most important variable for the hiring decision, as it defines not only whether it will be possible to get the job or not, but also the access to vacancies that lead to better paid and more prestigious managerial positions. Finally, it discusses theoretical implications as well as what these results suggest in terms of public policies.

Acetatos homo e heterotrinucleares de ferro: um experimento para o laboratório de química de coordenação

Homo and heterotrinuclear acetates are unique compounds having μ3-oxo bridge and many interesting properties of such compounds are derived from this structure. Some undergraduate inorganic textbooks discuss several aspects of these compounds and we present here an undergraduate experiment for the high-yield synthesis of [Fe2MO(CH3CO2)6(H 2O)3], with M = Fe3+, Co2+ and Ni2+, as well as their characterization using infrared spectroscopy and cyclic voltametry. The proposed experiment gives the opportunity to discuss several concepts of coordination chemistry that follow the characterization techniques, such as: types of acetate coordination, reversibility of electrochemical processes, quelate and trans effects and lability.