The goal was to build a machine that could rapidly prototype PCBs using a moving light source and photoresist. The project failed, as the UV light did not make it through the lenses used to concentrate it. Better lenses and a laser would allow it to function better.

Orientador: Marcelo Moreira Ganzarolli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-22T20:18:14Z (GMT). No. of bitstreams: 1 Avelar_AnaCristina_M.pdf: 5757345 bytes, checksum: ab66436b252ec7b8b48d4756dd9e7f42 (MD5) Previous issue date: 1997 / Resumo: Os constantes avanços tecnológicos em eletrônica e informática tem tornado os sistemas eletrônicos cada vez mais compactos, aumentando-se a quantidade de calor a ser removida dos componentes e placas de circuito impresso. Por este motivo, atualmente são exigidos sistemas de dissipação de calor altamente eficientes. Este estudo analisa teórica e experimentalmente a transferência de calor em canais verticais formados por placas de circuito impresso dispostas paralelamente, resfriadas por convecção natural e propõe uma modelagem, baseada em relações existentes na literatura, que busca prever a distribuição de temperaturas em pontos significativos nos canais e placas em função da potência dissipada e da distância entre as placas. Este estudo visa também analisar os efeitos do aquecimento não-uniforme das placas que formam o canal. Na simulação teórica, devido à pequena espessura da placa o gradiente de temperatura ao longo da espessura da mesma foi desprezado e resolveu-se numericamente a equação de transferência de calor em coordenadas cartesianas bidimensionais e em regime permanente. Equacionou-se balanços de energia para os componentes e para o ar no canal e o problema foi resolvido numericamente através de um programa computacional. As placas de circuito impresso utilizadas nos testes experimentais, concebidas exclusivamente para fins de estudos térmicos, possuem uma base de epóxi com 25 resistores discretamente distribuídos sobre sua superfície de 200x164mm. Realizou-se testes com aquecimento uniforme e não-uniforme, variando-se a potência por componentes nas placas. Variou-se também as potências por placas e as distâncias entre as mesmas. Testou-se as potências de 2, 4,6 e 8 W e as distâncias entre placas de 12,24, e 48mm. Verificou-se boa concordância entre os resultados numéricos e experimentais, principalmente para a menor distância entre placas, 12 mm, onde a diferença entre os resultados teóricos e experimentais foi muito pequena / Abstract: The constant technological advances in electronics and computations have made the electronic system increasingly more compact, thus increasing the amount of heat to be removed ITomthe components and printed circuit boards. For this reason, highly efficient system of heat removal are presently required. This study analyses both theoretically and experimentallyheat transfer in an array of vertical parallel printed circuit boards, cooled off by natural convection and proposes a modeling, based on correlation found in literature which tries to predict temperature distribution in significant places in the channels and boards as regards dissipated power and distance among boards. This study also aims at analyzing nonuniform heating effets of the channel made boards. In the theoritical simulation, due to the board' s small thickness, the temperature gradient across the board has been neglected, and the equation of heat transfer in two-dimensional Cartesian was numericallysolved, and on a steady state. Energy balances for the componentes were formulated, and the problem was numerically solved by a computer programo The printed circuit boards used in the experimental tests, manufactured speciallyfor heat trasnfer studies have an epoxy basis with 25 resistors discretely distributed on 200 x 164 mm. Uniform and non-uniform heating tests were performed, thus a variation of power and distance among them had a variation. The 2, 4, 6 and 8 W power and distance among 12, 24 and 48 mm boards were tested. Good agreements between numerical and experimentalresults were observed, mainlyfor the smaller distance among boards, 12 mm, the differencesbetween the theoretical and experimentalresults were small / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

This thesis aims to prove the concept of replacing traditional electrical cabinets with PCBs on a fully electric boat. The existing solution with two electrical cabinets is considered expensive and believed to be replacable by PCBs.  Means of protections for PCBs are evaluated with regard to moisture, salt and vibrations. Two PCBs are designed to carry a current up to 60 ampere for a longer period of time. A cost analysis of 1, 10 and 100 PCBs are made to compare the cost of the proposed design to the existing solution. The result is a functioning prototype, a proposed design, cost analysis and suggested means of protections for withstanding the elements that the PCBs are exposed to at sea.Verification of the design is done by PDN Analysis and load testing with thermal imaging to monitor the temperature rise. Soley this is not enough to fully validate the design as further tests are needed and the local juristrictions has to be met before implementing these PCBs in consumer equipment.

The aim of the diploma thesis is to study the possibilities of creating a monitoring system for older production facilities already in operation. Select the necessary components for the nature of the equipment to create a system that is able to capture and provide information about activities on the equipment. The second goal is to design a suitable communication model for clear information about the operation, sending and storing data. The third goal is to analyze the dual-core ESP32 microprocessor against its predecessors in the role of system control unit.

This master thesis introduces the problematics of multilayer printed circuit boards. Theoretical part is focused on materials used for production of multilayer PCB and their parameters. At the same time, it focuses on the pressing process of multi-layered PCB, the types of presses used and their advantages and disadvantages. Practical part describes the methodology and testing of the PCB to identify the reliability of chosen electrical parameters. Testing is aimed to simulate thermal stress during machine soldering and during thermal stress in the target environment.

The main aim of this master’s thesis is to get acquainted with the theory of the current segmentation methods, that use deep learning. Segmentation neural network that will be capable of segmenting individual instances of the objects will be proposed and created based on theoretical knowledge. The main focus of the segmentation neural network will be segmentation of electronic components from printed circuit boards.

Printed Circuit Boards (PCBs) are a ubiquitous element of virtually every electronic system manufactured world-wide. It is not a stretch of the imagination to say that if it’s electronic, there is a PCB in it. PCBs are necessary tools for electronics work, and tools need to have instructions. For better or worse, PCB knowledge is a deep and wide ocean. There is much to cover for even a surface level understanding, and there are deep areas rich in technical expertise. Navigating the ocean of knowledge is treacherous; common knowledge of yore can be downright dubious now. PCB manufacturing and electronics as a whole have seen incredible developments in the past few decades, and knowledge once true may be outdated. At the same time there is a downpour of new techniques to use and challenges to face. The storm of information deepens the sea and can make it seem impossible to get anywhere without getting utterly lost. There are islands of knowledge out there hiding in books and papers and websites, but no guide to get anywhere. This thesis aims to guide the reader through the sea of information and provides a map that charts the shallows of beginner knowledge, into the deep depths of advanced design, of how and where to learn more. This thesis serves as an aiding means through the exciting and vast world of PCB design and layout.

[pt] O aumento do consumo de eletroeletrônicos e o desenvolvimento da tecnologia, proporcionou o surgimento de uma gama de produtos com diferentes funcionalidades, cada vez mais complexos e menores. As placas de circuito impresso (PCIs) são consideradas a parte principal dos dispositivos eletrônicos, sendo o cobre o seu componente elementar. O desenho e espessura das trilhas do circuito são determinantes para caracterizar a passagem de corrente elétrica nos equipamentos eletroeletrônicos e seu funcionamento está diretamente ligado a qualidade da confecção das trilhas do circuito. Este trabalho tem como objetivo estudar o processo de lixiviação do cobre, mediante a reação do ácido clorídrico, cloreto de cobre II e fluxo de ar. Além de investigar as condições experimentais ótimas do processo, que tem como principal característica a possibilidade de regeneração e reutilização da solução. Modelos para avaliar o efeito da concentração de ácido e fluxo de ar na corrosão das placas de circuito impresso foram desenvolvidos através da aplicação do planejamento experimental (pelo método clássico e por algoritmo genéticos em modelos polinomiais) e redes neurais artificiais. Visando encontrar as melhores condições experimentais para o sistema proposto, além de investigar a melhor técnica de predição do mesmo. Os resultados obtidos pelas previsões foram comparados com os resultados experimentais reais. As modelagens foram comparadas pela análise dos coeficientes de correlação (R2) e índices de erro (SSE, MSE e RMSE). Constatando-se que o modelo polinomial foi o mais adequado para prever a resposta. Através da investigação da superfície de resposta e curvas de contorno, foram identificadas as condições otimizadas para o processo. Das quais as concentrações ótimas de ácido clorídrico, cloreto de cobre II e fluxo de ar foram 1 mol.L-1, 0.3 mol.L-1 e 0.5 L/ min, respectivamente. / [en] The increased consumption of consumer electronics and the development of technology has led to the emergence of a range of products with different features, increasingly complex and smaller. Printed circuit boards (PCIs) are considered the main part of electronic devices, with copper being their elementary component. The design and thickness of the circuit tracks are crucial to characterize the passage of electric current in electronic equipment and its operation is directly linked to the quality of the circuit tracks. This work aims to study the copper leaching process through the reaction of hydrochloric acid, copper chloride II and airflow. In addition to investigating the optimal experimental conditions of the process, which has as its main feature the possibility of regeneration and reuse of the solution. Models to evaluate the effect of acid concentration and airflow on PCB corrosion were developed by applying experimental design (by the classical method and by the genetic algorithm in polynomial models) and artificial neural networks. Aiming to find the best experimental conditions for the proposed system, besides investigating the best prediction technique. The results obtained by the predictions were compared with the actual experimental results. The modeling was compared by analysis of correlation coefficients (R2) and error indices (SSE, MSE, and RMSE). Noting that the polynomial model was the most appropriate to predict the response. Through investigation of the response surface and contour curves, the optimized conditions for the process were identified. Of which the optimal concentrations of hydrochloric acid, copper chloride II and airflow were 1 mol.L-1, 0.3 mol.L-1 and 0.5 L / min, respectively.

Rising fuel costs and concerns about air pollution have significantly increased interest in electric vehicles (EVs). EVs are equipped with rechargeable batteries that can be fully recharged by connecting to an external electrical source. However, the wider adoption of EVs is hindered by the need for an on-board charger system that is both lightweight and efficient. EVs utilize two main charging methods: on-board chargers (OBC) for regular charging and off-board (fast) chargers for quick refills of battery pack. Most EVs currently use 400V battery packs paired with 6.6kW or 11kW OBCs, while larger vehicles with over 100 kWh battery packs employ 16.5kW or 19.2kW OBCs, constrained by household voltage and current limits. Some manufacturers are transitioning to 800V battery packs to lower costs and enhance fast charging capabilities, necessitating the development of 800V OBCs with high efficiency and power density. For household use, EVs can charge via OBC in a grid-to-vehicle transfer and can supply energy back to the home or grid (vehicle-to-grid) for emergency use or to support smart grid functionalities, requiring bidirectional OBCs. Advanced power semiconductor devices have been instrumental in advancing power conversion technology. The introduction of power semiconductor devices based on wide bandgap (WBG) materials marks a revolutionary shift, offering potential improvements over silicon-based devices. These WBG devices are capable of achieving higher efficiency, and higher power density in power conversion at higher operation frequency. Elevating the switching frequency diminishes the voltage-second across the transformer, facilitating the utilization of printed-circuit-board (PCB) technology for the windings as opposed to Litz wire implementations. Compared to traditional Litz wire-based transformers, the manufacturing process is significantly streamlined, and the management of parasitic is considerably more straightforward. Furthermore, the integration of resonant inductors with PCB-based transformer results in a reduction in the overall number of magnetic components and improved power density. This dissertation focuses on the DC/DC conversion stage of a bi-directional battery charger. It aims to achieve high power density and high efficiency using a PCB-based integrated transformer, enhancing manufacturing processes. The dissertation details the specific accomplishments in this area: Firstly, a two-stage on-board charger structure for 800 V battery EVs is proposed. The first stage is a four-phase bridgeless totem pole AC/DC converter working at critical conduction mode (CRM) so that soft switching can be achieved for all the fast switches. The second stage is single phase CLLC (1PCLLC) converter which is attractive due to its less component counts of devices and driver circuits. A novel matrix integrated transformer with controllable built-in leakage inductance for bi-directional 1PCLLC converter was proposed. Integrating three UI-core-based (1UI-based) elemental transformers with non-perfectly interleaved winding structures into one 3UI-based integrated transformer can reduce the core loss significantly with a smaller footprint compared with three EI-core-based integrated transformers. The proposed integrated magnetics can be scalable for higher voltage and higher power converters by assembling more 1UI-based elemental transformers. A SiC-based 1PCLLC converter prototype operating at 250-kHz switching frequency for 11-kW OBC applications was built with the proposed integrated transformer, and it can achieve a power density of 250 W/in3 with maximum efficiency of 98.4%. Secondly, the challenge of increased common mode (CM) noise after adopting PCB-based windings in the design was discussed. The inter-winding capacitors between the primary and secondary windings act as a conduction path for high dv/dt CM noise, which can lead to electromagnetic interference (EMI) issues. To address this, a winding cancellation method for an integrated matrix transformer in a 1PCLLC converter was proposed and validated. This approach was tested in an 11-kW 1PCLLC converter. The EMI measurement results align with the analysis, confirming the effectiveness of the proposed method, which achieved a reduction in CM noise by 17dB. Furthermore, the 1PCLLC converter, incorporating the proposed planar matrix integrated transformer and winding cancellation technique, attained a power density of 420 W/in³ and a peak efficiency of 98.5%. Thirdly, to enhance efficiency further, the 1PCLLC converter is substituted with the proposed three-phase CLLC (3PCLLC) resonant converter equipped with three-phase rectifiers. The 3PCLLC converter becomes more promising for high power applications as its lower RMS current stress and automatic current sharing capabilities. It can achieve soft switching under all conditions. In addition, due to the symmetrical resonant tank, it is more suitable for bi-directional operation. Variable DC-link voltage is adopted so that the DC/DC stage can always work at its optimized point, providing best efficiency for the entire battery voltage. An improved core structure for the three-phase integrated transformer was proposed to reduce the core loss and simplify the magnetic components by integrating three primary resonant inductors, three secondary resonant inductors and three transformers into one magnetic component. A systematic method of converter design which includes the design of integrated transformer, converter loss optimization was adopted to design an 11kW 3PCLLC resonant converter. A SiC-based 3PCLLC converter prototype operating at 250-kHz switching frequency for 11-kW OBC applications was built with the proposed integrated transformer, and it can achieve a power density of 330 W/in3 with peak efficiency of 98.7%. Fourthly, the power level of OBC continues to increase to make up the large capacitance battery pack inside the EVs to relief the concern of mileage range. To address this challenge of higher power, a scalable matrix integrated transformer for multi-phase CLLC converter was proposed. A universal method of integrating magnetizing inductance with built-in leakage inductance based on multiple perfectly coupled transformers (PCTs). The integration of built-in leakage inductance can be achieved by connecting several PCTs using a standardized core type for cost considerations or can be further integrated into a customized core with interleaved magnetomotive force polarities across transformer legs to achieve better flux distribution and smaller core loss. The proposed concept can be applied to single-input single-output, and multiple-inputs multiple-outputs integrated transformer applications. A 3x3 PCTs-based integrated transformer built with PCB windings was designed for a 3PCLLC resonant converter, which integrates three primary resonant inductors, three secondary resonant inductors, and three transformers into one magnetic core to simplify the complexity of the converter. The effectiveness of the proposed concept was demonstrated through a high-efficiency, high-power density 3PCLLC DC/DC converter for an 800V 16.5kW OBC. The designed converter can achieve a power density of 500 W/in3 and a peak efficiency of 98.8%. / Doctor of Philosophy / Rising fuel costs and concerns about air pollution have significantly increased interest in electric vehicles (EVs). EVs are equipped with rechargeable batteries that can be fully recharged by connecting to an external electrical source. However, the wider adoption of EVs is hindered by the need for an on-board charger system that is both lightweight and efficient. The dissertation presents advances in OBC technology to address these challenges, focusing on the development of efficient, high-power density OBCs suitable for various EV applications. EVs utilize two main charging methods: on-board chargers (OBC) for regular charging and off-board (fast) chargers for quick refills of battery pack. Most EVs currently use 400V battery packs paired with 6.6kW or 11kW OBCs, while larger vehicles with over 100 kWh battery packs employ 16.5kW or 19.2kW OBCs, constrained by household voltage and current limits. Some manufacturers are transitioning to 800V battery packs to lower costs and enhance fast charging capabilities, necessitating the development of 800V OBCs with high efficiency and power density. For household use, EVs can charge via OBC in a grid-to-vehicle transfer and can supply energy back to the home or grid (vehicle-to-grid) for emergency use or to support smart grid functionalities, requiring bidirectional OBCs. Advanced power semiconductor devices have been instrumental in advancing power conversion technology. The introduction of power semiconductor devices based on wide bandgap (WBG) materials marks a revolutionary shift, offering potential improvements over silicon-based devices. These WBG devices are capable of achieving higher efficiency, and higher power density in power conversion at higher operation frequency. Elevating the switching frequency diminishes the voltage-second across the transformer, facilitating the utilization of printed circuit board (PCB) technology for the windings as opposed to Litz wire implementations. Compared to traditional Litz wire-based transformers, the manufacturing process is significantly streamlined, and the management of parasitic is considerably more straightforward. Furthermore, the integration of resonant inductors with PCB-based transformer results in a reduction in the overall number of magnetic components and improved power density. Addressing cost concerns, a novel, cost-effective single-phase converter design was proposed, achieving high efficiency with integrated magnetics. Additionally, the research tackled the challenge of electromagnetic interference (EMI) through a winding cancellation technique, significantly reducing common-mode noise and further improving the converter's performance. The research introduces an improved core structure for a three-phase integrated transformer, significantly reducing core loss and simplifying the design by combining multiple components into a single unit. This approach facilitated the creation of a high-efficiency, SiC-based converter prototype, demonstrating remarkable power density and peak efficiency compared with state-of-the-art solutions. To accommodate the increasing power requirements of OBCs, a scalable, matrix integrated transformer design was developed for multi-phase converters, optimizing cost and performance. This design simplifies the converter architecture, enhancing efficiency and power density, and is adaptable to both single and multiple output applications. These advancements offer promising solutions to the challenges hindering the wider adoption of EVs. The dissertation underscores the potential of advanced power conversion technologies, including the application of WBG devices, integrated magnetics to streamline converter design and enhance both the efficiency and power density of battery chargers.

The FDR (Frequency Disturbance Recorder) is a data acquisition device for the power system. The device is portable and can be used with any residential wall outlet for frequency data collection. Furthermore, the FDR transmits calculated frequency data to the web for access by authorized users via Ethernet connection. As a result, Virginia Tech implemented Frequency Monitoring Network (FNET) with these FDR devices. FNET is a collection of identical FDRs placed in different measurement sites to allow for data integration and comparison. Frequency is an important factor for power system control and stabilization. With funding and support provided by ABB, TVA and NSF the FDRs are placed strategically all over the United States for frequency analysis, power system protection and monitoring. The purpose of this study is to refine the current FDR hardware design and establish a new design that will physically fit all the components on one Printed Circuit Board (PCB). At the same time, the software that is to be implemented on the new board is to be kept similar if not the same as that of the current design. The current FDR uses the Axiom CME555 development board and it is interfaced to the external devices through its communication ports. Even through the CME555 board is able to meet the demands of the basic FDR operations, there are still several problems associated with this design. This paper will address some of those hardware problems, as well as propose a new board design that is specifically aimed for operations of FDR. / Master of Science