Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / This dissertation presents the combination of an electrical and thermal model to represent the characteristics of the photovoltaic module floating in water. Based on the proposed model a MATLAB / Simulink software simulation is made and validated with data obtained through a experiment performed. Two experiments were conducted in the UFC Alternative Energy Laboratory in order to validate the model proposed by the use of two distinct manufacturing photovoltaic modules, a monocrystalline produced by Azur Solar GmbH model TSM 160M and a polycrystalline produced by Solartec model KS20T. The model proposed was satisfactory compared the model results with measured data, which is irradiance, temperature front, rear and IV characteristic curve of the PV module. The irradiance is obtained by a pyranometer LP02 model Hukseflux manufactured by Thermal Sensor, temperatures were measured with temperature sensors type thermo EN 100 and the characteristic curves were obtained by tracer curve mini-KLA, manufactured by IngenieurbÃro. The monocrystalline module errors were lower than 4% for short-circuit current values, open circuit voltage and maximum power point. To reduce the error the electric model initially proposed was changed at the point of maximum power and were obtained errors lower than 2% for the short-circuit current values, open circuit voltage and maximum power point. The polycrystalline module showed errors lower than 10% for the short-circuit current values, open circuit voltage and maximum power point. The polycrystalline module floating in water performance was compared to the conventional use (installed on the ground), being recorded a cell temperature difference at any given time of day to 29 ÂC between the two applications; as a consequence, better efficiency was obtained floating on the water module with power gains of up to 17% compared to conventional usage. / Esta dissertaÃÃo apresenta a combinaÃÃo de um modelo elÃtrico e tÃrmico para representar as caracterÃsticas do mÃdulo fotovoltaico flutuante em Ãgua. A partir do modelo proposto à realizada simulaÃÃo no software MATLAB/Simulink e validado com dados obtidos atravÃs de experimento realizado. Foram realizados dois experimentos no LaboratÃrio de Energias Alternativas da UFC a fim de validar o modelo proposto atravÃs da utilizaÃÃo de dois mÃdulos fotovoltaicos de caracterÃstica de fabricaÃÃo distintas, um monocristalino da Azur Solar GmbH modelo TSM 160M e um policristalino da Solartec modelo KS20T. O modelo proposto mostrou-se satisfatÃrio quando comparado os resultados do modelo com os dados medidos, que sÃo irradiÃncia, temperatura frontal, posterior e curva caracterÃstica I-V do mÃdulo fotovoltaico. A irradiÃncia à obtida atravÃs do piranÃmetro modelo LP02 do fabricante Hukseflux Thermal Sensor, as temperaturas foram medidas com sensores de temperatura tipo termorresistÃncia PT 100 e a curvas caracterÃsticas foram obtidas atravÃs do traÃador de cuva mini-KLA, do fabricante IngenieurbÃro. O mÃdulo monocristalino apresentou erros inferiores a 4% para os valores de corrente de curto-circuito, tensÃo de circuito aberto e ponto de mÃxima potÃncia. Visando diminuir o erro alterou-se o modelo elÃtrico proposto inicialmente no ponto de mÃxima potÃncia e foram obtidos erros inferiores a 2% para os valores de corrente de curto-circuito, tensÃo de circuito aberto e ponto de mÃxima potÃncia. O mÃdulo policristalino apresentou erros inferiores a 10% para os valores de corrente de curto-circuito, tensÃo de circuito aberto e ponto de mÃxima potÃncia. Observou-se o rendimento do mÃdulo policristalino flutuante em Ãgua em relaÃÃo ao uso convencional (instalado sobre o solo), sendo registrada uma diferenÃa de temperatura da cÃlula em determinado horÃrio do dia de atà 29ÂC entre as duas aplicaÃÃes; como consequÃncia, obteve-se melhor eficiÃncia do mÃdulo flutuante em Ãgua com ganhos de potÃncia de atà 17% em relaÃÃo ao uso convencional.

Ce mémoire est centré sur l’application de la technique d’optimisation de type Space Mapping dans le cadre du dimensionnement d’actionneurs électriques pris en compte par des modélisations multi-physiques. L’intérêt particulièrement recherché de ce type de méthode est la réduction potentiellement forte du coût du dimensionnement optimal. Cette volonté de réduction du coût de l’approche optimale s’explique par plusieurs considérations. En premier lieu, la modélisation des actionneurs tend à considérer de plus en plus de phénomènes physiques (tels que les phénomènes magnétiques, électriques, thermiques, mécaniques …) afin de décrire au mieux les phénomènes observés et mesurés. En second lieu il devient alors nécessaire de tenir compte des couplages entre ces physiques afin de traduire au plus juste l’interdépendance de ces phénomènes. Dans ce cadre, un travail particulier a été réalisé concernant la prise en compte des aspects thermiques dans les machines électriques. C’est ainsi qu’un modèle thermique à constantes localisées d’une machine synchrone à aimants permanents a été construit. Pour valider les résultats de calcul et préciser la définition de certain de ses éléments, une démarche expérimentale a été réalisée. Tous ces points, traduits dans le plan numérique, haussent le coût de l’évaluation des performances des actionneurs, et donc celui de leurs dimensionnements. De là, l’utilisation des techniques d’optimisation basées sur des modèles substituts permet d’envisager des réductions significatives des coûts de dimensionnement. La technique de Space Mapping est utilisée dans ce travail comme solution pour trouver un compromis entre la qualité des solutions trouvées et le temps de calcul. Plus particulièrement, elle est utilisée pour résoudre un problème de dimensionnement optimal d’une machine synchrone à aimants permanents assurant la fonction de démarreur dans une application de véhicule hybride. L’approche d’optimisation par Space Mapping a été comparée à celle, plus classique, n’utilisant qu’une seule modélisation de l’actionneur à dimensionner, c’est-à-dire sans modèle substitut. Il est montré que les techniques de Space Mapping sont à même de trouver des solutions de dimensionnement similaires à celles issues d’une approche classique, mais de manière beaucoup plus efficace, i.e. en utilisant un nombre plus faible d’évaluations de la modélisation multi-physique de l’actionneur. / This thesis focuses on the application of the Space Mapping optimization technique in the case of the sizing of electrical actuators taking into account a multi-physical modeling. The main interest in this type of optimization method is to considerably reduce the cost of optimal sizing. The need to use such optimization approach is due to several considerations. First, electrical actuators modeling tends to increasingly require the consideration of several physical phenomena (such as magnetic, electrical thermal and mechanical phenomena) in order to better describe observed and measured phenomena. Besides, it becomes necessary to take into account couplings between the different physical phenomena to precisely calculate the interdependencies between these phenomena. In this context, taking into account the thermal aspect in the case of electrical machines is particularly highlighted. A lumped parameter model of a permanent magnet synchronous machine is built. An experimental procedure has been followed to validate calculation results and define some elements of the proposed model. When implemented numerically, all points mentioned above increase the cost of the calculation of the performances of the electrical actuator, and then the cost of the optimal sizing. Thus, the use of an optimization technique based on surrogate models permits to reduce the optimal sizing cost. Space Mapping technique was used in this work as a solution to find a compromise between the quality of the found results and the calculation time. It is particularly used to solve an optimal sizing problem of a permanent magnet synchronous machine used as starter in a hybrid vehicle application. The Space Mapping optimization approach was compared to a classical one using a unique modeling of sized the electrical actuator : no surrogate model is used in the classical approach. Il is demonstrated that the Space Mapping techniques find optimization results that are similar to those found by the classical approach, yet, in a much more efficiently. Space Mapping techniques require only few calculations of the multi-physical model of the actuator.

No description available.

This thesis consists of three main objectives: fundamental and literature review of EV batteries, experimental development, and validation of two liquid cooling battery modules, thermal modeling and comparison of the inter-cell cooling battery module. / The traditional vehicles with internal combustion engine have resulted in severe environmental pollution, which motivates the development of electric vehicles and hybrid electric vehicles. Due to a low energy density and long refueling time of the battery pack, it is still hard for electric vehicles and hybrid electric vehicles to be widely accepted by the consumers. As the batteries with a better ultra-fast charging capability are massively produced, the range anxiety issue is somewhat alleviated. During a charging with large current magnitude, the battery generally has a great amount of heat generation and evident temperature rise. Therefore, a thermal management system is necessary to effectively dissipate the battery loss and minimize the degradation mechanisms caused by extreme temperature. The motivation of this thesis is to study the discipline of the battery thermal management system as an application for electric vehicles. The design methodologies are presented in both experiment test and numerical simulation. For the comparative study between active liquid cooling methods for a lithium-ion battery module using experimental techniques, two battery modules with three Kokam Nickel Manganese Cobalt battery cells connected in parallel are developed. One has liquid coolant flowing along the edge of the model, and another with liquid coolant flowing between the cells. Several characterization tests, including thermal resistance tests, fast charging tests up to 5C, and drive cycle tests are designed and performed on the battery module. The inter-cell cooling module has a lower peak temperature rise and faster thermal response compared to the edge cooling module, i.e., 4.1⁰C peak temperature rise under 5C charging for inter-cell cooling method and 14.2⁰C for edge cooling method. The thermal models built in ANSYS represent the numerical simulation of the inter-cell cooling module as a comparison with the experiment. A cell loss model is developed to calculate the battery heat generation rate under ultra-fast charging tests and a road trip test, which are further adopted as the inputs to the thermal models. The simulation of the 5C ultra-fast charging test gives the peak temperature rise just 0.47⁰C lower than the experimental measurement, it indicates that the FEA thermal models can provide an accurate temperature prediction of the battery module. / Thesis / Master of Applied Science (MASc) / With a demanding market of electric vehicles, battery technologies have grown rapidly in recent years. Among all the battery research topics, the development of ultra-fast charging, that can fully charge the battery pack within 15 minutes, is the most promising direction to address the range anxiety and improve the social acceptance of electric vehicles. Nevertheless, the application of ultra-fast charging has many challenges. In particular, an efficient thermal management system is significant to guarantee the safety and prolong the service life of the battery pack. This thesis contributes to study the fundamentals of the battery field, and design liquid cooling systems to observe the thermal behavior of a battery prototype module under fast charging and general use. FEA thermal modeling of the battery module is developed to provide a guide for further test validation.

In order to support UCLA’s development of the 3 cm Miniature Xenon Ion (MiXI) thruster, Cal Poly has a 3 cm thruster under development. This version, called MiXI Cal Poly Version 1 (MiXI-CPv1), is complete and has been utilized in vacuum chamber thermal validation testing. Testing on this version was used to check the validity of heat transfer simulations modeled in SolidWorks. Investigations of the 3 cm ion thruster configuration were intended to discover the driving factors affecting the thermal behavior of the discharge chamber and surrounding design space. Numerical simulations indicate that the heating of the samarium cobalt permanent magnets can be mitigated through the implementation of two proposed modifications. The first modification is to implement a 2% thoriated tungsten filament cathode. This design exhibited maximum permanent magnet temperatures of 325°C, twenty-five degrees below the maximum upper temperature of 350°C. Since some magnetic degaussing effects have been observed at temperatures above 300°C, the aforementioned solution can be combined with a thruster design modification to achieve a reduced permanent magnet temperature of 298°C. This modification would involve increase the anode wall thickness from approximately 0.7 mm to 2 mm below the permanent magnet ring, creating a stepped anode design. Additionally, less effective solutions were proposed and modeled and are presented for completeness.

No description available.

With the increase dependency on electricity to provide correct form of electricity for lightning, machines, and home and office appliances, the need for the introduction of high reliability power electronics in converting the raw form of electricity into efficient electricity for these applications is uprising. One of the most common failures in power electronics is temperature related failure such as overheating. To address the issue of overheating, thermal management becomes an important mission in the design of the power electronics to ensure the functional power electronics. Different approaches are taken by academia and industry researchers to provide efficient power electronics. In particular, the Center for Power Electronics System (CPES) at Virginia Tech and four other universities presented the IPEM approach by introducing integrated power electronics modules (IPEM) as standardized units that will enable greater integration within power electronics systems and their end-use application. The IPEM approach increases the integration in the components that make up a power electronics system through novel a packaging technique known as Embedded Power technology. While the thermal behavior of commonly used packages such as pin grid arrays (PGA), ball grid array (BGA), or quad flat pack (QFP) are well-studied, the influence of the Embedded Power packaging architecture on the overall thermal performance of the IPEMs is not well known. This motivates the presentation of this dissertation in developing an in-depth understanding on the thermal behavior of the Embedded Power modules. In addition, this dissertation outlines some general guidelines for the thermal modeling and thermal testing for the Embedded Power modules. Finally, this dissertation summarizes a few thermal design guidelines for the Embedded Power modules. Hence, this dissertation aims to present significant and generalized scientific findings for the Embedded Power packaging from the thermal perspective. Both numerical and experimental approaches were used in the studies. Three-dimensional mathematical modeling and computational fluid dynamics (CFD) thermal analyses were performed using commercial numerical software, I-DEAS. Experiments were conducted to validate the numerical models, characterize the thermal performance of the Embedded Power modules, and investigate various cooling strategies for the Embedded Power modules. Validated thermal models were used for various thermal analyses including identifying potential thermal problems, recognizing critical thermal design parameters, and exploring different integrated cooling strategies. This research quantifies various thermal design parameters such as the geometrical effect and the material properties on the thermal performance of the Embedded Power modules. These parameters include the chip-to-chip distance, the copper trace area, the polyimide thickness, and the ceramic materials. Since the Embedded Power technology utilizes metallization bonding as interconnection, specific design parameters such as the interconnect via holes pattern and size, the metallization thickness, as well as the metallization materials were also explored to achieve best results based on thermal and stress analyses. With identified potential thermal problems and critical thermal design parameters, different integrated cooling strategies were studied. The concept of integrated cooling is to incorporate the cooling mechanisms into the structure of Embedded Power modules. The results showed that simple structural modifications to the current Embedded Power modules can reduce the maximum temperature of the module by as much as 24%. Further improvement can be achieved by employing double-sided cooling to the Embedded Power modules. Based on the findings from the thermal analyses, general design guidelines were developed for future design of such Embedded Power modules. In addition, thermal modeling and testing guidelines for the Embedded Power modules were also outlined in this dissertation. / Ph. D.

Continental rifting ultimately creates a deep accommodation space for sediment. When a major river flows into a late-stage rift, thick deltaic sediment can change the thermal regime and alter the mechanisms of extension and continental breakup. The Salton Trough, the northernmost rift segment of the Gulf of California plate boundary, has experienced the same extension as the rest of the Gulf, but is filled to sea level by sediment from the Colorado River. Unlike the southern Gulf, seafloor spreading has not initiated. Instead, seismicity, high heat flow, and minor volcanoes attest to ongoing rifting of thin, transitional crust. Recently acquired controlled-source seismic refraction and wide-angle reflection data in the Salton Trough provide constraints upon crustal architecture and active rift processes. The crust in the central Salton Trough is only 17-18 km thick, with a strongly layered but relatively one-dimensional structure for ~100 km in the direction of plate motion. The upper crust includes 2-3 km of Colorado River sediment. The basement below the sediment is interpreted to be similar sediment metamorphosed by the high heat flow and geothermal activity. Meta-sedimentary rock extends to at least 7-8 km depth. A 4-5 km thick layer in the middle crust is either additional meta-sedimentary rock or stretched pre-existing continental crust. The lowermost 4-5 km of the crust is rift-related mafic magmatic material underplated from partial melting in the hot upper mantle. North American lithosphere in the Salton Trough has been almost or completely rifted apart. The gap has been filled by ~100 km of new transitional crust created by magmatism from below and sedimentation from above. These processes create strong lithologic, thermal, and rheologic layering. Brittle extension occurs within new meta-sedimentary rock. The lower crust, in comparison, stretches by ductile flow and magmatism is not localized. This seismic interpretation is also supported by 1D thermal and rheological modeling. In this passive rift driven by far-field extensional stresses, rapid sedimentation keeps the crust thick and ductile, which delays final breakup of the crust and the initiation of seafloor spreading. / Ph. D.

Lithium-ion batteries are critical components in electric vehicles, portable electronics, and grid energy storage systems, necessitating advanced modeling techniques to enhance their safety, performance, and lifespan. This thesis presents the development and validation of a coupled electrical and lumped thermal model for cylindrical lithium-ion batteries along with a finite difference thermal model for spatial temperature prediction of cylindrical cell These models address key challenges in simulating real-world battery behavior. The electrical model utilizes a 2 R-C pair equivalent circuit framework integrated with a busbar model to account for current imbalances in parallel-connected cells. This model is a common equivalent circuit model used to represent a Li-ion cell using a voltage source, series resistor, and two resistor-capacitor pair connected in parallel. A lumped thermal model coupled with the electrical framework dynamically adjusts parameters based on temperature variations, achieving a voltage prediction error of less than 200 mV. Additionally, the thermal model employs a finite difference method (FDM) to solve the 3D transient heat conduction equation, providing spatial temperature distribution within cells and capturing critical gradients between core and surface temperatures. The vectorization of the thermal solver reduced simulation time by half, and its validation against Ansys™ simulations and module-level data demonstrated temperature prediction accuracy within a 2–3°C margin. The developed tool is scalable for any number of cylindrical cells arranged in a rectangular grid, addressing key gaps identified in the literature, including the need to simulate spatial and temporal non-uniformities in state-of-charge (SOC), state-of-health (SOH), and temperature, which significantly affect battery performance and lifespan. It provides a scalable, efficient tool for predicting thermal and electrical behavior across cell and module levels. This work contributes to the development of a tool that will, enable informed design decisions for next-generation energy storage systems. Future research could focus on extending the model to incorporate aging effects, enhanced thermal management configurations, and real-time simulations for battery management systems. / Master of Science / Lithium-ion batteries play a crucial role in powering electric vehicles, smartphones, and renewable energy storage systems. As demand for these technologies grows, ensuring that batteries operate safely and efficiently becomes increasingly important. This research focuses on developing computer models that simulate how lithium-ion batteries behave under different conditions, helping engineers design better and longer-lasting batteries. The project introduces two main models: an electrical model that predicts how energy flows through a battery and a thermal model that estimates how the battery heats up during use. The electrical model simplifies complex battery behavior by representing it with basic circuit components, while the thermal model uses advanced calculations to simulate how heat spreads within the battery. By combining these models, the research creates a tool that can predict how batteries perform over time and how temperature changes affect their efficiency and lifespan. One of the key achievements of this work is improving the speed and accuracy of these simulations. The thermal model was enhanced to calculate heat distribution more efficiently, cutting simulation times in half. The model was also validated against industry-standard tools like Ansys™, with results showing temperature predictions within a 2-3°C margin of error. This tool can simulate battery packs of any size, making it valuable for designing electric vehicle batteries and large-scale energy storage systems. By identifying potential issues like overheating or uneven energy distribution, the model helps engineers develop safer and more reliable battery technologies. Ultimately, this research contributes to the advancement of energy storage systems, supporting the transition to cleaner and more sustainable energy solutions for the future.

Major challenges in maintaining quality and reliability in today’s microelectronics devices come from the ever increasing level of integration in the device fabrication, as well as the high level of current densities that are carried through the microchip during operation. In order to have a framework for design and reliability assessment, it is imperative to develop a predictive capability for the thermal response of micro-electronic components. A computationally efficient and accurate multi-scale transient thermal methodology was developed using a combination of two different approaches: “Progressive Zoom-in” method and “Proper Orthogonal Decomposition (POD)” technique. The proposed technique has the capability of handling several decades of length scale from tens of millimeter at “package” level to several nanometers at “interconnects” level at a considerably lower computational cost, while maintaining satisfactory accuracy. This ability also applies for time scales from seconds to microseconds corresponding to various transient thermal events. The proposed method also provides the ability to rapidly predict thermal responses under different power input patterns, based on only a few representative detailed simulations, without compromising the desired spatial and temporal resolutions. It is demonstrated that utilizing the proposed model, the computational time is reduced by at least two orders of magnitude at every step of modeling. Additionally, a novel experimental platform was developed to evaluate rapid transient Joule heating in embedded nanoscale metallic films representing buried on-chip interconnects that are not directly accessible. Utilizing the state-of-the-art sub-micron embedded resistance thermometry the effect of rapid transient power input profiles with different amplitudes and frequencies were studied. It is also demonstrated that a spatial resolution of 6 µm and thermal time constant of below 1 µs can be achieved using this technique. Ultimately, the size effects on the thermal and material properties of embedded metallic films were studied. A state-of-the-art technique to extract thermal conductivity of embedded nanoscale interconnects was developed. The proposed structure is the first device that has enabled the conductivity measurement of embedded metallic films on a substrate. It accounts for the effect of the substrate and interface without compromising the sensitivity of the device to the thermal conductivity of the metallic film. Another advantage of the proposed technique is that it can be integrated within the structure and be used for measurements of embedded or buried structures such as nanoscale on chip interconnects, without requiring extensive micro-fabrication. The dependence of the thermal conductivity on temperature was also investigated. The experimentally measured values for thermal conductivity and its dependence on temperature agree well with previous studies on free-standing nanoscale metallic bridges.