Homogeneous Charge Compression Ignition (HCCI) Engines hold promises of being the next generation of internal combustion engines due to their ability to produce high thermal efficiencies and low emission levels. HCCI combustion is achieved through the auto-ignition of a compressed homogenous fuel-air mixture, thus making it a "fusion" between spark-ignition and compression-ignition engines. The main challenge in developing HCCI engines is the absence of a combustion trigger hence making it difficult to control its combustion timing. The aim of this research project is to model and control a natural gas HCCI engine. Since HCCI depends primarily on temperature and chemical composition of the mixture, Exhaust Gas Recirculation (EGR) is used to control ignition timing. In this research, a thermodynamical, physics-based nonlinear model is developed to capture the main features of the HCCI engine. In addition, the Modified Knock Integral Model (MKIM), used to predict ignition timing, is optimized. To validate the nonlinear model, ignition timing under varying conditions using the MKIM approach is shown to be in accordance with data acquired from a model developed using a sophisticated engine simulation program, GT-Power. Most control strategies are based on a linear model, therefore, the nonlinear model is linearized using the perturbation method. The linear model is validated by comparing its performance with the nonlinear model about a suitable operating point. The control of ignition timing can be defined as a regulation process where the goal is to force the nonlinear model to track a desired ignition timing by controlling the EGR ratio. Parameters from the linear model are used to determine the gains of the LQR controller. The performance of the controller is validated by implementing it on the nonlinear model and observing its ability to track the desired timing with 0.5% error within a certain operating range. To increase the operating range of the controller and reduce steady-state error, an integrator is added to the LQR. Finally, it is shown that the LQR controller is able to successfully reject disturbance, parameter variation, as well as noise.

The low-frequency electromagnetic compatibility (EMC) is an increasingly important aspect in the design of practical systems to ensure the functional safety and reliability of complex products. The opportunities for using numerical techniques to predict and analyze system’s EMC are therefore of considerable interest in many industries. As the first phase of study, a proper model, including all the details of the component, was required. Therefore, the advances in EMC modeling were studied with classifying analytical and numerical models. The selected model was finite element (FE) modeling, coupled with the distributed network method, to generate the model of the converter’s components and obtain the frequency behavioral model of the converter. The method has the ability to reveal the behavior of parasitic elements and higher resonances, which have critical impacts in studying EMI problems. For the EMC and signature studies of the machine drives, the equivalent source modeling was studied. Considering the details of the multi-machine environment, including actual models, some innovation in equivalent source modeling was performed to decrease the simulation time dramatically. Several models were designed in this study and the voltage current cube model and wire model have the best result. The GA-based PSO method is used as the optimization process. Superposition and suppression of the fields in coupling the components were also studied and verified. The simulation time of the equivalent model is 80-100 times lower than the detailed model. All tests were verified experimentally. As the application of EMC and signature study, the fault diagnosis and condition monitoring of an induction motor drive was developed using radiated fields. In addition to experimental tests, the 3DFE analysis was coupled with circuit-based software to implement the incipient fault cases. The identification was implemented using ANN for seventy various faulty cases. The simulation results were verified experimentally. Finally, the identification of the types of power components were implemented. The results show that it is possible to identify the type of components, as well as the faulty components, by comparing the amplitudes of their stray field harmonics. The identification using the stray fields is nondestructive and can be used for the setups that cannot go offline and be dismantled

We propose a new atmospheric model based on first-principles for the simulation of clouds. Our approach is able to simulate the realistic formation of various cloud types, such as cumulus, stratus, stratocumulus, their temporal evolution, and transitions between cloud types. Moreover, we are able to model strongly rotating thunderstorms known as supercells. Our method allows us to simulate cloud formations of up to about 20 km 20 km at interactive rates. For the intuitive exploration, we identified a light-weight parameter set to interactively explore cloud formations. We demonstrate that our model can be coupled with data from real-time weather services to simulate cloud formations in the now. Moreover, we present a novel approach for the simulation of wildfires. Our model is able to realistically capture the combustion process of trees, heat transfer with the environment and fire propagation between trees. We demonstrate that our approach is capable of realistically simulating the propagation of fire through entire ecosystems with varying vegetation occupancy. We integrated our atmospheric model which allows us to simulated clouds emerging from the evaporation of water from burning trees leading to complex so called flammagenitus patterns which are usually observed over wildfires. Our system runs at interactive rates which enables the exploration of wildfires in different environments.

The main objective for physics based modeling of the power converter components is to design the whole converter with respect to physical and operational constraints. Therefore, all the elements and components of the energy conversion system are modeled numerically and combined together to achieve the whole system behavioral model. Previously proposed high frequency (HF) models of power converters are based on circuit models that are only related to the parasitic inner parameters of the power devices and the connections between the components. This dissertation aims to obtain appropriate physics-based models for power conversion systems, which not only can represent the steady state behavior of the components, but also can predict their high frequency characteristics. The developed physics-based model would represent the physical device with a high level of accuracy in predicting its operating condition. The proposed physics-based model enables us to accurately develop components such as; effective EMI filters, switching algorithms and circuit topologies [7]. One of the applications of the developed modeling technique is design of new sets of topologies for high-frequency, high efficiency converters for variable speed drives. The main advantage of the modeling method, presented in this dissertation, is the practical design of an inverter for high power applications with the ability to overcome the blocking voltage limitations of available power semiconductor devices. Another advantage is selection of the best matching topology with inherent reduction of switching losses which can be utilized to improve the overall efficiency. The physics-based modeling approach, in this dissertation, makes it possible to design any power electronic conversion system to meet electromagnetic standards and design constraints. This includes physical characteristics such as; decreasing the size and weight of the package, optimized interactions with the neighboring components and higher power density. In addition, the electromagnetic behaviors and signatures can be evaluated including the study of conducted and radiated EMI interactions in addition to the design of attenuation measures and enclosures.

The mm-wave frequency range is being increasingly researched to close the gap between 100 to 1000 GHz, the least explored region of the electromagnetic spectrum, often termed as the 'THz Gap'. The ever increasing demand for compact, portable and reliable THz (Terahertz) devices and the huge market potential for THz system have led to an enormous amount of research and development in the area for a number of years. The Gunn Diode is expected to play a significant role in the development of low cost solid state oscillators which will form an essential part of these THz systems.Gunn and mixer diodes will 'power' future THz systems. The THz frequencies generation methodology is based on a two-stage module. The initial frequency source is provided by a high frequency Gunn diode and is the main focus of this work. The output from this diode is then coupled into a multiplier module. The multiplier provides higher frequencies by the generation of harmonics of the input signal by means of a non-linear element, such as Schottky diode Varactor. A realistic Schottky diode model developed in SILVACOTM is presented in this work.This thesis describes the work done to develop predictive models for Gunn Diode devices using SILVACOTM. These physically-based simulations provide the opportunity to increase understanding of the effects of changes to the device's physical structure, theoretical concepts and its general operation. Thorough understanding of device physics was achieved to develop a reliable Gunn diode model. The model development included device physical structure building, material properties specification, physical models definition and using appropriate biasing conditions.The initial goal of the work was to develop a 2D model for a Gunn diode commercially manufactured by e2v Technologies Plc. for use in second harmonic mode 77GHz Intelligent Adaptive Cruise Control (ACC) systems for automobiles. This particular device was chosen as its operation is well understood and a wealth of data is available for validation of the developed physical model. The comparisons of modelled device results with measured results of a manufactured device are discussed in detail. Both the modelled and measured devices yielded similar I-V characteristics and so validated the choice of the physical models selected for the simulations. During the course of this research 2D, 3D rectangular, 3D cylindrical and cylindrical modelled device structures were developed and compared to measured results.The injector doping spike concentration was varied to study its influence on the electric field in the transit region, and was compared with published and measured data.Simulated DC characteristics were also compared with measured results for higher frequency devices. The devices mostly correspond to material previously grown for experimental studies in the development of D-band GaAs Gunn devices. Ambient temperature variations were also included in both simulated and measured data.Transient solutions were used to obtain a time dependent response such as determining the device oscillating frequency under biased condition. These solutions provided modelled device time-domain responses. The time-domain simulations of higher frequency devices which were developed used modelling measured approach are discussed. The studied devices include 77GHz (2nd harmonic), 125 GHz (2nd harmonic) and 100 GHz fundamental devices.During the course of this research, twelve research papers were disseminated. The results obtained have proved that the modelling techniques used, have provided predictive models for novel Transferred Electron Devices (TEDs) operating above 100GHz.

In this thesis, a physics-based single particle modeling is presented to analyze a proposed direct coupled hybrid energy storage modules using lithium-ion battery and ultracapacitor. Firstly, a state of the art for the energy storage system in the electrified vehicles are summarized. Several energy storage elements including lead-acid battery, nickel-metal hydride battery, lithium-ion battery, ultracapacitor, and lithium-ion capacitor are reviewed. Requirements of the energy storage systems in electric, hybrid electric, and plug-in hybrid electric vehicles are generalized. Typical hybrid energy storage system topologies are also reviewed. Moreover, these energy storage elements and hybrid energy storage system topologies are compared to the requirements of the energy storage systems in terms of specific power and specific energy. Secondly, the performance of different battery balancing topologies, including line shunting, ring shunting, synchronous flyback, multi-winding, and dissipative shunting are analyzed based on a linear programming methodology. As a traction battery in an electric or plug-in electric vehicle, high voltage lithium-ion packs are typically configured in a modular fashion, therefore, the analysis considers the balancing topologies at module level and cell level and focuses on minimum balancing time, minimum plug-in charge time, minimum energy loss, and component counts of every balancing topology for the entire battery pack. Thirdly, different modeling techniques for the lithium-ion battery and ultracapacitor are presented. One of the main contributions of this thesis is the development of a physics-based single particle modeling embedded with a solid-electrolyte interface growth model for a lithium-ion battery in battery management system. This development considers the numerical solution of diffusion equation, cell level quantities, parametrization method, effects of number of shells in a spherical particle, SOC-SOH estimation algorithms, and aging effects. The accuracy of the modeling is validated by experimental results of a Panasonic NCR18650A lithium-ion battery cell. Fourthly, the physics-based modeling is applied to analyze the performance of a proposed direct coupled hybrid energy storage module topology based on the Panasonic NCR18650A lithium-ion battery and Maxwell BCAP0350 ultracapacitor. There are many ways to directly connect battery cells and ultracapacitor cells in a module which would influence the performance of the module. The results show that a module has 9 cells in a battery string and 14 cells in an ultracapacitor string can obtain the highest power capability and utilize the most of the energy in an ultracapacitor. More ultracapacitor strings connected in parallel would increase the power density but reduce the energy density. Moreover, the simulation and experimental results indicate that the direct coupled hybrid modules can extend the operating range and slow the capacity fade of lithium-ion battery. An SOC-SOH estimation algorithm for the hybrid module is also developed based on the physics-based modeling. Finally, a pack design methodology is proposed to meet U.S. Advanced Battery Consortium LLC PHEV-40, power-assist, and 48V HEV performance targets for the battery packs or the proposed direct coupled topologies. In order to explore replacement tradeoffs between the battery and ultracapacitor, a case study of the direct coupled topologies is presented. From the case study, ultracapacitors enhance the power capability for short term pulse power and marginally reduce the cost of an entire energy storage system. Moreover, the hybrid module topologies can keep a relatively long all-electric range when the batteries degrade. / Dissertation / Doctor of Philosophy (PhD)

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La simulation médicale interactive sur ordinateur est une technologie révolutionnaire pour améliorer l'efficacité de nombreuses interventions médicales tout en réduisant le niveau de risque pour les patients. Bien que visant essentiellement l'apprentissage, ces simulations pourraient être utilisées, dans un futur proche, pour la planification d'interventions complexes ou même pour assister le praticien / clinicien dans la salle d'opération. Ce manuscrit présente une revue détaillée du domaine multi-disciplinaire de la simulation médicale, et illustre nos différentes contributions dans ce domaine. Après une vue d'ensemble, au Chapitre I, de nombreuses applications en simulation médicale, le Chapitre II décrit nos contributions sur les modèles, depuis la modélisation anatomique (afin de créer des représentations réalistes, et potentiellement adaptées au patient, de l'anatomie humaine) jusqu'à la modélisation biomécanique (pour déterminer les caractéristiques des tissus mous et définir des modèles mathématiques décrivant leur comportement). Les problématiques liées à la modélisation de matériel médical (instruments flexibles ou systèmes d'imagerie) ou encore la modélisation physiologique (pour le calcul d'écoulement sanguin par exemple) sont également abordées. Le Chapitre III s'attache à la modélisation des interactions entre instruments et tissus mous, qui occupent une part très importante dans toute intervention médicale. Les différentes techniques à mettre en oeuvre pour modéliser de telles interactions (détection de collision, modélisation des contacts et rendu haptique) sont décrites dans ce chapitre. Au Chapitre IV sont présentées plusieurs contributions liées à la validation, que ce soit pour comparer des modèles déformables ou pour l'évaluation de systèmes d'apprentissage. Le Chapitre V est dédié à la description de divers prototypes de simulateurs développés au cours de ces travaux de recherche, et le Chapitre VI présente nos récents travaux visant au développement d'une plate-forme Open Source dédiée à la simulation médicale. Cette plate-forme, appelée SOFA, est le fruit d'un travail collaboratif international à travers lequel nous espérons fédérer de nombreuses équipes de recherche. Finalement, le Chapitre VII résume nos différentes contributions et présente un ensemble de perspectives et de défis, en particulier dans les domaine de la simulation et de la planification sur des données spécifiques à des patients.

This research establishes a physics-based life determination model for the second generation single crystal superalloy PWA 1484 experiencing out-of-phase thermomechanical fatigue (TMF). The life model was developed as a result of a combination of critical mechanical tests, dominant damage characterization and utilization of well-established literature. The resulting life model improves life prediction over currently employed methods and provides for extrapolation into yet unutilized operating regimes. Particularly, the proposed deformation model accounts for the materials' coupled fatigue-environment-microstructure response to TMF loading. Because the proposed model is be based upon the underlying deformation physics, the model is robust enough to be easily modified for other single crystal superalloys having similar microstructure. Future use of this model for turbine life estimation calculations would be based upon the actual deformation experienced by the turbine blade, thereby enabling turbine maintenance scheduling based upon on a "retirement for a cause" life management scheme rather than the currently employed "safe-life" calculations. This advancement has the ability to greatly reduce maintenance costs to the turbine end-user since turbine blades would be removed from service for practical and justifiable reasons. Additionally this work will enable a rethinking of the warranty period, thereby decreasing warranty related replacements. Finally, this research provides a more thorough understanding of the deformation mechanisms present in loading situations that combine fatigue-environment-microstructure effects.

A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides the capability to individually monitor and control a wide range of different ES, enabling the extraction of an ES module within a series array to charge or conduct maintenance, while remaining storage can still function to serve a demand. Enhancements and testing of the ESMC are explored in not only interfacing of multiple ES and HESS, but also as a platform to improve management algorithms. There is an imperative need to provide a bridge between the depth of the electrochemical physics of the battery and the power engineering sector, a feat which was accomplished over the course of this work. First, the ESMC was tested on a lead acid battery array to verify its capabilities. Next, physics-based models of lead acid and lithium ion batteries lead to the improvement of both online battery management and established multiple metrics to assess their lifetime, or state of health. Three unique HESS were then tested and evaluated for different applications and purposes. First, a hybrid battery and SC HESS was designed and tested for shipboard power systems. Next, a lithium ion battery and SC HESS was utilized for an electric vehicle application, with the goal to reduce cycling on the battery. Finally, a lead acid battery and flywheel ES HESS was analyzed for how the inclusion of a battery can provide a dramatic improvement in the power quality versus flywheel ES alone.