Dissertations / Theses on the topic 'Space Radioisotope Power Systems'
To see the other types of publications on this topic, follow the link: Space Radioisotope Power Systems.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Space Radioisotope Power Systems.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Langham, Ryan C. "Feasibility study and system architecture of radioisotope thermoelectric generation power systems for usmc forward operating bases." Monterey California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34695.
Full textAbstract:
Approved for public release; distribution is unlimitedThis study sought to identify the feasibility of utilizing a radioisotope thermal (thermoelectric/stirling) generator to provide power to a deployed USMC Expeditionary Force. The conceptual system architecture was constructed through use of the systems engineering process, identifying necessary subsystems and integration boundaries. Radioisotope comparison was then performed, utilizing weighted design factors. It was determined that Sr-90, Cs-137, and Cm-244 would be the most effective fuel sources for this mission area. By analyzing current thermoelectric technology, it was determined that maximum system efficiency is limited to 1015 percent when utilizing available lead telluride thermoelectrics. Barriers to development of identified physical subsystem components were then identified, including health and environmental hazards of potential isotopes, as well as shielding criteria. The system development was found to be feasible and additional design work and development work is proposed.
2
Watkinson, Emily Jane. "Space nuclear power systems : enabling innovative space science and exploration missions." Thesis, University of Leicester, 2017. http://hdl.handle.net/2381/40461.
Full textAbstract:
The European Space Agency’s (ESA’s) 241Am radioisotope power systems (RPSs) research and development programme is ongoing. The chemical form of the americium oxide ‘fuel’ has yet to be decided. The fuel powder will need to be sintered. The size and shape of the oxide powder particles are expected to influence sintering. The current chemical flow-sheet creates lath-shaped AmO2. Investigations with surrogates help to minimise the work with radioactive americium. This study has proposed that certain cubic Ce1-xNdxO2-(x/2) oxides (Ia-3 crystal structures with 0.5 < x < 0.7) could be potential surrogates for some cubic AmO2-(x/2) phases. A new wet-chemical-synthesis-based process for fabricating Ce1-xNdxO2-(x/2) with a targeted x-values has been demonstrated. It uses a continuous oxalate coprecipitation and calcination route. An x of 0.6 was nominally targeted. Powder X-ray diffraction (PXRD) and Raman spectroscopy confirmed its Ia-3 structure. An increase in precipitation temperature (25 °C to 60 °C) caused an increase in oxalate particle median size. Lath/plate-shaped particles were precipitated. Ce Nd oxide PXRD data was Rietveld refined to precisely determine its lattice parameter. The data will be essential for future sintering trials with the oxide where variations in its crystal structure during sintering will be investigated. Sintering investigations with micrometric CeO2 and Nd2O3 have been conducted to understand how AmO2 and Am2O3 may sinter. This is the first reported pure Nd2O3 spark plasma sintering (SPS) investigation. A comparative study on the SPS and the cold-press-and-sinter of CeO2 has been conducted. This is the first study to report sintering lath-shaped CeO2 particles. Differences in their sizes and specific surface areas affected powder cold-pressing and caused variations in cold-pressed-and-sintered CeO2 relative density and Vickers hardness. The targeted density range (85-90%) was met using both sintering techniques. The cold-press-and-sinter method created intact CeO2 discs with reproducible geometry and superior Vickers hardness to those made by SPS.
3
Perez-Davis, Marla Esther. "Heat receivers for solar dynamic space power systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055525095.
Full text
4
Taylor, Gareth Andrew. "A high voltage transmission line for space power systems." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315620.
Full text
5
Presby, Andrew L. "Thermophotovoltaic energy conversion in space nuclear reactor power systems." Thesis, Monterey, Calif. : Naval Postgraduate School, 2004. http://edocs.nps.edu/npspubs/scholarly/theses/2004/Dec/04Dec%5FPresby.pdf.
Full textAbstract:
Thesis (Astronautical Engineer and M. S. in Astronautical Engineering)--Naval Postgraduate School, December 2004.Thesis Advisor(s): Gopinath, Ashok ; Michael, Sherif. "December 2004." Description based on title screen as viewed on March 13, 2009. Includes bibliographical references (p. 123-127). Also available in print.
6
McGinnis, Scott James. "Nuclear power systems for human mission to Mars /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FMcGinnis.pdf.
Full text
7
Arana, Andrew Jex. "Power Systems Analysis in the Power-Angle Domain." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30001.
Full textAbstract:
The idea of performing power systems dynamic analysis in the power-angle domain has been hinted at by previous researchers, but this may be the first published document to develop detailed techniques by which entire power systems can be represented and solved in the power-angle domain. With the widespread deployment of phasor measurement units and frequency data recorders the industry is looking for more real-time analytical tools to turn real-time wide-area measurements into useful information. Applications based on power-angle domain analysis are simple enough that they may be used online.
Power-angle domain analysis is similar to DC load-flow techniques in that a flat voltage profile is used and it is assumed that real power and voltage angle are completely decoupled from reactive power and voltage magnitude. The linearized equations for the dynamics of generators and loads are included in the model, which allows the electromechanical response to be solved using conventional circuit analysis techniques. The effect of generation trips, load switching, and line switching can be quickly approximated with nodal analysis or mesh analysis in the power-angle domain.
The analysis techniques developed here are not intended to be as accurate as time-domain simulation, but they are simpler and fast enough to be put online, and they also provide a better analytical insight into the system. Power-angle domain analysis enables applications that are not readily available with conventional techniques, such as the estimation of electromechanical propagation delays based on system parameters, the formulation of electromechanical equivalents, modal analysis, stability analysis, and event location and identification based on a small number of angle or frequency measurements. Fault studies and contingency analysis are typically performed with detailed time-domain simulations, where the electromechanical
response of the system is a function of every machine in the interconnection and the lines connecting them. All of this information is rarely known for the entire system for each operating condition; as a result, for many applications it may be more suitable to compute an approximation of the system response based on the current operating state of only the major lines and generators. Power-angle domain analysis is adept at performing such approximations.Ph. D.
8
Yuan, Lin. "Design space re-engineering for power minimization in modern embedded systems." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3651.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
9
McGinnis, Scott J. "Nuclear power systems for human mission to Mars." Thesis, Monterey California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1214.
Full textAbstract:
Approved for public release, distribution is unlimitedNuclear power is the next enabling technology in manned exploration of the solar system. Scientists and engineers continue to design multi-megawatt power systems, yet no power system in the 100 kilowatt, electric, range has been built and flown. Technology demonstrations and studies leave a myriad of systems from which decision makers can choose to build the first manned space nuclear power system. While many subsystem engineers plan in parallel, an accurate specific mass value becomes an important design specification, which is still uncertain. This thesis goes through the design features of the manned Mars mission, its power system requirements, their design attributes as well as their design faults. Specific mass is calculated statistically as well as empirically for 1-15MWe systems. Conclusions are presented on each subsystem as well as recommendations for decision makers on where development needs to begin today in order for the mission to launch in the future.
Lieutenant, United States Navy
10
Campbell, Angela Mari. "Architecting aircraft power distribution systems via redundancy allocation." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53087.
Full textAbstract:
Recently, the environmental impact of aircraft and rising fuel prices have become an increasing concern in the aviation industry. To address these problems, organizations such as NASA have set demanding goals for reducing aircraft emissions, fuel burn, and noise. In an effort to reach the goals, a movement toward more-electric aircraft and electric propulsion has emerged. With this movement, the number of critical electrical loads on an aircraft is increasing causing power system reliability to be a point of concern.
Currently, power system reliability is maintained through the use of back-up power supplies such as batteries and ram-air-turbines (RATs). However, the increasing power requirements for critical loads will quickly outgrow the capacity of the emergency devices. Therefore, reliability needs to be addressed when designing the primary power distribution system.
Power system reliability is a function of component reliability and redundancy. Component reliability is often not determined until detailed component design has occurred; however, the amount of redundancy in the system is often set during the system architecting phase. In order to meet the capacity and reliability requirements of future power distribution systems, a method for redundancy allocation during the system architecting phase is needed.
This thesis presents an aircraft power system design methodology that is based upon the engineering decision process. The methodology provides a redundancy allocation strategy and quantitative trade-off environment to compare architecture and technology combinations based upon system capacity, weight, and reliability criteria.
The methodology is demonstrated by architecting the power distribution system of an aircraft using turboelectric propulsion. The first step in the process is determining the design criteria which includes a 40 MW capacity requirement, a 20 MW capacity requirement for the an engine-out scenario, and a maximum catastrophic failure rate of one failure per billion flight hours. The next step is determining gaps between the performance of current power distribution systems and the requirements of the turboelectric system. A baseline architecture is analyzed by sizing the system using the turboelectric system power requirements and by calculating reliability using a stochastic flow network. To overcome the deficiencies discovered, new technologies and architectures are considered. Global optimization methods are used to find technology and architecture combinations that meet the system objectives and requirements. Lastly, a dynamic modeling environment is constructed to study the performance and stability of the candidate architectures. The combination of the optimization process and dynamic modeling facilitates the selection of a power system architecture that meets the system requirements and objectives.
11
Shea, Patrick. "DESIGN AND MODELING OF RADIATION HARDENED LDMOSFET FOR SPACE CRAFT POWER SYSTEMS." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2822.
Full textAbstract:
NASA missions require innovative power electronics system and component solutions with long life capability, high radiation tolerance, low mass and volume, and high reliability in space environments. Presently vertical double-diffused MOSFETs (VDMOS) are the most widely used power switching device for space power systems. It is proposed that a new lateral double-diffused MOSFET (LDMOS) designed at UCF can offer improvements in total dose and single event radiation hardness, switching performance, development and manufacturing costs, and total mass of power electronics systems. Availability of a hardened fast-switching power MOSFET will allow space-borne power electronics to approach the current level of terrestrial technology, thereby facilitating the use of more modern digital electronic systems in space. It is believed that the use of a p+/p-epi starting material for the LDMOS will offer better hardness against single-event burnout (SEB) and single-event gate rupture (SEGR) when compared to vertical devices fabricated on an n+/n-epi material. By placing a source contact on the bottom-side of the p+ substrate, much of the hole current generated by a heavy ion strike will flow away from the dielectric gate, thereby reducing electrical stress on the gate and decreasing the likelihood of SEGR. Similarly, the device is hardened against SEB by the redirection of hole current away from the base of the device's parasitic bipolar transistor. Total dose hardness is achieved by the use of a standard complementary metal-oxide semiconductor (CMOS) process that has shown proven hardness against total dose radiation effects.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
12
Adamovits, Peter J. (Peter Joseph) Carleton University Dissertation Engineering Aerospace. "Model based reasoning applied to the diagnosis of spacecraft electrical power system faults." Ottawa, 1992.
Find full text
13
Zhang, Richard S. "High Performance Power Converter Systems for Nonlinear and Unbalanced Load/Source." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/29314.
Full textAbstract:
This dissertation covers three levels of issues and solutions dealing with unbalanced and/or nonlinear situations in power electronic systems, namely power converter level, power converter system level, and large-scale power electronics system level.
At power converter level, after review of traditional PWM methods, especially two-dimensional space vector modulation schemes, three-dimensional space vector modulation schemes are proposed for four-legged voltage source converters, including inverters and rectifiers. The four-legged power converters with three-dimensional space vector modulation schemes have a better DC link voltage utilization and result in a low distortion. It is an effective solution to provide the neutral point for a three-phase four-wire system and to handle the neutral current due to unbalanced load or source and nonlinear loads. Comprehensive design guidelines for a four-legged inverter are presented. The four-legged rectifier is also presented which allows not only fault tolerant operation, but also provides the flexibility of equal resistance, equal current, or equal power operation under unbalanced source.
Average large-signal models of four-legged power converters in both the a-b-c and d-q-o coordinates are derived. Small signal models are obtained in the d-q-o rotating coordinates. Voltage control loops are designed in the d-q-o coordinates for a high power utility power supply. Performance is studied under various load conditions.
At the power converter system level, the load conditioner concept is proposed for high power applications. A power converter system structure is proposed which consists of a high-power low-switching frequency main inverter and a low-power high-switching frequency load conditioner. The load conditioner performs multiple functions, such as active filtering, active damping, and active decoupling with a high current control bandwidth. This hybrid approach allows the overall system to achieve high performance with high power and highly nonlinear loads.
At the large-scale power electronics system level, the nonlinear loading effect of load converters is analyzed for a DC distribution system. Two solutions to the nonlinear loading effect are presented. One is to confine the nonlinear load effect with the sub-converter system, the other is to use a DC bus conditioner. The DC bus conditioner is the extension of the load conditioner concept.Ph. D.
14
Cho, Bo Hyung. "Modeling and analysis of spacecraft power systems." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54741.
Full textAbstract:
A comprehensive large-scale power system modeling is developed to facilitate the design and analysis of present and future spacecraft power systems. A two-port coupling method is utilized to provide a modularity in model building and analysis of the system. The modular approach allows the model to be flexible, verifiable and computationally efficient. A methodology for the system level analysis is presented with the ability to focus on the performance characteristics of an arbitrary component or subsystem. The system performance parameters are derived explicitly in terms of the two-port hybrid g-parameter representation of the component or subsystem, and impedances of its terminating subsystems. From this, the stability of the system is analytically determined and the subsystem interaction criteria is observed. Also presented is a model development from the empirical data employing the complex curve fitting technique. The technique is especially powerful for large scale system modeling and analysis where certain components and subsystems are viewed as black boxes with measurable terminal characteristics. The technique can also be used to realize a reduced order model of a complex subsystem.
The Direct Energy Transfer (DET) spacecraft power system is modeled to demonstrate the versatility of the comprehensive system model by performing various DC, small-signal and large-signal analyses. Of particular interest is the analysis of the large-signal behavior of the nonlinear solar array system by employing the state-plane method. The analysis of the solar array system operation focused on the transition mode between the shunt mode and the battery discharging mode is presented. The subsystem interaction problems in the local component and global system are illustrated. A methodology for the design and trouble-shooting of a system dealing with the interaction problems using the g-parameters is described. Finally, a system level analysis of the DET system using an empirical data modeling technique is performed.Ph. D.
15
Lee, Jae Ryong. "Analysis and simulation of dynamics of spacecraft power systems." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53568.
Full textAbstract:
Comprehensive analyses, including dc, small-signal and large-signal analyses, of the dynamics of various spacecraft power systems are performed. Systems' dynamics are analyzed for various operating modes, such as the shunt, battery-charge and battery-discharge modes, as well as the transition mode. Computer models using the EASY5 program are developed for the Direct Energy Transfer (DET) system, solar array switching system and partial shunt system to facilitate design, analysis and performance verification.
Large-signal analyses are performed to identify stability conditions and to predict large-signal dynamic behavior for each mode of operation. The equivalent source and load characteristics of a solar array power system with a constant-power load, shunt regulator, battery charger and discharger, are identified to predict large-signal dynamic behavior. Employing the equivalent source and load, the state trajectories of shunt failure, battery discharger failure and solar array/battery lockup are predicted and verified through time-domain simulations.
Small-signal analyses of the DET system are performed for the three modes of operation. The system loop gain is defined. Design guidelines for the feedback control loop of the shunt regulator, battery charger and discharger are developed to shape the system loop gain for the optimum bus dynamic performance and stability of the system. Designed subsystems are simulated both in frequency-domain and time-domain to verify the design concept.
Various spacecraft power systems, such as solar array switching systems, a partial shunt system, a peak power tracking system and the COBE (Cosmic Background Explorer) power system are analyzed and simulated. Design guidelines of the power conditioning equipment for each system are provided.Ph. D.
16
Modi, Sohrab. "Free space laser communications on the Macintosh computers /." Online version of thesis, 1990. http://hdl.handle.net/1850/10547.
Full text
17
Reason, Joseph P. "A comparative study of nuclear technology and direct energy conversion methods for space power systems." Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/8110.
Full textAbstract:
The objectives of this thesis are to investigate the theory of direct energy conversion, research the development of space nuclear power systems, evaluate the status of current systems, and draw conclusions about the feasibility and merit of using nuclear power for future space missions. Development of the earliest systems began in 1955 with the Systems for Nuclear Auxiliary Power (SNAP) Program and Project Rover. A detailed review of system design and performance is provided for the reactors and radioisotope thermoelectric generators (RTG's) of past and current programs. Thermoelectric and thermionic energy conversion techniques have been used predominantly in space nuclear power systems. The theory of these direct energy conversion methods is analyzed. Also, the safety review procedures and regulations governing the launch of nuclear sources into space are characterized. Conclusions compare accomplished levels of system performance to theoretically predicted limits and comment on the usefulness of space nuclear power for space applications
18
Nelms, Robert Mark. "Simulation of spacecraft power systems using a modular state variable approach." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53653.
Full textAbstract:
The power requirements for future spacecraft power systems will be on the order of a few hundred kilowatts to a few megawatts. Because of these power levels, a high-voltage, high-power distribution subsystem may be utilized to transmit power from the source to the different loads. Using current state-of-the-art power conditioning electronics, complex series and parallel configurations will be required at the interface between the source and the distribution subsystem and between the distribution subsystem and the loads.
The dynamic response of such a spacecraft power system may be obtained using a general purpose program such as SPICE2. However, for large and complex spacecraft power systems, the input file will be large and complex with correspondingly large computation times. As an alternative, the spacecraft power system can be considered as an interconnection of modular components. Each component is treated as a two-port network, and a state model is written with the port voltages as the inputs. The state model of each component is solved using the state transition matrix and assuming that the port voltages are . clamped for each time step. This calculation proceeds as if all two-port networks are decoupled. After the state variables have been updated, the inputs to all components are calculated using network analysis principles. The solution procedure alternates between solving the dynamic model of all components and the network equations for the component inputs.
The modular state variable approach and SPICE2 are compared using two example systems. This comparison shows the advantages of the modular state variable approach. First, for the modular state variable approach the system is considered as an interconnection of modular components. In SPICE2, the system is treated as an interconnection of circuit elements. As a result, the system description for large and complex spacecraft power systems is much _ larger and more complex than a modular state variable description. Secondly, the modular state variable approach requires less CPU time than SPICE2. For one of the example systems presented here, the modular state variable approach uses one-twentieth of the CPU time used by SPICE2.Ph. D.
19
Knight, Travis Warren. "Processing of solid solution, mixed uranium/refractory metal carbides for advanced space nuclear power and propulsion systems." [Florida] : State University System of Florida, 2000. http://etd.fcla.edu/etd/uf/2000/amt2444/disert%5F13.pdf.
Full textAbstract:
Thesis (Ph. D.)--University of Florida, 2000.Title from first page of PDF file. Document formatted into pages; contains vii, 167 p.; also contains graphics. Vita. Includes bibliographical references (p. 162-166).
20
Subramanian, Sriram. "Managing space in forward pick areas of warehouses for small parts." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50309.
Full textAbstract:
Many high-volume warehouses for small parts such as pharmaceuticals, cosmetics and office supplies seek to improve efficiency by creating forward pick areas in which many popular products are stored in a small area that is replenished from reserve storage. This thesis addresses the question of how to stock forward pick areas to maximum benefit by answering two key, inter-related decisions that have been called Assignment-Allocation. The assignment question asks which SKUs should be stored in the forward pick area? And the allocation question asks how much space should be allocated to each SKU? We show fast, simple, near-optimal algorithms to answer these questions in a variety of circumstances. To allocate space to SKUS, we introduce a Powers of Two allocation scheme designed to simplify shelf management. In addition, we present a ranking-based algorithm to assign SKUs and allocate space among multiple forward pick areas. We show that a similar algorithm that accounts for constraints on congestion and workload within the forward pick area. We also show how to determine the optimal assignment for warehouses with one or more forward pick areas that allocate space in ways that are common in practice.
Warehouses frequently use the 80-20 rule to manage SKUs based on their popularity. We examine empirical data from thirty warehouses and analyze whether the power law distribution is a suitable fit. We test the hypothesis that the power law fits of warehouses in similar industries are themselves similar. We review explanations for why power laws arise in other settings and identify those that are plausible in the warehouse setting.
21
Chan, John Tak Yan. "An interactive computer graphics package for power system analysis based on two-dimensional projections on the voltge space /." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63787.
Full text
22
Rymut, Joseph E. "Development and Control of a Solar Array Switching Module." Cleveland State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=csu1198769150.
Full text
23
St, Rock Brian Eric. "Thermal-fluid analysis of a lithium vaporizer for a high power magnetoplasmadynamic thruster." Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-010907-142804/.
Full text
24
Yoon, Hyungjoo. "Spacecraft Attitude and Power Control Using Variable Speed Control Moment Gyros." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4850.
Full textAbstract:
A Variable Speed Control Moment Gyro (VSCMG) is a recently
introduced actuator for spacecraft attitude control.
As its name implies, a VSCMG is essentially a single-gimbal
control moment gyro (CMG) with a flywheel allowed to have variable spin
speed. Thanks to its extra degrees of freedom, a
VSCMGs cluster can be used to achieve additional objectives, such
as power tracking and/or singularity avoidance, as well as
attitude control.
In this thesis, control laws for an integrated power/attitude
control system (IPACS) for a satellite using VSCMGs are
introduced.
The power tracking objective is achieved by storing or releasing the kinetic energy
in the wheels. The proposed control algorithms perform both the attitude
and power tracking goals simultaneously.
This thesis also provides a singularity analysis and avoidance method using
CMGs/VSCMGs. This issue is studied for both the cases of attitude tracking with and without a power
tracking requirement. A null motion method to avoid singularities is
presented, and a criterion is developed to determine the momentum region
over which this method will successfully avoid singularities.
The spacecraft angular velocity and attitude control problem using a single
VSCMG is also addressed.
A body-fixed axis is chosen to
be perpendicular to the gimbal axis, and it is controlled to aim at an arbitrarily given inertial direction,
while the spacecraft angular velocity is stabilized.
Finally, an adaptive control algorithm for the spacecraft attitude tracking in case
when the actuator parameters, for instance the spin axis directions, are uncertain is developed.
The equations of motion in this case
are fully nonlinear and represent a Multi-Input-Multi-Output (MIMO) system.
The smooth projection algorithm is applied to keep the parameter estimates inside
a singularity-free region.
The design procedure can also be easily applied to general MIMO dynamical systems.
25
Asif, Samina. "Evolutionary computation based multi-objective design search and optimization of spacecraft electrical power subsystems." Thesis, Connect to e-thesis, 2008. http://theses.gla.ac.uk/373/.
Full text
26
Phan, Anh Tuan. "Power Systems Model Developments for Power Qality Monitoring : Application to Fundamental Frequency and Unbalance Estimation." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH8692/document.
Full textAbstract:
Les énergies renouvelables, l’énergie sous la forme électrique et son transport à l’aide de réseaux électriques intelligents représentent aujourd’hui des enjeux majeurs car ils ont de grands impacts environnementaux et sociétaux. Ainsi, la production, le transport et la gestion de l’énergie électrique, continuent toujours à susciter un intérêt croissant. Pour atteindre ces objectifs, plusieurs verrous technologiques doivent être levés. Au-delà des questions liées aux architectures des réseaux électriques, aux modèles, aux outils de dimensionnement, à la formalisation de caractéristiques et d’indicateurs, aux contraintes et aux critères, à la gestion et à la production décentralisée, la qualité de la puissance électrique est centrale pour la fiabilité de l’ensemble du système de distribution. Les perturbations affectent la qualité des signaux électriques et peuvent provoquer des conséquences graves sur les autres équipements connectés au réseau. Les travaux de cette thèse s’inscrivent dans ce contexte et de fait ils sont orientés vers le développement de modèles, d’indicateurs et de méthodes de traitement des signaux dédiés à la surveillance en temps-réel des performances des réseaux de distribution électrique.Cette thèse analyse la qualité de la puissance électrique, en prenant en compte plusieurs caractéristiques bien connues ainsi que leur pertinence. Les modèles des systèmes électriques et les méthodes de traitement du signal pour estimer leurs paramètres sont étudiés pour des applications en temps-réel de surveillance, de diagnostic et de contrôle sous diverses conditions. Parmi tous, la fréquence fondamentale est l’un des paramètres les plus importants pour caractériser un système de distribution électrique. En effet, sa valeur qui est censée être une constante, varie en permanence et reflète la dynamique de l’énergie électrique disponible. La fréquence peut également être affectée par certaines productions d’énergie renouvelable et peut être influencée par des mauvaises synchronisations de certains équipements. En outre, la puissance absorbée par les charges ou produite par des sources est généralement différente d’une phase à l’autre. Évidemment, la plupart des installations électriques existantes avec plusieurs phases, qu’elles soient résidentielles ou industrielles, travaillent dans des conditions déséquilibrées. Identifier les composantes symétriques de tension est dans ce cas un moyen pertinent pour quantifier le déséquilibre entre les phases d’un système électrique.De nouvelles représentations de type espace d’état et modélisant des systèmes électriques sont proposées pour estimer la fréquence fondamentale et pour identifier les composantes symétriques de tension des systèmes électriques triphasés et déséquilibrés. Le premier modèle d’espace d’état proposé considère la fréquence fondamentale comme connue ou obtenue par un autre estimateur. En contrepartie, il fournit les autres paramètres caractérisant le système électrique. Un second modèle d’état-espace est introduit. Il est original dans le sens où il ne nécessite aucune connaissance de la fréquence fondamentale. Une de ses variables d’état est directement reliée à la fréquence et permet donc de la déduire. En outre, ce nouvel espace d’état est parfaitement capable de représenter des systèmes électriques à trois phases équilibrés et non équilibrés. [...]Renewable energy, electricity and smart grids are core subjects as they have great environmental and societal impacts. Thus, generating, transporting and managing electric energy, i.e., power, still continue to drive a growing interest. In order to properly achieve these goals, several locks must be removed. Beyond issues related to the distribution architecture, the formalization of models, sizing tools, features and indicators, constraints and criteria, decentralized generation and energy management, power quality is central for the whole grid’s reliability. Disturbances affect the power quality and can cause serious impact on other equipment connected to the grid. The work of this thesis is part of this context and focuses on the development of models, indicators, and signal processing methods for power quality monitoring in time-varying power distribution systems.This thesis analyzes the power quality including several well-known features and their relevance. Power system models and signal processing methods for estimating their parameters are investigated for the purpose of real-time monitoring, diagnostic and control tasks under various operating conditions. Among all, the fundamental frequency is one of the most important parameters of a power distribution system. Indeed, its value which is supposed to be a constant varies continuously and reflects the dynamic availability of electric power. The fundamental frequency can also be affected by renewable energy generation and by nasty synchronization of some devices. Moreover, the power absorbed by loads or produced by sources is generally different from one phase to the other one. Obviously, most of the existing residential and industrial electrical installations with several phases work under unbalanced conditions. Identifying the symmetrical components is therefore an efficient way to quantify the imbalance between the phases of a grid. New state-space representations of power systems are proposed for estimating the fundamental frequency and for identifying the voltage symmetrical components of unbalanced three-phase power systems. A first state-space representation is developed by supposing the fundamental frequency to be known or to be calculated by another estimator. In return, it provides other parameters and characteristics from the power system. Another original state-space model is introduced which does not require the fundamental frequency. Here, one state variable is a function of the frequency which can thus be deduced. Furthermore this new state-space model is perfectly are able to represent a three-phase power system in both balanced and unbalanced conditions. This not the case of lots of existing models. The advantage of the proposed state-space representation is that it gives directly access to physical parameters of the system, like the frequency and the amplitude and phase values of the voltage symmetrical components. Power systems parameters can thus be estimated in real-time by using the new state-space with an online estimation process like an Extended Kalman Filter (EKF). The digital implementation of the proposed methods presents small computational requirement, elegant recursive properties, and optimal estimations with Gaussian error statistics.The methods have been implemented and validated through various tests respecting real technical constraints and operating conditions. The methods can be integrated in active power filtering schemes or load-frequency control strategies to monitor power systems and to compensate for electrical disturbances
27
Zwahlen, Jurg C. "Investigation or a pulsed plasma thruster plume using a quadruple Langmuir probe technique." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0108103-143841.
Full text
28
Vazquez, Ramos Gabriel. "Wireless Power Transfer for Space Applications: System Design and Electromagnetic Compatibility Compliance of Radiated Emissions." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5546.
Full textAbstract:
This dissertation evaluates the possibility of wireless power transfer (WPT) systems for space applications, with an emphasis in launch vehicles (rockets). After performing literature review for WPT systems, it was identified that magnetic resonance provides the more suited set of characteristics for this application. Advanced analysis, simulation and testing were performed to magnetic resonance WPT systems to acquire system performance insight. This was accomplished by evaluating/varying coupling configuration, load effects and magnetic element physical characteristics (i.e. wire material, loop radius, etc.). It was identified by analysis, circuit simulation and testing that the best coupling configuration for this application was series-series and series-shunt with Litz wire loop inductors.
The main concern identified for the implementation of these systems for space applications was radiated emissions that could potentially generate electromagnetic interference (EMI). To address this EMI concern, we developed the Electromagnetic Compatibility Radiated Emissions Compliance Design Evaluation Approach for WPT Space Systems. This approach systematically allocates key analyses, simulations and tests procedures to predict WPT EMC compliance to NASA’s EMC standard Mil-Std-461E/F. Three prototype/magnetic elements were successfully assessed by implementing the WPT EMC design approach. The electric fields intensity generated by the WPT prototypes/magnetic elements tested were: 30.02 dB[micro]V/m, 28.90 dB[micro]V/m and 82.13 dB[micro]V/m (requirement limit: 140 dB[micro]V/m). All three prototypes successfully transferred power wirelessly and successfully met the NASA EMC requirements.ID: 031001541; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Jiann S. Yuan.; Title from PDF title page (viewed August 21, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 140-145).
Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
29
Carbone, Marc A. Carbone. "Development of a Supervisory Tool for Fault Detection and Diagnosis of DC Electric Power Systems with the Application of Deep Space Vehicles." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1601984256665471.
Full text
30
Gärdsback, Mattias. "Deployment Control of Spinning Space Webs and Membranes." Doctoral thesis, KTH, Strukturmekanik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9574.
Full textAbstract:
Future solar sail and solar power satellite missions require deployment of large and lightweight flexible structures in space. One option is to spin the assembly and use the centrifugal force for deployment, stiffening and stabilization. Some of the main advantages with spin deployment are that the significant forces are in the plane of rotation, a relatively simple control can be used and the tension in the membrane or web can be adjusted by the spin rate to meet the mission requirements. However, a successful deployment requires careful development of new control schemes. The deployment rate can be controlled by a torque, applied either to a satellite in the center or by thrusters in the corners, or by deployment rate control, obtained by tether, spool braking or folding properties. Analytical models with only three degrees of freedom were here used to model the deployment of webs and membranes for various folding patterns and control schemes, with focus on space webs folded in star-like arms coiled around a center hub. The model was used to investigate control requirements and folding patterns and to obtain optimal control laws for centrifugal deployment. New control laws were derived from the optimal control results and previously presented control strategies. Analytical and finite element simulations indicate that the here developed control laws yield less oscillations, and most likely more robustness, than existing controls. Rotation-free (RF) shell elements can be used to model inflation or centrifugal deployment of flexible memebrane structures by the finite element method. RF elements approximate the rotational degrees of freedom from the out-of-plane displacements of a patch of elements, and thus avoid common singularity problems for very thin shells. The performance of RF shell elements on unstructured grids is investigated in the last article of this thesis, and it is shown that a combination of existing RF elements performs well even for unstructured grids.QC 20100729
31
Byrne, Lawrence Thomas. "Langmuir probe measurements in the plume of a pulsed plasma thruster." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-1219102-173938.
Full textAbstract:
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: PPT; pulsed plasma thruster; Langmuir probe; plasma diagnostics; electric propulsion; electron temperature; electron density. Includes bibliographical references (p. 97-102).
32
Scruggs, James N. "Power system availability determination through Petri net simulation." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1178910568.
Full text
33
Zwahlen, Jurg C. "Investigation of a Pulsed Plasma Thruster Plume Using a Quadruple Langmuir Probe Technique." Digital WPI, 2003. https://digitalcommons.wpi.edu/etd-theses/33.
Full textAbstract:
The rectangular pulsed plasma thruster (PPT) is an electromagnetic thruster that ablates Teflon propellant to produce thrust in a discharge that lasts 5-20 microseconds. In order to integrate PPTs onto spacecraft, it is necessary to investigate possible thruster plume-spacecraft interactions. The PPT plume consists of neutral and charged particles from the ablation of the Teflon fuel bar as well as electrode materials. In this thesis a novel application of quadruple Langmuir probes is implemented in the PPT plume to obtain electron temperature, electron density, and ion speed ratio measurements (ion speed divided by most probable thermal speed). The pulsed plasma thruster used is a NASA Glenn laboratory model based on the LES 8/9 series of PPTs, and is similar in design to the Earth Observing-1 satellite PPT. At the 20 J discharge energy level, the thruster ablates 26.6 mg of Teflon, creating an impulse bit of 256 mN-s with a specific impulse of 986 s. The quadruple probes were operated in the so-called current mode, eliminating the need to make voltage measurements. The current collection to the parallel to the flow electrodes is based on Laframboise's theory for probe to Debye length ratios between 5 and 100, and on the thin-sheath theory for ratios above 100. The ion current to the perpendicular probe is based on a model by Kanal and is a function of the ion speed ratio, the applied non-dimensional potential and the collection area. A formal error analysis is performed using the complete set of nonlinear current collection equations. The quadruple Langmuir probes were mounted on a computer controlled motion system that allowed movement in the radial direction, and the thruster was mounted on a motion system that allowed angular variation. Measurements were taken at 10, 15 and 20 cm form the Teflon fuel bar face, at angles up to 40 degrees off of the centerline axis at discharge energy levels of 5, 20, and 40 J. All data points are based on an average of four PPT pulses. Data analysis shows the temporal and spatial variation in the plume. Electron temperatures show two peaks during the length of the pulse, a trend most evident during the 20 J and 40 J discharge energies at 10 cm from the surface of the Teflon fuel bar. The electron temperatures after the initial high temperature peak are below 2 eV. Electron densities are highest near the thruster exit plane. At 10 cm from the Teflon surface, maximum electron densities are 1.04e20 ± 2.8e19 m-3, 9.8e20 ± 2.3e20 m-3, and 1.38e21 ± 4.05e20 m-3 for the 5 J, 20 J and 40 J discharge energy, respectively. The electrons densities decrease to 2.8x1019 ± 8.9e18 m-3, 1.2e20 ± 4.2e19 m-3, and 4.5e20 ± 1.2e20 m-3 at 20 cm for the 5 J, 20 J, and 40 J cases, respectively. Electron temperature and density decrease with increasing angle away from the centerline, and with increasing downstream distance. The plume is more symmetric in the parallel plane than in the perpendicular plane. Ion speed ratios are lowest near the thruster exit, increase with increasing downstream distance, but do not show any consistent angular variation. Peak speed ratios at a radial distance of 10 cm are 5.9±3.6, 5.3±0.39, and 4.8±0.41 for the 5 J, 20 J and 40 J discharge energies, respectively. The ratios increase to 6.05±5.9, 7.5±1.6, and 6.09±0.72 at a radial distance of 20 cm. Estimates of ion velocities show peak values between 36 km/s to 40 km/s, 26 km/s to 30 km/s, and 26 km/s to 36 km/s for the % J, 20 J, and 40 J discharge energies, respectively.
34
Cimaroli, Alexander J. "Development of Deposition and Characterization Systems for Thin Film Solar Cells." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481295690696407.
Full text
35
Cheney, Liam Jon. "Development of Safety Standards for CubeSat Propulsion Systems." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1180.
Full textAbstract:
The CubeSat community has begun to develop and implement propulsion systems. This movement represents a new capability which may satisfy mission needs such as orbital and constellation maintenance, formation flight, de-orbit, and even interplanetary travel. With the freedom and capability granted by propulsion systems, CubeSat providers must accept new responsibilities in proportion to the potential hazards that propulsion systems may present.
The Cal Poly CubeSat program publishes and maintains the CubeSat Design Specification (CDS). They wish to help the CubeSat community to safety and responsibly expand its capabilities to include propulsive designs. For this reason, the author embarked on the task of developing a draft of safety standards CubeSat propulsion systems.
Wherever possible, the standards are based on existing documents. The author provides an overview of certain concepts in systems safety with respect to the classification of hazards, determination of required fault tolerances, and the use of inhibits to satisfy fault tolerance requirements. The author discusses hazards that could exist during ground operations and through launch with respect to hazardous materials and pressure systems. Most of the standards related to Range Safety are drawn from AFSPCMAN 91-710. Having reviewed a range of hypothetical propulsion system architectures with an engineer from Range Safety at Vandenberg Air Force Base, the author compiled a case study. The author discusses many aspects of orbital safety. The author discusses the risk of collision with the host vehicle and with third party satellites along with the trackability of CubeSats using propulsion systems. Some recommendations are given for working with the Joint Functional Component Command for Space (JFCC SPACE), thanks to the input of two engineers who work with the Joint Space Operations Center (JSpOC). Command Security is discussed as an important aspect of a mission which implements a propulsion system. The author also discusses End-of-Life procedures such as safing and de-orbit operations. The orbital safety standards are intended to promote “good citizenship.”
The author steps through each proposed standard and offers justification. The author is confident that these standards will set the stage for a dialogue in the CubeSat community which will lead to the formulation of a reasonable and comprehensive set of standards. The author hopes that the discussions given throughout this document will help CubeSat developers to visualize the path to flight readiness so that they can get started on the right foot.
36
Hobdell, Stephen Barry. "Thermally stimulated current and electrokinetic investigations of HV cable models." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311421.
Full text
37
Green, Robert C. II. "Novel Computational Methods for the Reliability Evaluation of Composite Power Systems using Computational Intelligence and High Performance Computing Techniques." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1338894641.
Full text
38
Jung, Jin Woo. "Modeling and control of fuel cell based distributed generation systems." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1116451881.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvi, 209 p.; also includes graphics. Includes bibliographical references (p. 202-209). Available online via OhioLINK's ETD Center
39
Ariño, i. Prats Andreu. "Physics of the Intergalactic Medium: a Study of the Power Spectrum ot the Lyman Alpha Forest and the Metal Content of Damped Lyman Alpha Systems." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/289625.
Full textAbstract:
El Medi Intergalàctic permet una caracterització de propietats bàsiques de l'univers tals com paràmetres fonamentals del model cosmològic, el creixement de pertorbacions primordials de densitat i formació de galàxies. Aquesta caracterització s'assoleix mitjançant l'absorció de la llum per part del Medi Intergalàctic a l'espectre d'espectres d'objectes llunyans i lluminosos.
Tot això ens motiva considerar dos aspectes del Medi Intergalàctic: primerament utilitzarem simulacions numèriques i models teòric per comprendre les complexitats de la evolució no lineal del medi intergalàctic. D'altra banda l'ús d'un extens catàleg de sistemes d'absorció en espectres quasars proveïdes pel sondeig astronòmic anomenat Bariònic Oscillation Spectroscopic Survey (BOSS).
Per una part cal entendre tots els processos complexos que ocorren al medi intergalàctic, per això és necessari l'ús de simulacions hidrodinàmiques que permeten el seu modelat. S'ha procedit a extraure l'espectre de potències de la fracció transmesa a través de l'hidrogen atòmic d'un gran nombre de simulacions cosmològiques. Aquest espectre de potencies s'ha descrit acuradament amb una model teòric, el qual amb pocs paràmetres és capaç de ajustar les dades i permet fer prediccions i comparacions. En particular paràmetre de biaix que determina l'amplitud de l'espectre de potencies del bosc Lyα i distorsió deguda al redshift han segut fetes per a nombroses simulacions amb diferents cosmologies i propietats físiques.
Per l'altra part el catàleg de dades de BOSS que disposa de més de trenta-mil sistemes d'alta absorció, o sistemes Lyα esmorteïts (DLAs, sigles en anglès), permet l'estudi detallat d'aquests. Els DLAs són denses reserves de gas clau per a la formació de galàxies i permeten traçar propietats cosmològiques. Aleshores s'ha procedit a fer un nou estudi en que es mesuren diverses amplades equivalents dels les línies d'absorció d'elements pesats associats al DLA. S'han combinat diverses línies a un nou paràmetre que s'anomenat “força metàl·lica”, la qual cosa permet obtenir informació d'una combinació de la dispersió de velocitats i metal·licitat per DLAs. Amb aquest mètode s'ha realitzat una classificació d'aquestos segons el nou paràmetre, que permet vore l'espectre conjunt per diferents poblacions, i així les seues propietats mitjanes. S'ha estudiat la evolució de la ”força metàl·lica” amb el redshift, que permetria una comparació amb models i simulacions. Finalment es podrà utilitzar per estudiar la variació del factor de biaix dels DLAs depenent de la nova parametrització.The Intergalactic Medium (IGM), by means the Lyα absorption in quasar spectra ( this is called Lyα forest), is a unique tool allowing the study of the large scales of the universe, which in this way constrains several cosmological, the growth factor of the structure. Moreover the IGM also plays primordial role in galaxy formation. Understanding the physics of the IGM and the way non-linear processes affect the observed Lyα forest, hydrodynamical simulations are necessary because the non linear evolution of the physics cannot be treated in any analytic framework. At the same time, a large number of observations, which have been obtained from the Barionic Oscilation Spectrographic survey (BOSS) to be used in thesis allow studding in unprecedented large number of Lyα forest from quasar spectra, allowing to achieve major breakthroughs. In the 2nd chapter of this thesis we describe the methodology that we developed to extract the power spectrum from the transmission flux of the Hydrodynamical simulations. Using a set of simulations provided by various collaborators we study the effects of various simulation characteristics, such as resolution, box size, particles, and cell division, to see how they might affect the extracted power spectrum. Then we proceed to develop a model to fit the power spectrum of each of the simulations and in this way see the effects of different simulation and physical properties on the predictions from the power spectrum. Once the model fit has been obtained, the non linear power spectrum of the transmission can be related on the matter power spectrum, which on the form of its biased relation with the matter power spectrum contains the cosmological information. This relation is measured by the bias and redshift distortions that can be directly measured from simulations, making predictions for these values that could be later tested with the observations. In the 3rd chapter we use the data from the large catalogue of Damped Lyα systems (DLAs) provided by BOSS. These DLAs, broad regions of completely absorbed flux in the spectra of about 10% of the high redshift objects, the quasars. The DLAs are a large repository of neutral hydrogen, that is why they absorb all the flux that corresponds to their redshift. Since there is so much Neutral Hydrogen the absorption is damped, meaning that wavelength close to the one of the DLA also get absorbed, forming characteristic Lorenz wings that are sensitive to the column density of Hydrogen of the DLA. DLAs are interesting objects that are expected to be very relevant for galaxy formation, and also because they trace the large structure, therefore also being relevant for cosmology. They are, similarly to IGM of which they form part, a bridge between the large cosmological framework and the galaxies that populate the universe. The BOSS survey has allowed us for the first time have a set of thousands of DLAs. Given this amount of data and the interest of the DLAs, we developed a new method and a new parameterization to study the DLAs in the framework of large surveys such as BOSS. First we constructed a method to measure the equivalent width of several metal absorption lines associated with each DLA, even if individually they are not detected because they can not be observed due to the noise and resolution of the spectrum. The equivalent width are combined in a newly defined parameter called Metal Strength, which is a an optimal combination of the equivalent width of the metals measured for a DLA. This classification can then have many applications to measure the mean stack, mean bias and mean redshift evolution with respect this new parameter. The Metal Strength is therefore used to analyse the evolution and characteristics of the various populations of DLAs.
40
Ghasemi, Negareh. "Improving ultrasound excitation systems using a flexible power supply with adjustable voltage and frequency to drive piezoelectric transducers." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/61091/1/Negareh_Ghasemi_Thesis.pdf.
Full textAbstract:
The ability of a piezoelectric transducer in energy conversion is rapidly expanding in several applications. Some of the industrial applications for which a high power ultrasound transducer can be used are surface cleaning, water treatment, plastic welding and food sterilization. Also, a high power ultrasound transducer plays a great role in biomedical applications such as diagnostic and therapeutic applications. An ultrasound transducer is usually applied to convert electrical energy to mechanical energy and vice versa. In some high power ultrasound system, ultrasound transducers are applied as a transmitter, as a receiver or both. As a transmitter, it converts electrical energy to mechanical energy while a receiver converts mechanical energy to electrical energy as a sensor for control system. Once a piezoelectric transducer is excited by electrical signal, piezoelectric material starts to vibrate and generates ultrasound waves. A portion of the ultrasound waves which passes through the medium will be sensed by the receiver and converted to electrical energy. To drive an ultrasound transducer, an excitation signal should be properly designed otherwise undesired signal (low quality) can deteriorate the performance of the transducer (energy conversion) and increase power consumption in the system. For instance, some portion of generated power may be delivered in unwanted frequency which is not acceptable for some applications especially for biomedical applications.
To achieve better performance of the transducer, along with the quality of the excitation signal, the characteristics of the high power ultrasound transducer should be taken into consideration as well. In this regard, several simulation and experimental tests are carried out in this research to model high power ultrasound transducers and systems. During these experiments, high power ultrasound transducers are excited by several excitation signals with different amplitudes and frequencies, using a network analyser, a signal generator, a high power amplifier and a multilevel converter. Also, to analyse the behaviour of the ultrasound system, the voltage ratio of the system is measured in different tests. The voltage across transmitter is measured as an input voltage then divided by the output voltage which is measured across receiver. The results of the transducer characteristics and the ultrasound system behaviour are discussed in chapter 4 and 5 of this thesis.
Each piezoelectric transducer has several resonance frequencies in which its impedance has lower magnitude as compared to non-resonance frequencies. Among these resonance frequencies, just at one of those frequencies, the magnitude of the impedance is minimum. This resonance frequency is known as the main resonance frequency of the transducer. To attain higher efficiency and deliver more power to the ultrasound system, the transducer is usually excited at the main resonance frequency. Therefore, it is important to find out this frequency and other resonance frequencies. Hereof, a frequency detection method is proposed in this research which is discussed in chapter 2.
An extended electrical model of the ultrasound transducer with multiple resonance frequencies consists of several RLC legs in parallel with a capacitor. Each RLC leg represents one of the resonance frequencies of the ultrasound transducer. At resonance frequency the inductor reactance and capacitor reactance cancel out each other and the resistor of this leg represents power conversion of the system at that frequency. This concept is shown in simulation and test results presented in chapter 4.
To excite a high power ultrasound transducer, a high power signal is required. Multilevel converters are usually applied to generate a high power signal but the drawback of this signal is low quality in comparison with a sinusoidal signal. In some applications like ultrasound, it is extensively important to generate a high quality signal. Several control and modulation techniques are introduced in different papers to control the output voltage of the multilevel converters. One of those techniques is harmonic elimination technique. In this technique, switching angles are chosen in such way to reduce harmonic contents in the output side. It is undeniable that increasing the number of the switching angles results in more harmonic reduction. But to have more switching angles, more output voltage levels are required which increase the number of components and cost of the converter. To improve the quality of the output voltage signal with no more components, a new harmonic elimination technique is proposed in this research. Based on this new technique, more variables (DC voltage levels and switching angles) are chosen to eliminate more low order harmonics compared to conventional harmonic elimination techniques. In conventional harmonic elimination method, DC voltage levels are same and only switching angles are calculated to eliminate harmonics. Therefore, the number of eliminated harmonic is limited by the number of switching cycles. In the proposed modulation technique, the switching angles and the DC voltage levels are calculated off-line to eliminate more harmonics. Therefore, the DC voltage levels are not equal and should be regulated. To achieve this aim, a DC/DC converter is applied to adjust the DC link voltages with several capacitors. The effect of the new harmonic elimination technique on the output quality of several single phase multilevel converters is explained in chapter 3 and 6 of this thesis.
According to the electrical model of high power ultrasound transducer, this device can be modelled as parallel combinations of RLC legs with a main capacitor. The impedance diagram of the transducer in frequency domain shows it has capacitive characteristics in almost all frequencies. Therefore, using a voltage source converter to drive a high power ultrasound transducer can create significant leakage current through the transducer. It happens due to significant voltage stress (dv/dt) across the transducer. To remedy this problem, LC filters are applied in some applications. For some applications such as ultrasound, using a LC filter can deteriorate the performance of the transducer by changing its characteristics and displacing the resonance frequency of the transducer. For such a case a current source converter could be a suitable choice to overcome this problem. In this regard, a current source converter is implemented and applied to excite the high power ultrasound transducer. To control the output current and voltage, a hysteresis control and unipolar modulation are used respectively. The results of this test are explained in chapter 7.
41
Costa, Eduardo Coelho Marques da. "Proposta de uma metodologia aprimorada para modelagem de linhas de transmissão no espaço de estados." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260920.
Full textAbstract:
Orientadores: José Pissolato Filho, Sérgio KurokawaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-22T00:02:34Z (GMT). No. of bitstreams: 1 Costa_EduardoCoelhoMarquesda_D.pdf: 1639814 bytes, checksum: 41a5776b46ed850ac50a5bc6db923da7 (MD5) Previous issue date: 2013
Resumo: Uma metodologia alternativa e aprimorada para modelagem de linhas de transmissão multifásicas é apresentada ao longo do desenvolvimento proposto. O desacoplamento modal das fases e cabos pára-raios dá-se por meio de uma metodologia otimizada no uso das matrizes de transformação modal ao longo das sucessivas transformações entre os domínios dos modos e das fases, eliminando os erros decorrentes da modelagem e representação da linha fazendo uso de análise modal. A representação equivalente de cada modo de propagação é desenvolvida por elementos discretos convencionais com base na teoria fundamental de circuitos elétricos, o que torna a modelagem em questão simplificada, porém não menos precisa. Para modelagem do efeito da frequência nos parâmetros longitudinais da linha, é utilizado vector fitting para sintetizar os parâmetros de forma equivalente e por elementos discretos para cada modo de propagação do sistema multifásico. O sistema de equações diferenciais é representado no espaço de estados e facilmente solucionado por métodos numéricos de integração. No entanto, propõe-se a resolução do sistema de equações de estado por meio de um método de solução analítico, significativamente mais eficaz computacionalmente e mais robusto que o método de integração trapezoidal, amplamente aplicado na simulação de transitórios eletromagnéticos. Ademais, o método analítico possibilita o desenvolvimento de uma metodologia híbrida, adequada tanto na simulação de fenômenos transitórios quanto na simulação fenômenos em regime permanente. O modelo proposto é totalmente desenvolvido no domínio do tempo, sem a utilização de transformadas inversas e convoluções, tornando simples a integração de outros dispositivos e elementos não lineares ao longo da linha. Por fim, um processo utilizando FIR digital filtering integrado à modelagem por matrizes de estado, elimina todas as oscilações espúrias decorrentes da discretização da linha por elementos discretos e erros de truncamento. Em suma, o modelo computacional proposto apresenta uma metodologia aprimorada que se estender desde a modelagem dos parâmetros elétricos da linha à simulação propriamente dita dos transitórios eletromagnéticos, na ordem de poucos milissegundos, e fenômenos transitórios mais lentos, próximos do sinal fundamental em regime permanente
Abstract: An alternative and accurate methodology to model multiphase transmission lines is presented in the proposed development. The modal decoupling of the phases and shield wires is given by an optimized methodology in the use of the modal transformation matrix through the successive transformations between modal and phase domains, correcting the errors associated with the modeling and representation of the line by using analysis modal. Each propagation mode is represented by conventional lumped elements widely approached in the electrical circuit theory, which simplify the equivalent modeling, although a no less accurate procedure. To insert the frequency dependence of the longitudinal parameters in the line model, the vector fitting is applied to synthesize the parameters by an equivalent lumped circuit for each propagation mode of the multiphase system. The system of differential equations, resulting from the differential equations associated with the modal parameters, is represented in the state space and easily solved by numeric integration methods. Although, an analytical solution method is proposed to solve the system of state equations. This solution method is more efficient in computational terms and more robust than the well-known trapezoidal rule, widely used for simulation of electromagnetic transients. Furthermore, the proposed analytical method enables the development of a hybrid methodology, properly adapted to simulate transients as well as steady-state phenomena. The proposed model is completely developed in the time domain, without the use of inverse transforms and convolutions, which means that the proposed modeling is totally compatible with any other power electrical devices and nonlinear elements modeled in the time domain. Finally, a process using FIR digital filtering integrated to the modeling by state matrices eliminates all the spurious oscillations occurred from the line parameters discretization and truncation errors. In short, the proposed computational model presents an improved methodology carried out since the line electrical parameters modeling up to the simulation of electromagnetic transients of a few microseconds up to slow transient phenomena, close of the steady-state fundamental signal
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
42
Lunde, Dominic Charles. "A Homegrown DSMC-PIC Model for Electric Propulsion." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2066.
Full textAbstract:
Powering spacecraft with electric propulsion is becoming more common, especially in CubeSat-class satellites. On account of the risk of spacecraft interactions, it is important to have robust analysis and modeling tools of electric propulsion engines, particularly of the plasma plume. The Navier-Stokes equations used in classic continuum computational fluid dynamics do not apply to the rarefied plasma, and therefore another method must be used to model the flow. A good solution is to use the DSMC method, which uses a combination of particle modeling and statistical methods for modeling the simulated molecules. A DSMC simulation known as SINATRA has been developed with the goal to model electric propulsion plumes. SINATRA uses an octree mesh, is written in C++, and is designed to be expanded by further research. SINATRA has been initially validated through several tests and comparisons to theoretical data and other DSMC models. This thesis examines expanding the functionality of SINATRA to simulate charged particles and make SINATRA a DSMC-PIC hybrid. The electric potential is calculated through a 7-point 3D stencil on the mesh nodes and solved with a Gauss-Seidel solver. It is validated through test cases of charged particles to demonstrate the accuracy and capabilities of the model. An ambipolar diffusion test case is compared to a neutral diffusion case and the electric field is shown to stabilize the diffusion rate. A steady state flow test case shows the simulation is able to stabilize and solve the electric potential for a plume-like scenario. It includes additional features to simplify further research including a comprehensive user manual, industry-standard version control, text file inputs, GUI control, and simple parallelism of the simulation. Compilation and execution are standardized to be simple and platform independent to allow longevity of the code base. Finally, the execution bottlenecks of linking particles to cells and particle moving were removed to reduce the simulation time by 95%.
43
Hollman, Jorge. "Step by step eigenvalue analysis with EMTP discrete time solutions." Thesis, University of British Columbia, 2006. http://hdl.handle.net/2429/67.
Full textAbstract:
The present work introduces a methodology to obtain a discrete time state space representation of an electrical network using the nodal [G] matrix of the Electromagnetic Transients Program (EMTP) solution. This is the first time the connection between the EMTP nodal analysis solution and a corresponding state-space formulation is presented. Compared to conventional state space solutions, the nodal EMTP solution is computationally much more efficient. Compared to the phasor solutions used in transient stability analysis, the proposed approach captures a much wider range of eigenvalues and system operating states. A fundamental advantage of extracting the system eigenvalues directly from the EMTP solution is the ability of the EMTP to follow the characteristics of nonlinearities. The system's trajectory can be accurately traced and the calculated eigenvalues and eigenvectors correctly represent the system's instantaneous dynamics. In addition, the algorithm can be used as a tool to identify network partitioning subsystems suitable for real-time hybrid power system simulator environments, including the implementation of multi-time scale solutions. The proposed technique can be implemented as an extension to any EMTP-based simulator. Within our UBC research group, it is aimed at extending the capabilities of our real-time PC-cluster
Object Virtual Network Integrator (OVNI) simulator.
44
Gilles, Paul M. "Performance Enhancement and Characterization of an Electromagnetic Railgun." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2107.
Full textAbstract:
Collision with orbital debris poses a serious threat to spacecraft and astronauts. Hypervelocity impacts resulting from collisions mean that objects with a mass less than 1g can cause mission-ending damage to spacecraft. A means of shielding spacecraft against collisions is necessary. A means of testing candidate shielding methods for their efficacy in mitigating hypervelocity impacts is therefore also necessary. Cal Poly’s Electromagnetic Railgun was designed with the goal of creating a laboratory system capable of simulating hypervelocity (≥ 3 km/s) impacts. Due to several factors, the system was not previously capable of high-velocity (≥ 1 km/s) tests. A deficient projectile design is revised, and a new design is tested. The new projectile design is demonstrated to enable far greater performance than the previous design, with a muzzle velocity ≥ 1 km/sbeing verified during testing, and an energy conversion efficiency of 2.7%. A method of improving contact and controlling wear at the projectile/rail interface using silver plating and conductive silver paste is validated. A mechanism explaining the problem of internal arcing within the railgun barrel is proposed, and design recommendations are made to eliminate arcing on the basis of the work done during testing. The primary structural members are found to be deficient for their application and a failure analysis of a failed member, loading analysis of the railgun barrel, and design of new structures is undertaken and presented.
45
Sunny, Ajin. "SINGLE-DEGREE-OF-FREEDOM EXPERIMENTS DEMONSTRATING ELECTROMAGNETIC FORMATION FLYING FOR SMALL SATELLITE SWARMS USING PIECEWISE-SINUSOIDAL CONTROLS." UKnowledge, 2019. https://uknowledge.uky.edu/me_etds/146.
Full textAbstract:
This thesis presents a decentralized electromagnetic formation flying (EMFF) control method using frequency-multiplexed sinusoidal control signals. We demonstrate the EMFF control approach in open-loop and closed-loop control experiments using a single-degree-of-freedom testbed with an electromagnetic actuation system (EAS). The EAS sense the relative position and velocity between satellites and implement a frequency-multiplexed sinusoidal control signal. We use a laser-rangefinder device to capture the relative position and an ARM-based microcontroller to implement the closed-loop control algorithm. We custom-design and build the EAS that implements the formation control in one dimension. The experimental results in this thesis demonstrate the feasibility of the decentralized formation control algorithm between two satellites.
46
Maniglia, Jeffrey J. Jr. "Design, Fabrication, and Testing of an EMR Based Orbital Debris Impact Testing Platform." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/956.
Full textAbstract:
This paper describes the changes made from Cal Poly’s initial railgun system, the Mk. 1 railgun, to the Mk. 1.1 system, as well as the design, fabrication, and testing of a newer and larger Mk. 2 railgun system. The Mk. 1.1 system is developed as a more efficient alteration of the original Mk. 1 system, but is found to be defective due to hardware deficiencies and failure, as well as unforeseen efficiency losses. A Mk. 2 system is developed and built around donated hardware from the Naval Postgraduate School. The Mk. 2 system strove to implement an efficient, augmented, electromagnetic railgun and projectile system capable of firing an approximate 1g aluminum projectile to speeds exceeding 2 km/s. A novel three part projectile is proposed to mitigate rail and projectile degradation. Projectile and sabot system kinematic equations are derived and the projectile is designed and tested along with Mk. 2 barrel. A numerical electromechanical model is developed to predict the performance of the Mk. 2 system and projectile assembly, and predicts a final velocity for the fabricated system exceeding 3.5 km/s and an efficiency as high as 24%. Testing of the Mk. 2 system showed catastrophic failure of the projectile during initial acceleration, resulting in very short acceleration times and distance, low velocity projectiles, and low efficiencies. During further testing of various projectile configurations, the barrel structure failed due to a large internal arc. Future work for the Mk. 2 system is discussed, a revised external barrel structure suggested, and a solid, more conventional solid chevron projectile design suggested.
47
Pou, Félix Josep. "Modulation and control of three-phase PWM multilevel converters." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/6327.
Full textAbstract:
La present tesi doctoral estudia els inversors trifàsics multinivell del tipus denominat de díodes de fixació (diode-clamped converters). Aquests convertidors poden generar tres o més nivells de tensió a cada fase de sortida, i normalment s'apliquen a sistemes de gran potència ja que poden treballar amb tensions majors que els inversors clàssics. L'anàlisi es centra fonamentalment en la topologia de tres nivells, tot i que també es realitzen contribucions per a convertidors de més nivells. Els principals objectius són la proposta de nous algorismes de modulació vectorial PWM de processat ràpid, l'estudi i la compensació dels efectes dels desequilibris de les tensions dels condensadors del bus de continua, i l'anàlisi de llaços de control avançat.S'han desenvolupat diversos models que han permès obtenir resultats de simulació de les tècniques de modulació i control proposades. A més, gràcies a l'estada d'un any de l'autor al Center for Power Electronics Systems (CPES) a Virginia Tech, USA, la tesi també inclou resultats experimentals que consoliden les conclusions i metodologies presentades. Les principals contribucions es resumeixen a continuació.
Es presenta un nou algorisme de modulació vectorial PWM que aprofita simetries del diagrama vectorial per a reduir el temps de processat. S'analitzen i es quantifiquen les oscil·lacions de tensió de baixa freqüència que apareixen en el punt central dels condensadors del convertidor de tres nivells. Aquesta informació permet dimensionar els condensadors donades les especificacions d'una determinada aplicació.
L'algorisme de modulació també s'aplica a convertidors de més nivells. Pel cas concret del convertidor de quatre nivells, es comprova l'existència de corrents continus en els punts mitjos dels condensadors que fan que els sistema sigui inestable. Es determinen gràficament les zones d'inestabilitat.
Es presenta un nou i eficient algorisme de modulació vectorial feedforward en el convertidor de tres nivells que és capaç de generar tensions trifàsiques de sortida equilibrades, malgrat l'existència de desequilibris en les tensions dels condensadors.
S'estudien els efectes negatius de càrregues lineals desequilibrades i càrregues no lineals en el control de les tensions dels condensadors. Es justifica que l'existència d'un quart harmònic en els corrents de càrrega pot inestabilitzar el sistema. És determina la màxima amplitud tolerable d'aquest harmònic.
S'estudia la millora en l'equilibrat de les tensions d'una connexió de dos convertidors de tres nivells al mateix bus de continua (back-to-back connection). Un exemple d'aplicació pràctica és la conversió AC/DC/AC per a l'accionament de motors d'alterna treballant amb factor de potència unitari.
Finalment s'aplica un controlador òptim al convertidor de tres nivells treballant com a rectificador elevador (boost). El llaç de control LQR (Linear Quadratic Regulator) es simplifica donat que la tasca d'equilibrat de les tensions dels condensadors es dur a terme en el mateix modulador.
48
Adabi, Firouzjaee Jafar. "Remediation strategies of shaft and common mode voltages in adjustable speed drive systems." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/39293/1/Jafar_Adabi_Firouzjaeel_Thesis.pdf.
Full textAbstract:
AC motors are largely used in a wide range of modern systems, from household appliances to automated industry applications such as: ventilations systems, fans, pumps, conveyors and machine tool drives. Inverters are widely used in industrial and commercial applications due to the growing need for speed control in ASD systems. Fast switching transients and the common mode voltage, in interaction with parasitic capacitive couplings, may cause many unwanted problems in the ASD applications. These include shaft voltage and leakage currents.
One of the inherent characteristics of Pulse Width Modulation (PWM) techniques is the generation of the common mode voltage, which is defined as the voltage between the electrical neutral of the inverter output and the ground. Shaft voltage can cause bearing currents when it exceeds the amount of breakdown voltage level of the thin lubricant film between the inner and outer rings of the bearing. This phenomenon is the main reason for early bearing failures.
A rapid development in power switches technology has lead to a drastic decrement of switching rise and fall times. Because there is considerable capacitance between the stator windings and the frame, there can be a significant capacitive current (ground current escaping to earth through stray capacitors inside a motor) if the common mode voltage has high frequency components. This current leads to noises and Electromagnetic Interferences (EMI) issues in motor drive systems.
These problems have been dealt with using a variety of methods which have been reported in the literature. However, cost and maintenance issues have prevented these methods from being widely accepted. Extra cost or rating of the inverter switches is usually the price to pay for such approaches. Thus, the determination of cost-effective techniques for shaft and common mode voltage reduction in ASD systems, with the focus on the first step of the design process, is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1.
Electrical power generation from renewable energy sources, such as wind energy systems, has become a crucial issue because of environmental problems and a predicted future shortage of traditional energy sources. Thus, Chapter 2 focuses on the shaft voltage analysis of stator-fed induction generators (IG) and Doubly Fed Induction Generators DFIGs in wind turbine applications. This shaft voltage analysis includes: topologies, high frequency modelling, calculation and mitigation techniques. A back-to-back AC-DC-AC converter is investigated in terms of shaft voltage generation in a DFIG. Different topologies of LC filter placement are analysed in an effort to eliminate the shaft voltage.
Different capacitive couplings exist in the motor/generator structure and any change in design parameters affects the capacitive couplings. Thus, an appropriate design for AC motors should lead to the smallest possible shaft voltage. Calculation of the shaft voltage based on different capacitive couplings, and an investigation of the effects of different design parameters are discussed in Chapter 3. This is achieved through 2-D and 3-D finite element simulation and experimental analysis.
End-winding parameters of the motor are also effective factors in the calculation of the shaft voltage and have not been taken into account in previous reported studies. Calculation of the end-winding capacitances is rather complex because of the diversity of end winding shapes and the complexity of their geometry. A comprehensive analysis of these capacitances has been carried out with 3-D finite element simulations and experimental studies to determine their effective design parameters. These are documented in Chapter 4. Results of this analysis show that, by choosing appropriate design parameters, it is possible to decrease the shaft voltage and resultant bearing current in the primary stage of generator/motor design without using any additional active and passive filter-based techniques.
The common mode voltage is defined by a switching pattern and, by using the appropriate pattern; the common mode voltage level can be controlled. Therefore, any PWM pattern which eliminates or minimizes the common mode voltage will be an effective shaft voltage reduction technique. Thus, common mode voltage reduction of a three-phase AC motor supplied with a single-phase diode rectifier is the focus of Chapter 5. The proposed strategy is mainly based on proper utilization of the zero vectors.
Multilevel inverters are also used in ASD systems which have more voltage levels and switching states, and can provide more possibilities to reduce common mode voltage. A description of common mode voltage of multilevel inverters is investigated in Chapter 6.
Chapter 7 investigates the elimination techniques of the shaft voltage in a DFIG based on the methods presented in the literature by the use of simulation results. However, it could be shown that every solution to reduce the shaft voltage in DFIG systems has its own characteristics, and these have to be taken into account in determining the most effective strategy.
Calculation of the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions is discussed in Chapter 8. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.
49
Dlima, Kendrick M. "Conceptual Design of a South Pole Carrier Pigeon UAV." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2145.
Full textAbstract:
Currently, the South Pole has a large data problem. It is estimated that 1.2 TB of data is being produced every day, but less than 500 GB of that data is being uploaded via aging satellites to researchers in other parts of the world. This requires those at the South Pole to analyze the data and carefully select the parts to send, possibly missing out on vital scientific information. The South Pole Carrier Pigeon will look to bridge this data gap.
The Carrier Pigeon will be a small unmanned aerial vehicle that will carry a 30 TB solid-state hard drive from the South Pole to various destinations in the Southern Hemisphere, but it has been designed to y to Christchurch, New Zealand. This 87 lb. UAV will be able to y 3,650 nmi. up to 25,000 ft., using a 5.7 hp. engine. It will feature an de-icing system on the leading edge of its 8 ft. span wing to allow it to y through cold, moist climates. It will have a 39 in. long fuselage with a tail boom of 33 in.
The aircraft has been designed to be made out of composites, thus reducing both the weight of the aircraft as well as its drag. It has been designed to come apart in order to be shipped successfully to the South Pole. There, it will be assembled and launched via a custom pneumatic launcher. It will y autonomously to 15,000 ft. and cruise climb throughout the flight to 25,000 ft., before descending to its destination. There, it will be caught by a net restraint system, where the hard drive will be extracted. The Carrier Pigeon is truly a unique vehicle for its size, range, and robustness.
50
Rethinagiri, Santhosh Kumar. "Une approche système pour l'estimation de la consommation de puissance des plateformes MPSoC." Phd thesis, Université de Valenciennes et du Hainaut-Cambresis, 2013. http://tel.archives-ouvertes.fr/tel-00943272.
Full textAbstract:
Avec l'essor des nouvelles technologies d'intégration sur silicium submicroniques, la consommation de puissance dans les systèmes sur puce multiprocesseur (MPSoC) est devenue un facteur primordial au niveau du flot de conception. La prise en considération de ce facteur clé dés les premières phases de conception, joue un rôle primordial puisqu'elle permet d'augmenter la fiabilité des composants et de réduire le temps d'arrivée sur le marché du produit final. Dans cette thèse, nous proposons une méthodologie efficace pour l'estimation de la consommation de puissance des plateformes MPSoC. Cette méthodologie repose sur une combinaison d'une analyse fonctionnelle de la puissance (FLPA) pour l'obtention des modèles de consommation et d'une technique de simulation au niveau transactionnel (TLM) pour calculer la puissance de l'ensemble du système. Fondamentalement, FLPA est proposée pour modéliser le comportement des processeurs en terme de consommation afin d'obtenir des modèles paramétrés de haut niveau. Dans ce travail, FLPA est étendue pour mettre en place des modèles de puissance génériques pour les différentes parties du système (mémoire, logique reconfigurable, etc.). En outre, un environnement de simulation a été développé au niveau transactionnel afin d'évaluer avec précision les activités utilisées dans les modèles de consommation. La combinaison de ces deux parties conduit à une estimation de la puissance hybride qui donne un meilleur compromis entre la précision et la vitesse. La méthodologie proposée a plusieurs avantages: elle estime la consommation du système embarqué dans tous ses éléments et conduit à des estimations précises sans matériel coûteux et complexe. La méthodologie proposée est évolutive pour explorer des architectures complexes embarquées. Notre outil d'estimation de puissance au niveau du système PETS (Power Estimation Tool at System-level) est développé sur la base de la méthodologie proposée. L'efficacité de notre outil PETS en termes de précision et rapidité est validée par des architectures embarquées monoprocesseur et multiprocesseur conçues autour des plateformes OMAP (3530 et 5912) et FPGA Pro Xilinx Virtex II.