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1
Thakral, Garima. "Process-Voltage-Temperature Aware Nanoscale Circuit Optimization." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc67943/.
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Embedded systems which are targeted towards portable applications are required to have low power consumption because such portable devices are typically powered by batteries. During the memory accesses of such battery operated portable systems, including laptops, cell phones and other devices, a significant amount of power or energy is consumed which significantly affects the battery life. Therefore, efficient and leakage power saving cache designs are needed for longer operation of battery powered applications. Design engineers have limited control over many design parameters of the circuit and hence face many chal-lenges due to inherent process technology variations, particularly on static random access memory (SRAM) circuit design. As CMOS process technologies scale down deeper into the nanometer regime, the push for high performance and reliable systems becomes even more challenging. As a result, developing low-power designs while maintaining better performance of the circuit becomes a very difficult task. Furthermore, a major need for accurate analysis and optimization of various forms of total power dissipation and performance in nanoscale CMOS technologies, particularly in SRAMs, is another critical issue to be considered. This dissertation proposes power-leakage and static noise margin (SNM) analysis and methodologies to achieve optimized static random access memories (SRAMs). Alternate topologies of SRAMs, mainly a 7-transistor SRAM, are taken as a case study throughout this dissertation. The optimized cache designs are process-voltage-temperature (PVT) tolerant and consider individual cells as well as memory arrays.
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Rosehart, William D. "Optimization of power systems with voltage security constraints." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60563.pdf.
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Pereira, Pedro Miguel Ribeiro. "Optimization based design of LC voltage controlled oscilators." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11349.
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Chiang, Meei-Ling. "Design and optimization of low-voltage switched-capacitor systems /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/5918.
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Ziari, Iman. "Planning of distribution networks for medium voltage and low voltage." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/46684/1/Iman_Ziari_Thesis.pdf.
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Determination of the placement and rating of transformers and feeders are the main objective of the basic distribution network planning. The bus voltage and the feeder current are two constraints which should be maintained within their standard range. The distribution network planning is hardened when the planning area is located far from the sources of power generation and the infrastructure. This is mainly as a consequence of the voltage drop, line loss and system reliability. Long distance to supply loads causes a significant amount of voltage drop across the distribution lines. Capacitors and Voltage Regulators (VRs) can be installed to decrease the voltage drop. This long distance also increases the probability of occurrence of a failure. This high probability leads the network reliability to be low. Cross-Connections (CC) and Distributed Generators (DGs) are devices which can be employed for improving system reliability. Another main factor which should be considered in planning of distribution networks (in both rural and urban areas) is load growth. For supporting this factor, transformers and feeders are conventionally upgraded which applies a large cost. Installation of DGs and capacitors in a distribution network can alleviate this issue while the other benefits are gained.
In this research, a comprehensive planning is presented for the distribution networks. Since the distribution network is composed of low and medium voltage networks, both are included in this procedure. However, the main focus of this research is on the medium voltage network planning. The main objective is to minimize the investment cost, the line loss, and the reliability indices for a study timeframe and to support load growth. The investment cost is related to the distribution network elements such as the transformers, feeders, capacitors, VRs, CCs, and DGs. The voltage drop and the feeder current as the constraints are maintained within their standard range.
In addition to minimizing the reliability and line loss costs, the planned network should support a continual growth of loads, which is an essential concern in planning distribution networks. In this thesis, a novel segmentation-based strategy is proposed for including this factor. Using this strategy, the computation time is significantly reduced compared with the exhaustive search method as the accuracy is still acceptable. In addition to being applicable for considering the load growth, this strategy is appropriate for inclusion of practical load characteristic (dynamic), as demonstrated in this thesis.
The allocation and sizing problem has a discrete nature with several local minima. This highlights the importance of selecting a proper optimization method. Modified discrete particle swarm optimization as a heuristic method is introduced in this research to solve this complex planning problem. Discrete nonlinear programming and genetic algorithm as an analytical and a heuristic method respectively are also applied to this problem to evaluate the proposed optimization method.
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Okubo, H., T. Otsuka, K. Kato, N. Hayakawa, and M. Hikita. "Electric field optimization of high voltage electrode based on neural network." IEEE, 1997. http://hdl.handle.net/2237/6881.
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Westerberg, Jens. "Optimering av ett mellanspänningsnät : Optimization of a medium voltage electricity grid." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-104889.
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EU vill genom att använda energin effektivare sänka sina energikostnader och minska sitt beroende av externa leverantörer av olja och gas vilket leder till att miljön skyddas. Av den anledningen krävs att energieffektiviteten ökas från produktion till den slutgiltiga konsumtionen inom EU. Jämtkraft är miljöcertifierat enligt ISO 14001 och arbetar därför årligen mot uppsatta miljömål. Detta examensarbete har studerat ett av dessa mål, möjligheten att minska överföringsförluster i ett av Jämtkrafts mellanspänningsnät. Området som examensarbetet baseras på är fördelningsstation Nälden FS23. Denna studie har undersökt möjligheterna att minska överföringsförluster i sex utgående linjer, från fördelningsstation till kunderna. Denna studie visar att det finns potential att minska överföringsförluster genom att öka spänningen i nätet. En direkt åtgärd och en långsiktig åtgärd har presenterats med olika potential. Den direkta åtgärden gör det möjligt att minska de årliga överföringsförlusterna med 6 MWh och det långsiktiga alternativet gör det möjligt att minska de årliga överföringsförlusterna i det studerade området med 14 MWh.<br>EU wants to reduce their energy costs and reduce its dependence on external suppliers of oil and gas by using energy more efficiently which leads to protection of the environment. For that reason it is crucial that energy efficiency is increased from production to final consumption in the EU. Jämtkraft is environmentally certified according to ISO 14001 and are therefore working yearly on environmental goals. This degree project has studied one of those goals, the opportunity to reduce transmission losses in one of Jämtkrafts medium voltage electricity grid. The area which this degree project is based on is the distribution station Nälden FS23. This study has examined the possibilities of decreasing transmission losses in six outgoing lines, from distribution station to customers. This study shows that there is potential to reduce transmission losses by increasing the voltage in the grid. A direct action as well as a long-term action was presented with different potential. A direct action makes it possible to reduce yearly transmission losses by 6 MWh and the long-term alternative makes it possible to reduce the yearly transmission losses in the studied area by 14 MWh
8
Panji, Arikson Heraldus. "Optimization of High Voltage Cable Dimension in Scania Electric Vehicle’s Systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278073.
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With the increasing demand for electrified vehicles, the demand for electrical components, including cables, is rising too. Thus, it is important to develop a method to optimize the cable sizing to ensure the cable is technically robust and economically efficient. The aim of this project is to study and evaluate different cables’ designs to find the optimum dimension for “high voltage” class (automotive voltage class B) cables in the electrical vehicle system. Three important technical aspects in evaluating the optimum cross-section area (CSA) are the ampacity of the cable, short-circuit withstand capability and voltage drop.In this project, the ampacity of a cable placed in air is calculated by the analytical method based on IEC 60287 and by a finite-element simulation. These results are verified against direct measurements using a dc source and load. In DC calculation, the similarity of all three methods is high, within 96%. The formation of the cable also affects the ampacity of the cable. For DC currents, the vertical formation has a higher ampacity than the horizontal formation, by almost 2%. For AC currents, the trefoil formation has a higher ampacity than the horizontal and vertical formation, by around 6-9%.Calculations of short circuit withstand capability and voltage drop were performed to ensure cable performance. The larger CSA corresponds to both higher short circuit capability and lower voltage drop. In a short circuit, a duration around 0.5 s is critical since there is a significant difference between short circuit withstand capability before and after this. Voltage drop calculation is performed to ensure that the combination of CSA and length does not exceed 3% voltage drop at the load end side of the circuit. The Voltage drop is not found to be an important factor to consider. Based on those three factors, the optimization process is described with a flowchart.<br>Efterfrågan på elfordon ökar, och därmed ökar också efterfrågan på den elektriska komponenten. Därför är det viktigt att utveckla en metod för att optimera kabelstorleken så att kabeln är tekniskt robust och ekonomiskt effektiv. Syftet med detta projekt är att studera och utvärdera olika kablarnas konstruktioner för att hitta den optimala dimensionen för högspänningsklass (spänningsklass B) i elfordonssystemet. Tre viktiga tekniska aspekter vid utvärderingen av den optimala kabelstorleken är kabelns kapacitet, kortslutningsförmåga och spänningsfall.I detta projekt placeras kabeln i luften. Ampaciteten beräknas med hjälp av en analytisk metod baserad på IEC 60287 och en simulering med finita element metoden. Dessa resultat verifieras mot direkta mätningar med hjälp av en likströmskälla och elektrisk belastning. För DC-beräkning är likheten för alla tre metoderna mycket hög. Bildningen av kabeln påverkar också kabelns ampacitet. För DC-strömmar har den vertikala formationen en högre ampacitet än den horisontella formationen för nästan 2%. För växelströmmar har trefoilformationen en högre ampacitet än den horisontella och vertikala formationen med 6-9 %.Kortslutningsförmågan och spänningsfallberäkningen utfördes för att säkerställa kabelprestanda. En större CSA innebär högre kortslutningsförmåga och lägre spänningsfall. Spänningsfallberäkning utförs för att begränsa kabellängden för att säkerställa ett maximalt 3% spänningsfall vid kretsens laständsida. Spänningsfallet är en viktig faktor att beakta. Med hjälp av dessa tre faktorer beskrivs optimeringsprocessen med ett flödesschema.
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Mijatovic, Aaron. "Solving optimal power flow with voltage constraints using MATLAB optimization toolbox." Thesis, Mijatovic, Aaron (2013) Solving optimal power flow with voltage constraints using MATLAB optimization toolbox. Other thesis, Murdoch University, 2013. https://researchrepository.murdoch.edu.au/id/eprint/21660/.
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This thesis set out to build a program in MATLAB that is designed to find an optimal power flow system on that minimizes the cost of generation while satisfying prescribed voltage constraints.
Current optimal power flow solutions generally have three main issues with optimal power flow and this is the direction of most research in the area. The first issue is that the systems are not able to robustly provide a solution to the given information and are unable to find a stable solution. The second issue is that the optimal power flow may only find a local minimum solution rather than a global minimum due to the nature of the optimization routines. The third and final issue is that the solve time needs to be kept to a minimum to ensure usability in real world systems.
The system was built in MATLAB using the Optimization Toolbox, and specifically the fmincon function. The system accepted some basic input variables including a formatted numerical description of the power network, and then performed some calculations to prepare the system for solving. The system was then solved according to Economic Dispatch which determined that the sum of generation should equal the sum of the load. Losses were ignored and new starting variables for the generators where determined. These starting variables were passed into a Gauss-Seidel iterative method which solved the new bus voltages and reactive generation for each of the generators. The objective function for fmincon was set to minimise the cost of the generators, and the constraint function was set to the Gauss-Seidel iteration. Buses were given lower and upper constraints and generator constraints were set from the minimum and maximum given in initialization. Fmincon was then called and solved for minimum cost according to stable constraints.
The system was able to solve this problem the optimal power flow and provide an appropriate solution. However it was not determined whether the solution was a global minimum, or simply a local one. Stability was determined by the generators and buses being within their limits and a voltage stability index was determined. Different starting positions determined that using the economic dispatch provided the cheapest solution and produced a stable outcome.
This thesis provides strong starting point for further expansion into the field of optimal power flow. The program provides a solution and is set to certain stability constraints. Adding new constraints, or increasing the size of the system is easily possible by the user.
10
Jalali, Mana. "Voltage Regulation of Smart Grids using Machine Learning Tools." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/95962.
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Smart inverters have been considered the primary fast solution for voltage regulation in power distribution systems. Optimizing the coordination between inverters can be computationally challenging. Reactive power control using fixed local rules have been shown to be subpar. Here, nonlinear inverter control rules are proposed by leveraging machine learning tools. The designed control rules can be expressed by a set of coefficients. These control rules can be nonlinear functions of both remote and local inputs. The proposed control rules are designed to jointly minimize the voltage deviation across buses. By using the support vector machines, control rules with sparse representations are obtained which decrease the communication between the operator and the inverters. The designed control rules are tested under different grid conditions and compared with other reactive power control schemes. The results show promising performance.<br>With advent of renewable energies into the power systems, innovative and automatic monitoring and control techniques are required. More specifically, voltage regulation for distribution grids with solar generation is a can be a challenging task. Moreover, due to frequency and intensity of the voltage changes, traditional utility-owned voltage regulation equipment are not useful in long term. On the other hand, smart inverters installed with solar panels can be used for regulating the voltage. Smart inverters can be programmed to inject or absorb reactive power which directly influences the voltage. Utility can monitor, control and sync the inverters across the grid to maintain the voltage within the desired limits. Machine learning and optimization techniques can be applied for automation of voltage regulation in smart grids using the smart inverters installed with solar panels. In this work, voltage regulation is addressed by reactive power control.
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Choi, Kyu-Won. "Hierarchical power optimization for ultra low-power digital systems." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180111/unrestricted/choi%5Fkyu-won%5F200312%5Fphd.pdf.
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Steiger, DeAnna Lee Borchardt. "Optimization and use of a voltage clamp assay with insect midgut tissues." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.38 Mb., 53 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435810.
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Bilgili, Hulusi Birol. "Pressure, Gas Ratio And Operation Voltage Optimization Of A Helium-neon Laser." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12605917/index.pdf.
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Aim of this thesis is to investigate the optimum working parameters of a helium-neon laser. Partial pressure ratios, total pressures of the gases and voltage-current characteristics were studied. The analysis of the results includes the minor factors (impurity, volume, etc.) and their effects to main parameters (laser power, voltage, current). Tables, which were formed by measured optical parameters as wavelength and power, converted to graphs and from these graphs optimal working conditions for the laser are obtained.
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Kalyani, Radha Padma. "A nonlinear optimization approach for UPFC power flow control and voltage security." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Kalyani_completeThesis_09007dcc80438f59.pdf.
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Thesis (Ph. D.)--University of Missouri--Rolla, 2007.<br>Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 29, 2007) Includes bibliographical references.
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Majzoub, Sohaib. "Energy optimization for many-core platforms under process, voltage and temperature variations." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27902.
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Many-core architectures are the most recent shift in multi-processor design. This processor design paradigm replaces large monolithic processing units by thousands of simple processing elements on a single chip. With such a large number of processing units, it promises significant throughput advantage over traditional multi-core platforms. Furthermore, it enables better localized control of power consumption and thermal gradients. This is achieved by selective reduction of the core’s supply voltage, or by switching some of the cores off to reduce power consumption and heat dissipation.
This dissertation proposes an energy optimization flow to implement applications on many-core architectures taking into account the impact of Process Voltage and Temperature (PVT) variations. The flow utilizes multi-supply voltage techniques, namely voltage island design, to reduce power consumption in the implementation. We propose a novel approach to voltage island formation, called Voltage Island Clouds, that reduces the impact of on-chip or intra-die PVT variations. The islands are created by balancing their shape constraints imposed by intra- and inter-island communication with the desire to limit the spatial extent of each island to minimize PVT impact. We propose an algorithm to build islands for Static Voltage Scaling (SVS) and Multiple Voltage Scaling (MVS) design approaches.
The optimization initially allows for a large number of islands, each with its unique voltage level. Next, the number of the islands is reduced to a small practical number, e.g., four voltages. We then propose an efficient voltage selection approach, called the Removal Cost Method (RCM), that provides near optimal results with more than a 10X speedup compared to the best-known previous methods. Finally, we present an evaluation platform considering pre- and post-fabrication PVT scenarios where multiple applications with hundreds to thousands of tasks are mapped onto many-core platforms with hundreds to thousands of cores to evaluate the proposed techniques. Results show that the geometric average energy savings for 33 test cases using the proposed methods is 25% better than previous methods.
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Islas, Michael. "EFFICIENCY IMPROVEMENT TECHNIQUES FOR HIGH VOLTAGE CAPACITOR CHARGING METHODS." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2969.
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The goal of this thesis is to design and fabricate a DC-to-DC converter for use in high-voltage capacitor charging applications. The primary objectives include increasing the efficiency and reducing the cost of traditional methods used for this application. Traditional methods were not designed specifically for high-voltage capacitor charging and were thus very primitive and exhibited lower efficiency. Prior methods made use of a high voltage power supply and a current limiting resistor or control scheme. The power supply would often only operate efficiently at a single voltage value and would thus function poorly over a range used in charging a capacitor. The resistor would also dissipate a fair amount of power, also limiting efficiency. This design makes use of a traditional flyback topology utilizing a controller developed specifically for this application, centering the design approach on the LT3750. Hence, taking full advantage of the efficiency improving control scheme it provides. Additionally, through the use of advanced techniques to eliminate noise and power losses, the efficiency may be significantly improved. A detailed theoretical analysis of the charger is also presented. The analysis will then be applied to optimization techniques to select ideal component values to meet specific design specifications. In this research, a specifically designed and developed prototype will be used to experimentally verify the theoretical work and optimization techniques.<br>M.S.E.E.<br>School of Electrical Engineering and Computer Science<br>Engineering and Computer Science<br>Electrical Engineering MSEE
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Amarchinta, Sumanth. "High performance subthreshold standard cell design and cell placement optimization /." Online version of thesis, 2009. http://hdl.handle.net/1850/10740.
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Song, Yang. "Design of secondary voltage and stability controls with multiple control objectives." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29714.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Begovic, Miroslav; Committee Member: Deng, Shijie; Committee Member: Divan, Deepakraj; Committee Member: Harley, Ronald; Committee Member: Lambert, Frank; Committee Member: Shamma, Jeff. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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GREENHALGH, ANGELA BARBOSA. "VOLTAGE STABILITY ENHANCEMENT IN THE OPERATION OF POWER SYSTEMS THROUGH AN OPTIMIZATION MODEL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8943@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>Muito tem sido feito para que se possa entender os
mecanismos que levam o sistema a uma situação de
instabilidade de tensão e até mesmo ao colapso, assim como
também para se suprir a necessidade de ferramentas
analíticas capazes de prever e avaliar a proximidade do
colapso de tensão em sistemas complexos, identificando as
áreas susceptíveis à instabilidade de tensão.
Uma vez detectada a inconveniente proximidade a uma
condição de operação susceptível ao colapso de tensão, é
necessária a identificação de grandezas-chave e
sensibilidades, que forneçam entendimento suficiente, para
ajudar no desenvolvimento de metodologias para reforçar as
condições de estabilidade de tensão. Tendo isto como
objetivo, este trabalho trata do problema de reforço da
estabilidade de tensão através da mudança do perfil de
tensão, utilizando como ferramenta computacional um
algoritmo de otimização.
Há no sistema variáveis de controle que interferem
diretamente no perfil de tensão, tais como, tensão base
nos geradores e compensadores, taps de transformadores, e
capacitadores e reatores usados para compensação de
potência reativa. Entretanto, quando as condições de
estabilidade já se encontram deterioradas, as ações de
controle do perfil de tensão podem levar a resultados
insatisfatórios, podendo mesmo agravar o problema.
Neste trabalho é apresentada uma metodologia, baseada em
algoritmo de otimização, que fornece a lista de variáveis
de controle mais eficientes para o reforço da estabilidade
de tensão, e a direção em que os controles devem ser
acionados. O interesse é obter um ponto de operação viável
mais robusto, do ponto de vista de estabilidade de tensão,
e não necessariamente um ponto de operação ótimo.<br>Much hás been done for the understanding of the voltage
instabilitu mechanisms and to supply the necessity of
analytical tools, which should have the ability tom
predict and evaluate the proximity of voltage collapse in
complex systems, identifying the critical áreas
susceptible to voltage istability.
Once the inconvenient proximity to an operating condition
susceptible to voltage collapse is identified, it is
necessary to look for the key factors and sensitivities
that provide the reinforcement of the voltage stability
conditions. Having it as a goal, this work treats the
problem of reinforcing the voltage stability conditions,
through changes of the voltage profile, using an optimal
algorithm as a computational tool.
There are control variables in the system which directly
interfere on the voltage profile, such as, voltage set
point on generators and compensators, transformer taps,
capacitors and reactors. However, when the voltage
stability conditions are already deteriorated, the voltage
profile control actions may lead to unsatisfactory
results, and may even aggravate the problem.
It is presented a methodology based on an optimal, that
provides the list of the most efficient control variables
for the reinforcement of voltage stability, and the
corresponding direction of movement. The search is for a
feasible operating point, more robust in relation to
voltage stability, and not necessarily for an optimal
operating point.
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Zelinskyi, S. A., Y. A. Maletin, N. G. Stryzhakova, S. A. Tychyna, and D. M. Drobny. "Electrochemical Behavior of Carbon Electrodes as a Key to Supercapacitor Optimization." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35501.
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The paper describes the electrochemical behavior of supercapacitor electrodes in both positive and negative
ranges. This study has become possible due to development of a special reference electrode, which is
stable in aprotic electrolytes like, e.g., 1.3 M Et3MeNBF4 in acetonitrile. Three-electrode measurements
have enabled us to find the boundary potentials for various nanoporous carbon materials to be then used in
the supercapacitor technology. This article describes how the electrode size can be optimized to get the
maximum charge value in the double electric layer at the electrode-electrolyte interface. Besides, we illustrate
how the supercapacitor rated voltage can be increased up to 2.9 V as compared with the typical value
of 2.7 V. This provides the 15 % increase in energy and power.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35501
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Wang, Zhaoyu. "Implementation and assessment of demand response and voltage/var control with distributed generators." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53928.
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The main topic of this research is the efficient operation of a modernized distribution grid from both the customer side and utility side. For the customer side, this dissertation discusses the planning and operation of a customer with multiple demand response programs, energy storage systems and distributed generators; for the utility side, this dissertation addresses the implementation and assessment of voltage/VAR control and conservation voltage reduction in a distribution grid with distributed generators.
The objectives of this research are as follows: (1) to develop methods to assist customers to select appropriate demand response programs considering the integration of energy storage systems and DGs, and perform corresponding energy management including dispatches of loads, energy storage systems, and DGs; (2) to develop stochastic voltage/VAR control techniques for distribution grids with renewable DGs; (3) to develop optimization and validation methods for the planning of integration of renewable DGs to assist the implementation of voltage/VAR control; and (4) to develop techniques to assess load-reduction effects of voltage/VAR control and conservation voltage reduction.
In this dissertation, a two-stage co-optimization method for the planning and energy management of a customer with demand response programs is proposed. The first level is to optimally select suitable demand response programs to join and integrate batteries, and the second level is to schedule the dispatches of loads, batteries and fossil-fired backup generators. The proposed method considers various demand response programs, demand scenarios and customer types. It can provide guidance to a customer to make the most beneficial decisions in an electricity market with multiple demand response programs.
For the implementation of voltage/VAR control, this dissertation proposes a stochastic rolling horizon optimization-based method to conduct optimal dispatches of voltage/VAR control devices such as on-load tap changers and capacitor banks. The uncertainties of renewable DG output are taken into account by the stochastic formulation and the generated scenarios. The exponential load models are applied to capture the load behaviors of various types of customers.
A new method to simultaneously consider the integration of DGs and the implementation of voltage/VAR control is also developed. The proposed method includes both solution and validation stages. The planning problem is formulated as a bi-level stochastic program. The solution stage is based on sample average approximation (SAA), and the validation stage is based on multiple replication procedure (MRP) to test the robustness of the sample average approximation solutions of the stochastic program.
This research applies big data-driven analytics and load modeling techniques to propose two novel methodologies to assess the load-reduction effects of conservation voltage reduction. The proposed methods can be used to assist utilities to select preferable feeders to implement conservation voltage reduction.
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Ibrahim, Sarmad Khaleel. "DISTRIBUTION SYSTEM OPTIMIZATION WITH INTEGRATED DISTRIBUTED GENERATION." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/116.
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In this dissertation, several volt-var optimization methods have been proposed to improve the expected performance of the distribution system using distributed renewable energy sources and conventional volt-var control equipment: photovoltaic inverter reactive power control for chance-constrained distribution system performance optimisation, integrated distribution system optimization using a chance-constrained formulation, integrated control of distribution system equipment and distributed generation inverters, and coordination of PV inverters and voltage regulators considering generation correlation and voltage quality constraints for loss minimization. Distributed generation sources (DGs) have important benefits, including the use of renewable resources, increased customer participation, and decreased losses. However, as the penetration level of DGs increases, the technical challenges of integrating these resources into the power system increase as well. One such challenge is the rapid variation of voltages along distribution feeders in response to DG output fluctuations, and the traditional volt-var control equipment and inverter-based DG can be used to address this challenge.
These methods aim to achieve an optimal expected performance with respect to the figure of merit of interest to the distribution system operator while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections. The first method is used to optimize only the reactive power output of DGs to improve system performance (e.g., operating profit) and compensate for variations in active power injection while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections over the interval of interest. The second method proposes an integrated volt-var control based on a control action ahead of time to find the optimal voltage regulation tap settings and inverter reactive control parameters to improve the expected system performance (e.g., operating profit) while keeping the voltages across the system within specified ranges and considering the uncertainty of DG power injections over the interval of interest. In the third method, an integrated control strategy is formulated for the coordinated control of both distribution system equipment and inverter-based DG. This control strategy combines the use of inverter reactive power capability with the operation of voltage regulators to improve the expected value of the desired figure of merit (e.g., system losses) while maintaining appropriate system voltage magnitudes. The fourth method proposes a coordinated control strategy of voltage and reactive power control equipment to improve the expected system performance (e.g., system losses and voltage profiles) while considering the spatial correlation among the DGs and keeping voltage magnitudes within permissible limits, by formulating chance constraints on the voltage magnitude and considering the uncertainty of PV power injections over the interval of interest.
The proposed methods require infrequent communication with the distribution system operator and base their decisions on short-term forecasts (i.e., the first and second methods) and long-term forecasts (i.e., the third and fourth methods). The proposed methods achieve the best set of control actions for all voltage and reactive power control equipment to improve the expected value of the figure of merit proposed in this dissertation without violating any of the operating constraints. The proposed methods are validated using the IEEE 123-node radial distribution test feeder.
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Ye, Hanyu [Verfasser]. "Application of Non-Linear Microvaristor-Filled Materials in High-Voltage Devices and Algorithmic Optimization of High-Voltage Simulations Based on Surrogate Models / Hanyu Ye." Wuppertal : Universitätsbibliothek Wuppertal, 2015. http://d-nb.info/1071414860/34.
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Hung, Wei-Chen. "On-line Thermal Aware Energy Optimization via Dynamic Voltage Selection for Multiprocessor System-On-Chip." Thesis, Linköpings universitet, ESLAB - Laboratoriet för inbyggda system, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-65742.
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In recent decades, the use of electronic systems, especially embedded systems such as mobile phones has been expanding rapidly. Such products use minimal amount of materials, generate less waste and noise, save space, and are considered cost-effective and attractive. In such devices, consideration needs to be given to both high power density and high chip working temperature. According to the advanced scaling technology, leakage power becomes a major issue in terms of power consumption and this in turn influences temperature. Consequently, energy optimization is an important issue in the design of such electronic products. Techniques for energy optimization have been proposed for circuit-level up to the system-level. This study is focused on a system-level model for a multiprocessor system, considering the inter-dependency between leakage power and temperature. The study applies an on-line temperature-aware dynamic voltage selection (DVS) approach to save energy. The method is evaluated and compared to the static approach, which assumes that tasks always execute their worst case number of clock cycles (WNC) allowing for the exploitation of only the static slack. On-line thermal aware DVS allows the exploitation of both the static and dynamic slacks, since the actual number of clock cycles is usually less than the WNC.
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Terrin, Massimo. "Micro-CT for small animal imaging : Optimization of the tube voltage for low-contrast imaging." Thesis, KTH, Skolan för teknik och hälsa (STH), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176482.
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This master thesis evaluated the optimal tube voltage for low-contrast imaging of a micro-CT system (intended for small animal imaging) built at the School of Technology and Health (STH) of the Royal Institute of Technology (KTH). The main goal of this work was to calibrate the above-mentioned device (composed moreover by a Hamamatsu microfocus L10951-01 X-ray tube, a CMOS flat panel Hamamatsu C7942CA-22 and using a Cone-Beam CT reconstruction algorithm) for obtaining the best imaging of low-contrast structures. In order to do this, an analytical model, re-adapted from the previous state-of-the-art Micro-CT studies, was evaluated for finding a sub-optimal tube voltage from which to start the experiments, done on a reference Low-Contrast phantom specifically intended for the calibration of Micro-CT devices. Finally, by looking to the results from the experiments, a good tube setting for the optimization of the CT for low-contrast imaging was found. The optimal tube voltage for low-contrast imaging, from the experiments on the QRM phantom, was found to be between 48 and 50 kV. This tube voltage values gave the best CNR and contrast profiles results. Ultimately, we found that the usage of a 1mm Al filtration reduced the absorbed dose without affecting the image quality.
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Svilan, Vjekoslav. "Analysis, optimization, and modeling of CMOS circuits incorporating variable supply voltage and adaptive body bias /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Osgood, Karina, Larry Burke, Amy Webb, John Muir, Christina Dearstine, and Anthony Quaglietta. "OPTIMIZATION OF A MINATURE TRANSMITTER MODULE FOR WIRELESS TELEMETRY APPLICATIONS." International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/606385.
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International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California<br>M/A-COM, Inc. has previously developed a highly integrated transmitter chip set for wireless telemetry
applications for the military L and S band frequencies and the commercial 2.4GHz ISM band. The original
chip set is comprised of a voltage controlled oscillator (VCO), a silicon phase locked loop (PLL), and a
family of power amplifiers (PA's). Using these components, M/A-COM has produced a miniature IRIG-compliant
transmitter module, which has been flight-tested by the U.S. Army’s Hardened Subminiature
Telemetry and Sensor System (HSTSS) program. Since the initial offering, several product enhancements
have been added. The module performance has been improved by tailoring the VCO specifically for direct
frequency modulation applications. In addition to improving noise performance, these enhancements have
produced improved modulation linearity, decreased lock time and increased carrier stability. Modulation
rates in excess of 10Mbps have been demonstrated. High efficiency power amplifiers operating at 3V have
also been added to the family of amplifiers (PAE > 50%). This greatly enhanced efficiency allows higher RF
power output while maintaining the same miniature form factor for the transmitter. Further, M/A-COM has
added a silicon-on-sapphire PLL to the chip set, which operates at frequencies up to 3.0GHz. This paper
details the enhancements to the components within the chip set, and the improvement in performance of the
transmitter module. Test data is presented for the transmitter modules and individual components.
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Liang, Wen-Ting. "Optimal Planning of the Distribution Network with Distributed Generation." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15526.
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The deregulation of electricity market created a competitive market environment. For Distribution companies (DISCOs), how to maximize its profit is the primary purpose of this planning and operations. Therefore, to achieve the best economic and technical benefits, a DISCOs should determine where and how much DG units allow to install in the system. Distributed generation is a key component in the power market. There is a brief introduction of DG in this thesis including: the definition of DG, size and several often used DG types. The benefit and risk of DG which may bring to the power system also have been appropriately evaluated in this study. The review of literature of optimal size and location of DG in distribution system have shown that a number of economic and technical impacts have been considered in DG planning. The selection of the best places and the preferable size of DG units for installation in the distribution system is a complex combinatorial optimization problem. The various solution techniques along with various objective function and constraints for the optimal solution of the problem of size and location problem of DG are discussed and compared in this work. With the increasing of load demand, distributed generation becomes an attractive alternative method to supply the power in the distribution system. DG can not only help to defer the T&D investment but also bring benefits to environment protection. The technical benefit which can bring to the distribution system also cannot be ignored. Such as power loss reduction, voltage profile and power quality improvement. The impact of DG units on voltage stability has become significant. A review of the indices refers to voltage stability has been shown in this work and an index named voltage collapse proximity index (VCPI) was introduced and used in this work. This study proposed a planning framework for effective planning of DG units in the distribution system due to minimize total cost and enhance the voltage stability of the system. To achieve the purpose of minimizing the total cost and maximize the technical benefit of DG units to voltage stability, a multi-objective methodology to decide optimal locations and size of DG units. The total cost in the proposed planning model includes investment cost, operation and maintenance cost except the revenue from the utility grid. VCPI which is given in this study have been used in this model to identify the voltage stability of this system. The uncertainties associated with the load value, and generated power of renewable energy DG units also take a part in this study. A Monte Carlo simulation method has been introduced in this work to calculate the uncertainty because of probabilistic nature of renewable DG unit (WTs, PVs). The Pareto optimal set is found by using non-dominated sorting genetic algorithm method and the final result is chosen by using the max-min method. An IEEE 33-bus distribution system with DG installation has been used to achieve the goals of minimum total cost and improvement of voltage stability.
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Constante, Flores Gonzalo Esteban. "Conservation Voltage Reduction of Active Distribution Systems with Networked Microgrids." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531861356445195.
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Lindén, Annica, and Anna Ågren. "Load flow control and optimization of Banverket’s 132 kV 16 2/3 Hz high voltage grid." Thesis, Linköping University, Department of Electrical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4583.
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<p>The purpose of this thesis was to investigate the possibility of power flow control, on a section of a railway grid fed by rotary converters, using an extra feeding line. Two possible solutions for the power flow control were examined. The first using a series reactance in connection to each converter station and the second by changing the tap changer level of the transformer between the converter station and the feeding line.</p><p>In the two models a distance, comparable to the distance between Boden and Häggvik, in Stockholm, was used. The simulations were performed using the software SIMPOW.</p><p>The results from the performed simulations show that series reactances, under the stated conditions, can essentially improve the power flow. To implement this air coils with inductances in the approximate size of 10 to 45 mH could be used. Further, the tap changer levels of the transformer may be used, for individual converter stations, as a way to control the reactive power flow.</p>
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Okubo, Hitoshi, Fumihiro Endo, Naoki Hayakawa, Hiroki Kojima, and Yotaro Suzuki. "Optimization of Asset Management in High Voltage Substation Based on Equipment Monitoring and Power System Operation." IEEE, 2010. http://hdl.handle.net/2237/14536.
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Hannisdal, Erik Lundegaard. "Optimal Voltage Control of the Southern Norwegian Power Grid : Mixed Integer Nonlinear Programming (MINLP) for Control and Optimization of the High Voltage Southern Norwegian Power Grid." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13180.
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This thesis contains the synthesis, analysis and simulation results of an automatic optimal voltage controller for the Southern Norwegian power grid. Currently the high voltage power grid is controlled manually by operators switching control components. The optimal controller handles the voltage control of the system, as well as keeping the number of control actions to a minimum.The system model is derived from power system analysis. Due to a highy nonlinear system model and integer decission variables in on/off control components, the controller is based on mixed integer nonlinear programming (MINLP). The MINLP uses BONMIN as a solver, and is implemented with the AMPL programming language.It was found that a MINLP controller is good choice for voltage control in transmission systems. The controller handles voltage limits, as well as reducing the number of control actions.The thesis also contains comparison between different solution methods for applying the optimal voltage controller, as well as other approaches to the automatic voltage control problem.
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Elahipanah, Hossein. "Design Optimization and Realization of 4H-SiC Bipolar Junction Transistors." Doctoral thesis, KTH, Elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211659.
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4H-SiC-based bipolar junction transistors (BJTs) are attractive devices for high-voltage and high-temperature operations due to their high current capability, low specific on-resistance, and process simplicity. To extend the potential of SiC BJTs to power electronic industrial applications, it is essential to realize high-efficient devices with high-current and low-loss by a reliable and wafer-scale fabrication process. In this thesis, we focus on the improvement of the 4H-SiC BJT performance, including the device optimization and process development. To optimize the 4H-SiC BJT design, a comprehensive study in terms of cell geometries, device scaling, and device layout is performed. The hexagon-cell geometry shows 42% higher current density and 21% lower specific on-resistance at a given maximum current gain compared to the interdigitated finger design. Also, a layout design, called intertwined, is used for 100% usage of the conducting area. A higher current is achieved by saving the inactive portion of the conducting area. Different multi-step etched edge termination techniques with an efficiency of >92% are realized. Regarding the process development, an improved surface passivation is used to reduce the surface recombination and improve the maximum current gain of 4H-SiC BJTs. Moreover, wafer-scale lift-off-free processes for the n- and p-Ohmic contact technologies to 4H-SiC are successfully developed. Both Ohmic metal technologies are based on a self-aligned Ni-silicide (Ni-SALICIDE) process. Regarding the device characterization, a maximum current gain of 40, a specific on-resistance of 20 mΩ·cm2, and a maximum breakdown voltage of 5.85 kV for the 4H-SiC BJTs are measured. By employing the enhanced surface passivation, a maximum current gain of 139 and a specific on-resistance of 579 mΩ·cm2 at the current density of 89 A/cm2 for the 15-kV class BJTs are obtained. Moreover, low-voltage 4H-SiC lateral BJTs and Darlington pair with output current of 1−15 A for high-temperature operations up to 500 °C were fabricated. This thesis focuses on the improvement of the 4H-SiC BJT performance in terms of the device optimization and process development for high-voltage and high-temperature applications. The epilayer design and the device structure and topology are optimized to realize high-efficient BJTs. Also, wafer-scale fabrication process steps are developed to enable realization of high-current devices for the real applications.<br><p>QC 20170810</p>
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Pujary, Chirag Jayakar. "Investigation of Photodetector Optimization in Reducing Power Consumption by a Noninvasive Pulse Oximeter Sensor." Digital WPI, 2004. https://digitalcommons.wpi.edu/etd-theses/108.
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Noninvasive pulse oximetry represents an area of potential interest to the army, because it could provide cost-effective, safe, fast and real-time physiological assessment in a combat injured soldier. Consequently, there is a need to develop a reliable, battery-powered, wearable pulse oximeter to acquire and process photoplethysmographic (PPG) signals using an optimized sensor configuration. A key requirement in the optimal design of a wearable wireless pulse oximeter is low power management without compromising signal quality. This research investigated the advantage gained by increasing the area of the photodetector and decreasing the light emitting diode (LED) driving currents to reduce the overall power requirement of a reflectance mode pulse oximeter sensor. In vitro and preliminary in vivo experiments were conducted to evaluate a multiple photodetector reflectance sensor setup to simulate a varying detection area. It was concluded that a reflection pulse oximeter sensor employing a large area photodetector is preferred over a similar transmission type sensor for extending the battery life of a wireless pulse oximeter intended for future telemedicine applications.
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Ülker, Muhammed Akif. "Balancing of Wind Power : Optimization of power systems which include wind power systems." Thesis, Högskolan på Gotland, Institutionen för kultur, energi och miljö, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hgo:diva-1335.
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In the future, renewable energy share, especially wind power share, in electricity generation is expected to increase. Due to nature of the wind, wind power generation pattern includes uncertainties which affects the energy prices in the electricity markets. New simulations are needed for efficient planning process for the resources in the power systems to address the uncertainties in demand, generation, legal, economical and technical limitations. In this study, the aspects of planning process for wind power generation is described and some example scenarios are implemented with the help of MATLAB software.
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Schöne, Robert, Thomas Ilsche, Mario Bielert, Daniel Molka, and Daniel Hackenberg. "Software Controlled Clock Modulation for Energy Efficiency Optimization on Intel Processors." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-224966.
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Current Intel processors implement a variety of power saving features like frequency scaling and idle states. These mechanisms limit the power draw and thereby decrease the thermal dissipation of the processors. However, they also have an impact on the achievable performance. The various mechanisms significantly differ regarding the amount of power savings, the latency of mode changes, and the associated overhead. In this paper, we describe and closely examine the so-called software controlled clock modulation mechanism for different processor generations. We present results that imply that the available documentation is not always correct and describe when this feature can be used to improve energy efficiency. We additionally compare it against the more popular feature of dynamic voltage and frequency scaling and develop a model to decide which feature should be used to optimize inter-process synchronizations on Intel Haswell-EP processors.
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Rusek, Bartosz [Verfasser]. "Digital Modeling and Simulations of High Voltage Circuit Breaker Failures for Optimization of Sensor Technique / Bartosz Rusek." Aachen : Shaker, 2007. http://d-nb.info/1166512703/34.
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Törnqvist, Joacim. "Non-contact High Voltage Measurements: Modeling and On-site Evaluation." Thesis, Umeå universitet, Institutionen för fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-59934.
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In the high voltage grid, voltage measurements are made in dedicated voltage-transformers. These devices are expensive and insulation failures could impact directly on the system, and even cause a power outage. A non-contact measurement technique, on the other hand, does not require a connection to the conductors, and the sensors can therefore be much cheaper by avoiding the need for high voltage insulation. A capacitive coupling between three measurement electrodes, close to ground, and a high voltage three phase conductor system is used to model and measure the electric field and thereby determine the potentials of the conductors. A 2D-model is used for simulations, where the sensors are modeled as ideal, the conductors are modeled in an infinite wire approximation, and the ground plane is approximated as a perfect conductor. For non-ideal sensors a transfer function from the potentials on the measurement equipment to the potentials on the conductors is derived as a lumped-circuit model. The L2-norm errors for the amplitude and the phase in the reconstructed signals are calculated and measured for various sensor distances. Simulations show that the sensor distance should not be larger than the conductor distance to mitigate the erroneous effects from distance uncertainties. The optimal sensor distance depends on the quota between the height from the sensors to the conductors and the conductor distance. Measurements show, in accordance with the theory, that the sensor distance should not be larger than the conductor distance. To reduce the amplitude and phase shift errors the sensors should be placed close to the ground. For applied load resistances there is a tradeoff between amplitude- and phase shift errors. Additionally, higher load resistances attenuate higher frequencies. Measurements have verified that this technique is capable of detecting high harmonics and transients. The relatively low cost and the movability makes this method highly applicable for quick diagnostics on many locations in a grid, where the data can be evaluated on-site using computer based scripts.<br>I kraftnät utförs idag högspänningsmätningar av spänningstransformatorer. Dessa är dyra, och isolationsproblem kan ha en direkt effekt på kraftnätet, och till och med skapa strömavbrott. En beröringsfri mätmetod, å andra sidan, kräver ingen direkt koppling mellan mätutrustningen och ledarna. Sensorerna kan därmed bli billigare eftersom de inte behöver högspänningsisoleras. En kapacitiv koppling mellan tre stycken mätelektroder, placerade nära jordplanet, och ett högspänt trefasledarsystem används för att modellera och mäta det elektriska fältet och därigenom bestämma ledarnas potentialer. En 2D-modell används för simuleringar, där sensorerna modelleras som ideala, ledarna modelleras enligt en raktrådsapproximation (oändligt långa raka ledare), och jordplanet approximeras vara en perfekt ledare med oändlig utsträckning. För icke-ideala sensorer härleds en överföringsfunktion från den uppmätta potentialen på mätutrustningen till ledarnas potentialer som en analog kretsmodell. L2-norm-felen för amplitudfel och fasfel för de rekonstruerade signalerna beräknas och mäts för olika sensoravstånd. Simuleringar visar att sensoravståndet inte bör vara större än ledaravståndet för att dämpa felinverkande effekter från osäkerheter i avståndsuppskattningar. Det optimala sensoravståndet beror på kvoten mellan höjden från sensorerna till ledarna och ledaravståndet. Mätningar visar, i enlighet med teorin, att sensoravståndet inte bör vara större än ledaravståndet. För att reducera amplitud- och fasfel bör sensorerna placeras nära jordplanet. För påkopplade lastresistanser gäller att det är en byteshandel mellan amplitud- och fasfel. För övrigt gäller att högre lastresistanser dämpar högre frekvenser. Mätningar verifierar att denna teknik är kapabel att detektera höga frekvenser och transienter. Den relativt låga kostnaden och metodens rörlighet gör att den kan appliceras för snabbdiagnostik på många punkter i ett kraftnät, där det insamlade datat kan utvärderas på plats med hjälp av datorbaserade skript.
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Johari, Pritesh N. "Distributed Decap-Padded Standard Cell based On-Chip Voltage Drop Compensation Framework." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1235504983.
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Benoit, Clémentine. "Models for investigation of flexibility benefits in unbalanced low voltage smart grids." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT056/document.
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Cette thèse porte sur l'étude des apports de la flexibilité dans les réseaux Smart Grids Basse Tension. Ces derniers étant fondamentalement différents des réseaux Moyennes et Hautes Tensions, la gestion des flexibilités BT ne peut être calquée sur celle des réseaux MT et HT. De nouveaux moyens de contrôle doivent donc être développés. L'apport de ces flexibilité est analysé selon deux principaux bénéfices: la gestion opérationnelle la réduction de la pointe. Le premier apport porte donc sur le maintien des variables critiques à l'interieur des contraintes admissibles. Le but est de pouvoir gérer le réseau au plus près de ses limites, et donc d'éviter d'avoir à le renouveler, nottament en cas d'insertion importante de production décentralisée ou de véhicules électriques. La flexibilité utilisée est la gestion coordonnée des production décentralisées (puissances actives, réactives et phase de connection) et d'un régleur en charge. Le second porte sur la réduction de la pointe de consommation, soit au niveau du transformateur, soit au niveau national. La flexibilité utilisée est le délestage du chauffage électrique pendant une courte durée, suivie d'un rebond de puissance lorsque le chauffage est rallumé<br>This thesis investigates the potential contributions of flexibilities in Low Voltage Smart Grids. These networks are intrinsically different than Medium and High Voltages networks, so that the control of LV flexibilities cannot be directly taken from MV and HV networks, and new methods should be developed. The contribution of these flexibilities is studied through two main benefits: improved network operation and peak shaving. The first benefit focuses on maintaining the critical variables within the admissible constraints. The objective is to manage the network closer to its limits, reducing the need for margins, and therefore the need for upscaling. This is especially true in case of significant insertion of distributed generations or electric vehicles. The studied flexibility is the coordinated management of decentralized generation (active and reactive powers, phase switch) and a tap changer. The second benefit concerns the reduction of the peak consumption, either at the transformer, either at the national level. The studied flexibility is the shedding of electric heating for a short time, followed by a rebound when the heating is turned back on
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Chandrappa, Kori Vinay Kumar, and Ganesan Gowtham Prasath Radhakrishnan. "Design optimization and testing of electrical connector for low voltage transmission cabinets : In collaboration with ABB AB Kabeldon." Thesis, Högskolan i Halmstad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40761.
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Abstract: This thesis work was a part of Halmstad University’s Mechanical Masterprogramme curriculum done in favour of ABB Alingsås. Our industrial partnerproduces and manufactures low voltage electrical distribution cabinets, connectorsand switch gears. This project is focused on specific electrical connector used inABB’s trademark cabinets. These electrical connectors serve as both the input and output points for thedistribution cabinets. The product under scope is an extension connector calledADI3M which is used in conjunction with the large sized cable connectors(AD300). This is a sequential design optimization activity performed after theredesigning of the AD300 to ensure interface compatibility and also aimed atopportunistic cost reduction. The ADI3M should provide design compatibility withboth old and new AD300 connector designs along with the comfortable interfacinginside the CDC and SDC cabinets. With the design process and concepting knowledge gained from the course work inHalmstad university along with the ABB’s industrial exposure towards the powersupply networks we proposed four different design concepts. These design conceptswere then evaluated against interface compatibility, cost aspects, manufacturingreadiness, mechanical strength, heat generation and electricity conductionproperties. Among the product development techniques, we applied QFD processto generate the concepts, waterfall method to frame the engineering design processflow and morphological matrix to select the generated concepts. We then changedthe raw material from brass to aluminium and extrusion process due to its beneficialproperties compared to brass and copper with various other reasons explainedclearly in the thesis content. For the plastic cover we preferred poly-carbonate dueto requirements such as transparency, stiffness, etc. Two of the best feasibleconcepts were selected and the design proposals were prototyped using 3D printingtechnology. The 3D printing method used was fused deposition modelling (FDM).Later machined aluminium prototypes were then produced for the metalsubcomponents to do real time strength analysis and interface checks. Weperformed a theoretical product strength analysis using ANSYS19.2. Then resultswere then evaluated, and the final concept was chosen according to the factors suchas cost impact, easy installation and comfortable inter-component clearance.Finally, the prototypes were tested for IP rating fulfilment and compatible interfaceswith adjacent components. The consecutive activities to be done out of thesis scope is to conduct mechanicaland tests and record the performance. The future scope of this project is to developa hybrid design combining the AD300 and ADI3M connectors which would enableeasy product handling, simplified functionality and further reduce cost.
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Usman, Muhammad. "Novel Methodologies for the Analysis and Management of Low Voltage Active Distribution Networks." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3424891.
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The continuous proliferation of renewable Distributed Energy Resources (DERs) in Medium Voltage (MV) and Low Voltage (LV) Distribution Networks (DNs) is playing a prominent role in reducing the carbon footprint of fossil-fuel-based electricity generation plants. However, the rapid integration of these resources has also changed the passive nature of these networks, and consequently, special attention is required to ensure their optimal, secure and reliable operation. Moreover, the installed DERs cannot be simply operated on the basis of a fit-and-forget policy due to the emergence of several technical problems caused by their interconnection. Issues such as voltage unbalance, reverse power flow, unintentional islanded operation etc. are frequently occurring in these networks which, in turn, require novel control and management schemes to ensure the continuous supply of electricity to end-users. In this context, several countries and network operators have updated their grid codes which put additional constraints on renewable DERs to participate in the provision of ancillary services in the context of maintaining network stability.
In view of this, multi-phase analysis of MV and, especially, LV networks gains unprecedented attention due to the non-capability of single-phase equivalent representation-based network analysis approach in depicting the true picture of system’s operating conditions and state variables. Such a detailed network analysis, in turn, sets the path for innovative solutions to effectively manage these networks. Furthermore, concerning LV DNs, neutral conductor must be treated like phases conductors due to the significant presence of current in it under highly unbalanced network loading scenario. Resultantly, the application of the Kron reduction methodology to these networks must be avoided because of its reliance upon the unrealistic assumption of an equipotential neutral conductor. Since LV active DNs will become a central pillar of a decentralized electrical grid in near-future, it is, therefore, incumbent to analyse and manage them by taking into account each aspect of their structure.
With a special emphasis and focus on LV active DNs, this thesis presents novel analysis and management techniques for such networks by taking into account the explicit representation of both phases and neutral conductors in the context of losses management, which includes both losses minimization and losses allocation concepts in its scope. Regarding the latter notion, a novel multi-phase losses allocation procedure is proposed which avoids allocating neutral losses to phases conductors and, consequently, provides explicit information about phase- and neutral-losses allocation factors. The proposed approach successfully takes into account the impact of unbalanced loading through self- and mutualvariable losses coefficients while allocating losses to end-users. Based on the information provided by positive neutral losses allocation factors, a novel unbalance reduction strategy is further developed which allows the commutation of loads from heavily loaded phases of a critical node to its lightly loaded phases and, therefore, improves network balancing significantly.
In the framework of losses reduction, a multi-phase Optimal Power Flow (OPF) model based on Semi-Definite Programming (SDP) technique is formulated which successfully incorporates neutral conductors as well as wye- and delta-connected loads in its formulation. Moreover, a novel complex voltage variable-based approach is proposed for the incorporation of a complete ZIP load in the proposed relaxation. However, due to excessively high computational requirements of this relaxation in the case of medium- and large-size DNs, a cheap SDP-based OPF model is additionally proposed and three novel propositions are developed in this context for the modelling of constant current loads. The proposed cheap relaxation can be practically realized due to its low computational requirements and provision of exact solution under a range of ZIP load parameters. However, due to the dominance of multi-phase SDP-based approach over cheap SDP-based relaxation, the latter relaxation is further tightened by imposing additional constraints in the form of convex envelopes. As a result, a tight solution is obtained without making any compromise on the computational benefits of cheap SDP-based OPF relaxation.
Finally, all the proposed strategies are simulated on several test cases to demonstrate their positive potential in the context of LV active DNs management.
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Hu, Manli [Verfasser]. "Modeling, optimization and control design for LCC resonant converter applied in very low frequency high voltage generator / Manli Hu." Paderborn : Universitätsbibliothek, 2014. http://d-nb.info/1049520149/34.
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Cons, Bacilla Ferreira Daniel Gebbran. "Coordination of Distributed Energy Resources using Distributed Optimal Power Flow." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/26155.
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Electrical power systems are deemed as one of the most complex systems mankind has built to date. Nonetheless, continuous changes on electricity generation and consumption are increasing the complexity of these systems. The uptake of behind-the-meter distributed energy resources (DER) (such as rooftop PV, battery systems, and flexible loads) requires a more precise coordination of all agents in the grid. This is particularly true for distribution systems, which are traditionally passive systems but require coordination under a high percentage of DER penetration. To perform such coordination, the centralized power system operation paradigm becomes incapable of handling the necessary information flow and computation burden required.
Distributed coordination methods offer an alternative to this paradigm. In particular, distributed AC optimal power flow (DOPF) solved using a prosumer-based decomposition emerge as an effective tool for three main reasons: (i) they explicitly consider network constraints in their formulation, (ii) they permit a prosumer-based decomposition, which retains prosumer privacy and prerogative, and (iii) they computationally scalable.
Distributed methods are further bolstered by the advances on technology systems towards an IoT, edge-computing scenario. The miniaturization of sensors and computing devices, and reliable and efficient telecommunication technologies, allow for deployment of coordination methods with progressively smaller investments.
The present dissertation expands the frontiers of DER coordination, offering advances on both implementation aspects by presenting practical considerations on actual distributed, edge-computing hardware, as well as developing novel formulations for more advanced problems which assume realistic design considerations, a key to implementing DER coordination in real-world settings.
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Ivanenko, Yevhen. "Estimation of electromagnetic material properties with application to high-voltage power cables." Licentiate thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-64265.
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Efficient design of high-voltage power cables is important to achieve an economical delivery of electric power from wind farms and power plants over the very long distances as well as the overseas electric power. The main focus of this thesis is the investigation of electromagnetic losses in components of high-voltage power cables. The objective of the ongoing research is to develop the theory and optimization techniques as tools to make material choices and geometry designs to minimize the high-frequency attenuation and dispersion for HVDC power cables and the power losses associated with HVAC cables. Physical limitations, dispersion relationships and the application of sum rules as well as convex optimization will be investigated to obtain adequate physical insight and a priori modeling information for these problems. For HVAC power cables, the objectives are addressed by performing measurements and estimation of complex valued permeability of cable armour steel in Papers I and II. Efficient analytical solutions for the electromagnetic field generated by helical structures with applications for HVAC power cables have been obtained in Paper III. For HVDC power cables, estimation of insulation characteristics from dielectric spectroscopy data using Herglotz functions, convex optimization and B-splines, has been investigated in Papers V and VI. The unique solution requirements in waveguide problems have been reviewed in Paper IV.
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Am, Sokchea. "Power modules design and optimization for medium power of MMC inverters : high insulation voltage gate driver system and 3D packaging." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT095/document.
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Dans cette recherche, l'auteur met l'accent à la fois sur une optimisation de la conception pour une (MV-MMC: Medium Voltage Modular Multilevel Converter) utiliser comme un DC/AC ou AC/DC et à deuxième fois sur la grille pour les modules IGBT qui sont utilisés dans ce type d'application. Par exemple, les convertisseurs de MMC sont utilisés dans les systèmes d'alimentation des navires électriques avec les buses de moyenne tension de courant continu (en anglais: medium-voltage direct current (MVDC)). Pour une telle application, selon le document IEEE, la tension du bus DC peut être jusqu'à 35kV. Par conséquent, les systèmes de commande rapprochée pour piloter le grille des modules IGBT pour les applications MVDC-MMC sont des principaux problèmes en termes d'architectures et des besoins de haute isolation galvanique. Ainsi, cette thèse fournit des solutions pour répondre à ces problèmes. L'étude inclut également les études d'un matériau diélectrique qui est utilisé comme matériau d'isolation. Les résultats des essais expérimentaux d'un matériau diélectrique proposé pour différentes épaisseurs des couches pour maintenir des niveaux de tension d'isolation sont également fournis pour valider clairement cette étude. En effet, un convertisseur MMC compose d'un certain nombre de cellules de conversion connectés en série. Une cellule (sous-module de convertisseur) est classiquement constitué de deux modules IGBT. Sur la base de la topologie de la cellule, l'architecture d'un pilote de grille contestée pour les modules de puissance à semi-conducteurs est proposée et comparée à celle classique en termes de besoins des niveaux de tension d'isolation galvanique, la taille de la cellule de convertisseur, etc<br>In this research, the author focuses on both a design optimization for a Medium Voltage Modular Multilevel Converter (MV-MMC) use as a DC/AC or AC/DC converter and gate drivers systems for IGBT modules which are used in this kind of application. For example, the MMC converters are used in Medium-Voltage Direct Current (MVDC) electrical ship power systems. For such application, according to IEEE document, the DC bus voltage can be up to 35kV. Hence, gate drivers’ systems for IGBT modules for MVDC-MMC applications are major concerns in terms of architectures and insulation voltage capabilities. Thus, this dissertation provides solutions to answer these problems. The study also includes the studies of a dielectric material which is used as insulation material. The results of experimental tests of a proposed dielectric material for different layers thicknesses to sustain different insulation voltage levels are also provided to clearly validate this study. Actually, a MMC converter composes of a number of converter cells connected in series. One cell (converter’s sub-module) is classically composed of two IGBT modules. Based on the cell topology, a challenged gate driver’s architecture for power semiconductor modules is proposed and compared to the classical one in terms of high and low galvanic insulation voltage levels’ requirements, converter’s cell size, etc
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Padilha, Lucas Nery. "Análise comparativa de estratégias para regulação de tensão em sistemas de distribuição de energia elétrica na presença de geradores distribuídos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-10082010-141601/.
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Para que a instalação de geração distribuída possa de fato beneficiar a operação das redes de distribuição e de subtransmissão de energia elétrica, seus impactos técnicos devem ser cuidadosamente estudados, sobretudo em redes de distribuição, as quais foram inicialmente planejadas para operar com fluxo de potência unidirecional. Dentre esses impactos, a influência da geração distribuída na regulação da tensão é um aspecto de suma importância, pois está diretamente relacionada à qualidade do fornecimento da energia elétrica aos consumidores. Neste contexto, é importante conhecer e dispor de meios para controlar a interação entre esses geradores e os dispositivos convencionais de regulação de tensão (transformadores com comutadores de tap sob carga, bancos de capacitores e reguladores de tensão) para que a tensão de suprimento permaneça dentro da faixa de valores admissíveis. Assim, este projeto de pesquisa propõe uma análise comparativa entre diferentes estratégias de operação de dispositivos reguladores de tensão em sistemas de distribuição com a presença de geradores distribuídos. Algumas das metodologias discutidas aqui são bastante consolidadas e usualmente aplicadas na operação de sistemas de distribuição de energia elétrica e em trabalhos acadêmicos, enquanto outras são sugeridas por este mesmo trabalho. Tais estratégias são propostas como problemas de otimização não linear inteira mista em que se consideram diferentes modos de operação dos geradores distribuídos e duas funções-objetivo distintas, tratadas de forma independente: minimização dos desvios de tensão nas barras e minimização das perdas elétricas. Os resultados da aplicação de cada estratégia de operação são apresentados e é realizada uma análise qualitativa das vantagens e desvantagens de cada uma. Tem-se até o momento um conjunto de informações que podem servir de suporte na configuração de características operativas e definição de parâmetros de controle para o sistema de regulação de tensão das redes de distribuição de energia elétrica.<br>In order to assure that the installation of distributed generation would improve the operation of distribution and subtransmission networks, its technical impacts should be carefully studied, especially in distribution networks, which were originally designed to operate with unidirectional power flow. Among these impacts, the influence of distributed generation on voltage regulation is a very important aspect because it is directly related to the quality of electricity supply to the consumers. In this context, it is important to know and employ means of controlling the interaction between these generators and conventional voltage regulation devices (transformers with on-load tap changers, shunt capacitor banks and voltage regulators) assuring that the voltage supply remains within the range of permissible values. Thus, this work proposes a comparative analysis among different operational strategies of voltage regulation devices in distribution systems in the presence of distributed generators. Some of the methodologies discussed here are fairly consolidated and usually applied in power industry and academic researches, while others are suggested by this work. Such strategies are proposed as mixed integer nonlinear programming problems considering different operation modes of distributed generators and two different objective functions, treated independently: minimization of voltage deviations and minimization of power losses. The results of each operation strategy application are presented and a qualitative analysis of the advantages and disadvantages of each one is performed. So far, a set of information that may provide support to configure operating characteristics and define control parameters of voltage regulation system in power distribution networks has been generated.
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Hsiao, Yuan Chao, and 蕭元超. "Clock Skew Optimization for Voltage Variation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/2j26u4.
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碩士<br>國立清華大學<br>資訊工程學系<br>104<br>Clock skew minimization has been extensively studied. However the problem is still difficult to resolve because clock skew needs to satisfy many different environmental corners. It has been known that optimizing skew at one corner may cause timing violation at another corner. Traditionally, skew optimization may require iterations of optimization among various corners which can take the very long time or even fail the constraints. We observe in several real designs that the clock skew problem can be easily solved if the library has special clock buffers. In this paper, we propose a novel buffer design called wide-divergence buffers (WDBs), whose delay under the low voltage (the worst corner) is about several times of the delay under the high voltage (the best corner). We first describe how a WDB can be implemented using analog techniques. Then, we also propose an efficient optimization framework for WDB customization. Our experimental results consistently show that the total negative slack (TNS) reduce 84.23% for industrial design.
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Lee, Ying-Chen, and 李映辰. "Energy Optimization with Task scheduling and Voltage selection for Variable voltage Processors." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/28129232280966781322.
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碩士<br>國立東華大學<br>資訊工程學系<br>94<br>In this thesis, we propose a task scheduling and voltage allocation technique indynamically variable voltage processors, the purpose of which is minimization of processor energy consumption. Task scheduling is a technique to minimizepower consumption with task assignment and ordering. In the static voltage scheduling technique, the CPU time and supply voltage are assigned to tasksin order to minimize the total energy consumption. In this thesis, we formulate the problem as an integer linear programming problem with constraints on the dependency tasks. We extend the problem to include the case in which each task may have di
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Tsai, Chi-Chang, and 蔡繼章. "Optimization of a Steady-Voltage Piezoelectric Transducer." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/82332597116477168298.
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碩士<br>國立中山大學<br>海洋環境及工程學系研究所<br>100<br>Mechanical energy exists all over the place in our living, and vibration is the most common way of mechanical performance. Micro-electromechanical systems, the application which integrate techniques and combine different field of research, make it possible to convert vibration into electrical energy by using piezoelectric materials; moreover, it become a small piezoelectric power generator.
The thesis set up an equivalent circuit model based on the principle of piezoelectric and cantilever mechanics for experimenting the model’s exactness; consequently, model shows that resonant frequency has no effect on generate electricity when amplitude was fixed.
The thesis attempts to change the shape of unimorph for enhancing its power generation. By using different sharp of unimorph, the experiment demonstrate that power generation have direct ratio with frequency at amplitude of 5mm. Moreover, different shapes of the unimorph at frequency of 16Hz have different power output; the disparity among power output might up to 1.78 times.