O trabalho apresentado tem como objetivo principal pesquisar e demonstrar através de simulações as implicações da utilização de motores de alto rendimento com viés de Eficiência Energética. Além disso, pretende-se estabelecer uma ligação entre o uso eficiente da energia com a possibilidade dos leilões de eficiência energética virem a se tornar uma realidade no Brasil. É de fundamental importância que se tenha a preocupação com sistemas de conservação de energia e não somente com novas fontes de geração. A eficiência Energética vem ganhando cada vez mais espaço no setor elétrico, se tornando muito mais que um indicador, mas também uma forma de tornar o sistema mais robusto e capaz de suprir deficiências por problemas estruturais. Procurou-se demonstrar o cenário atual da matriz energética atual, conceituar leilões de eficiência energética e os certificados brancos que é um subproduto deste. Por fim, realizou-se várias simulações estudando a substituição dos motores de alto rendimento e os ganhos técnicos e financeiros atrelados aos leilões de eficiência energética. Além disso, foi demonstrado também o impacto da utilização dos motores de alto rendimento em leilões de eficiência energética por segmentos da indústria brasileira. / The present study has as main objective the analysis, through simulations, of the implications of the use of energy efficient motors with a bias of energy Efficiency. In addition, we intend to establish a link between the efficient use of energy with the possibility of auctions for energy efficiency become a reality in Brazil. It is also important to have concerns with energy conservation systems and not only with new sources of generation. Energy efficiency is becoming an increasingly common concern in the electricity sector, being much more than an indicator but also a way to make the system more robust and capable of mitigating deficiencies which occur by structural problems. In this work we tried to present the current energy scenario and define the energy efficiency auctions as well as its byproduct, the white certificates. Finally, we carried out several simulations studying the replacement of common electrical motors by high efficiency ones in order to analyse the technical and the financial gains linked to energy efficiency auctions. In addition, we also demonstrated the impact of the use of high efficiency motors by sectors of brazilian industry in the energy efficiency auctions.

O trabalho apresentado tem como objetivo principal pesquisar e demonstrar através de simulações as implicações da utilização de motores de alto rendimento com viés de Eficiência Energética. Além disso, pretende-se estabelecer uma ligação entre o uso eficiente da energia com a possibilidade dos leilões de eficiência energética virem a se tornar uma realidade no Brasil. É de fundamental importância que se tenha a preocupação com sistemas de conservação de energia e não somente com novas fontes de geração. A eficiência Energética vem ganhando cada vez mais espaço no setor elétrico, se tornando muito mais que um indicador, mas também uma forma de tornar o sistema mais robusto e capaz de suprir deficiências por problemas estruturais. Procurou-se demonstrar o cenário atual da matriz energética atual, conceituar leilões de eficiência energética e os certificados brancos que é um subproduto deste. Por fim, realizou-se várias simulações estudando a substituição dos motores de alto rendimento e os ganhos técnicos e financeiros atrelados aos leilões de eficiência energética. Além disso, foi demonstrado também o impacto da utilização dos motores de alto rendimento em leilões de eficiência energética por segmentos da indústria brasileira. / The present study has as main objective the analysis, through simulations, of the implications of the use of energy efficient motors with a bias of energy Efficiency. In addition, we intend to establish a link between the efficient use of energy with the possibility of auctions for energy efficiency become a reality in Brazil. It is also important to have concerns with energy conservation systems and not only with new sources of generation. Energy efficiency is becoming an increasingly common concern in the electricity sector, being much more than an indicator but also a way to make the system more robust and capable of mitigating deficiencies which occur by structural problems. In this work we tried to present the current energy scenario and define the energy efficiency auctions as well as its byproduct, the white certificates. Finally, we carried out several simulations studying the replacement of common electrical motors by high efficiency ones in order to analyse the technical and the financial gains linked to energy efficiency auctions. In addition, we also demonstrated the impact of the use of high efficiency motors by sectors of brazilian industry in the energy efficiency auctions.

Wireless power transfer (WPT) technologies have become important for our everyday life. The most commonly used near-field WPT method is inductive coupling, which suffers from low efficiency and small range. The Strongly Coupled Magnetic Resonance (SCMR) method was developed recently, and it can be used to wirelessly transfer power with higher efficiency over a longer distance than the inductive coupling method. This dissertation develops new SCMR systems that have better performance compared to standard SCMR systems. Specifically, two new 3-D SCMR systems are designed to improve the angular misalignment sensitivity of WPT systems. Their power transfer efficiency for different angular misalignment positions are studied and analyzed. Prototypes are built for both systems and their performance is validated through measurement. Furthermore, new planar broadband conformal SCMR (CSCMR) systems are developed that maintain high efficiency while providing significantly larger bandwidth than standard CSCMR systems. Such broadband CSCMR systems are used here for the first time to simultaneously accomplish highly efficient wireless power transfer and high data rate communication through the same wireless link. These systems that combine wireless power and communication are expected to enable next-generation applications with battery-less and “power-hungry” sensors. Example applications include implantable and wearable sensors as well as embedded sensors for structural health monitoring.

Ces travaux de thèse se concentrent sur la conception d'amplificateur de puissance MMIC large-bande haut rendement en technologie GaN pour des applications militaires de type radar et guerre électronique. Les objectifs principaux sont de proposer des structures innovantes de combinaison de puissance notamment pour réduire la taille des amplificateurs actuels tout en essayant d'améliorer leur rendement dans le même temps. Pour cela, une partie importante de ces travaux consiste au développement de combineurs de puissance ultra compactes et faibles pertes. Une fois ces combineurs réalisés et mesurés, ils sont intégrés dans des amplificateurs de puissance afin de prouver leur fonctionnalité et les avantages qu'ils apportent. Différents types d'amplificateur tant au niveau de l'architecture que desperformances sont réalisés au cours de ces travaux. / This work focus on the design of wideband and high efficiency GaN MMIC high power amplifiers for military applications such as radar and electronic warfare. The main objectives consist in finding innovative power combining structures in order to decrease the overall size of amplifiers and increasing their efficiency at the same time. For these matters, an important part of this work consisted in the design and realization of ultra compact and low loss power combiners. Once the combiners realized and measured, they are integrated into power amplifiers to prove their functionality and the advantages they bring. Several kind of amplifiers have been realized whether regrind their architecture or their performances.

An interesting alternative for today's high efficiency variable speed drives is the Permanent Magnet-Assisted Synchronous Reluctance Motor drive, which belongs to the family of brushless synchronous AC motor drives. Generally, the reluctance torque of this motor is significant compared to the Permanent Magnet electrical torque. The advantage of increased reluctance torque is the decreased need of expensive permanent magnet (PM) material, which makes this solution thus cheaper than the respective permanent magnet motor. Also due to its synchronous operation, sensorless rotational control is possible along with higher power factor and better efficiency compared to the induction motor (IM). Therefore, this thesis first deals with the implementation of a vector control strategy for speed control of the PMa-synRM motor that can be applied to a washing machine application. The machine is supplied by a current controlled voltage source PWM inverter to control the instantaneous stator currents which are decided by the reference speed. Secondly, the thesis focuses on the sensorless speed operation of the PMa-SynRM to take advantage of the lower costs as well as increased system reliability which otherwise is not possible using the delicate speed or position sensors. The concept involves estimation of the rotor speed and/or position. There are several speed estimation techniques proposed by researchers and among them the observer based technique is proven and commonly used in the industry. The only requirements of the observer system are a very fast signal processor, specialized and optimized to perform complex mathematical calculations. The feasibility and effectiveness of the control techniques are verified using the experimental results, implemented using the Texas Instruments TMS320F2812 eZDSP controller board and the overall motor drive system in the laboratory.

This thesis focuses mainly on the techniques to achieve high-performance top-emitting OLEDs, regarding device efficiency and lifetime for both non-inverted and inverted structures. It is thus organized as follows: In Chapter 2, the basic physics of organic semiconductor materials are reviewed, including the electronic properties of organic semiconductor materials, molecular excitations and their electronic transitions etc., which are believed to be critical for understanding of the work. Then, the general device physics of OLEDs are reviewed in detail, which includes almost every important electrical and optical process involved in the device. Finally, techniques and methods used to improve the device performance are summarized, which includes electrical doping of charge carrier transport layers. In Chapter 3, all organic materials, experimental techniques, and characterization methods used in this study are briefly described. In the following Chapter 4, techniques that are used for device optimization of non-inverted top-emitting OLEDs are discussed. Also, the mechanism of light outcoupling enhancement by a capping layer is discussed there. In the last part of Chapter 4, the influence of the optical device structure on the intrinsic quantum yield of the emitters is studied. Chapter 5 is focused on inverted top-emitting OLEDs, which are believed to be better applicable with current mainstream n-type amorphous silicon thin film transistor (TFT) technology. In this Chapter, the organic/metal and metal/organic interfaces are investigated in detail and their influence on device performance is discussed. In Chapter 6, the degradation of top-emitting OLEDs is studied, with a focus on the influence of electrode material and electrode thickness on the lifetime of top-emitting devices.

In the crystalline Si solar cell industry, there is a push to reduce module cost through a combination of thinner substrates and increased cell efficiency. Achieving solar cells with sub-100 µm substrates cost-effectively is a formidable task because such thin substrates impose stringent handling requirements and thermal budget due to their flexibility, ease of breakage, and low yield. Moreover, as the substrate thickness decreases the surface passivation quality dictates the performance of the cells. Crystalline Si heterojunction (HJ) solar cells based on hydrogenated amorphous silicon (a-Si:H) have attracted significant interest in recent years due to their excellent surface passivation properties, potential for high efficiency, low thermal budget and low cost. HJ cells with ultra-passivated surfaces showing > 700 mV open-circuit voltages (Voc) and > 20% conversion efficiency have been demonstrated. In these cells, it has been identified that high-quality a-Si:H films deposited by a low-damage plasma process is key to achieving such high cell performance. However, the options for low-damage plasma deposition process are limited. The main objectives of this work are to develop a low-plasma damage a-Si:H thin film deposition process based on remote plasma chemical vapor deposition (RPCVD) and to demonstrate high efficiency HJ solar cells on bulk substrates as well as on ultra-thin silicon and germanium substrates obtained by a novel, low-cost semiconductor-on-metal (SOM) technology. This manuscript presents a detailed description of the RPCVD system and the process leading to the realization of high quality a-Si:H thin films and high efficiency HJ solar cells. First, p-type a-Si:H thin films are developed and optimized, then HJ solar cells are subsequently fabricated on bulk and ultra-thin Si and Ge SOM substrates without intrinsic a-Si:H passivation. Single HJ cells on ~ 500 µm bulk Si and ~25 µm ultra-thin substrates exhibited conversion efficiencies of η = 16% (Voc = 615 mV, Jsc = 34 mA/cm2, and FF = 77%) and η = 11.2% (Voc = 605 mV, Jsc = 29.6 mA/cm2, and FF = 62.8%), respectively. The performance of the ~25 µm cell was further improved to η = 13.4% (Voc = 645 mV, Jsc = 31.4 mA/cm2, and FF = 66.2%) by implementing the dual HJ architecture without front side i-layer passivation. For single HJ cells based on Ge substrates, the results were η = 1.78 % (Voc = 148 mV, Jsc = 35.1 mA/cm2, and FF = 1.78%) on ~500 µm bulk Ge, compared to η =5.3% (Voc = 203 mV, Jsc = 44.7 mA/cm2, and FF = 5.28%) on ~ 50 µm Ge SOM substrates. Respectively, the results obtained on ultra-thin SOM substrates are among the highest reported in literature for based on comparable architecture and substrate thickness. In order to achieve improved cell performance, dual HJ cells with i-layer passivation of both surfaces were fabricated. First, optimized RPCVD-based i-layer films were developed by varying the deposition temperature and H2 dilution ratio (R). It was found that excellent surface passivation on planar substrates with as-deposited minority carrier lifetimes > 1 ms is achievable by using deposition temperature of 200 ºC and moderate dilution ratio 0.5 ≤ R ≤ 1, even without the more rigorous RCA pre-cleaning process typically used in literature for achieving comparable results. Subsequently, dual HJ solar cells with i-layer films were demonstrated on planar and textured bulk Si substrates showing improved conversion efficiencies of η = 17.3% (Voc = 664 mV, Jsc = 34.34 mA/cm2 and FF = 76%) and η = 19.4% (Voc = 643 mV, Jsc = 38.99 mA/cm2, and FF = 77.5%), respectively. / text

The absorption of the sun's radiation and its efficient conversion to useful work by a photovoltaic solar cell is of interest to the community at large. Scientists and engineers are particularly interested in approaches that exceed the Shockley-Queisser limit of photovoltaic solar-energy conversion. The abstract notion of increasing the efficiency of photovoltaic solar cells by constructing a three-transition solar cell via an absorber with intermediate levels is well-established. Until now, proposed approaches to realize the three-transition solar cell do not render the efficiency gains that are theorized; therefore, researchers are experimenting to ascertain where the faults lie. In my opinion, it is unclear if the abstract efficiency gains are obtainable. Furthermore, it is difficult to determine whether three-transition absorbers are even incorporated in the existing three-transition solar cell prototypes. I assert that there are material systems derived from the technologically important compound semiconductors and their ternary alloys that more clearly determine the suitability of employing nanostructured absorbers to realize a three-transition solar cell. The author reports on a nanostructured absorber composed of InAs quantum dots completely enveloped in a GaAsSb matrix that is grown by molecular beam epitaxy. The material system, InAs/GaAs$_{0.88}$Sb$_{0.12}$, is identified as an absorber for a three transition solar cell. This material system will more easily determine the suitability of employing nanostructured absorbers because its quantum-dot heterojunctions have negligible valence-band discontinuities, which abate the difficulty of interpreting optical experimental results. A key tool used to identify the GaAs$_{1-x}$Sb$_{x}$ ($xapprox 0.12$) is a maximum-power iso-efficiency contour plot. This contour plot is only obtainable by first having analyzed the impact of both finite intermediate-band width and spectral selectivity on the optimized detailed-balance conversion efficiencies of the three-transition solar cell. Obtaining the contour plot is facilitated by employing a rapid and precise method to calculate particle flux (Appendix~ ef{ch:Rapid-Precise}). The author largely determines the electronic structure of the InAs/GaAs$_{1-x}$Sb$_{x}$ ($xapprox 0.12$) absorber that is grown by molecular beam epitaxy from optical experimental methods and in particular, from photoluminescent spectroscopy. The interpretation of the experimental photoluminescent spectrum is facilitated by having first studied the theoretical photoluminescent spectra of idealized three-transition absorbers.

Auctions have a long history and are an effective method to distributed resources. In the era of Internet and e-commerce, electronic sealed-bid auction play an important role in business. However, it is a risk to run a sealed-bid auction through the Internet, which is an open and unreliable environment. There are many security concerns about correctness and fairness of the auction and privacy of the bidders in electronic sealed-bid auctions. Cryptology seems to be the only security solution for electronic sealed-bid auction. On the other hand, a practical electronic sealed-bid auction scheme must be efficient. So efficient application of cryptographic tools to electronic sealed-bid auction is the focus of this thesis. Firstly, security requirements of sealed-bid auctions are surveyed. The auction result must be determined correctly according to the submitted bids and the pre-defined auction rule. The bidders must compete with each other in a fair play and none of them can take advantage of others. The auction must be publicly verifiable, so that the auction result is acceptable by everyone. Usually, a losing bidder hopes to keep his bid secret, so the losing bids should be kept secret. In different applications, different auction rules may be applied. So, to avoid a tie, a large number of biddable prices must be accepted in some applications. Secondly, the currently known sealed-bid auction schemes are classified. In recent years, many sealed-bid auction schemes based on various cryptographic primitives have been proposed. Nearly all of them can be classified into five models. In the Model 1, each bid is known to the auctioneers, who can find the winning bid and winner very efficiently. Bid privacy is not implemented in Model 1. In Model 2 homomorphic bid opening is employed, so that the winning bid and winner can be found while the losing bids are kept secret. In Model 3 very strong bid privacy is achieved through a Dutch-style bid opening, which is highly inefficient. In Model 4, the link between the bids and bidders instead of confidentiality of the bids is kept secret. This kind of confidentiality is weaker than normal bid privacy and called relative bid privacy in this thesis. (Complete confidentiality of the bids in the end of the auction is called absolute bid privacy.) Implementation of relative bid privacy can be very efficient if an efficient anonymous channel can be constructed. Model 5 uses secure evaluation to open the bids and find the auction result and makes it possible to achieve absolute bid privacy efficiently. Three main cryptographic primitives are explored and employed to design new auction schemes in four auction models. The first tool is batch verification, which can improve computational efficiency in auction schemes. The second is mix network, which can be used to implement anonymous channels in Model 4 and Model 5. Two new efficient mix networks are designed and used in Model 2, Model 4 and Model 5. The third is secure evaluation, which is employed in two new auction schemes in Model 5 to achieve strong bid privacy efficiently. Other cryptographic primitives employed in the auction schemes include efficient 1-out-of-w oblivious transfer in Model 2 and key chain in Model 3. Five new auction schemes are proposed. The first scheme in Model 2 batch verifies bid validity to improve efficiency. The second scheme optimises the key chain used in Model 3 to obtain a more advanced auction scheme. The third scheme implements a concrete anonymous channel in Model 4 for the first time and achieves relative bid privacy and high efficiency convincingly. The last two employ new secure evaluation techniques to achieve absolute bid privacy and high efficiency. With these five new auction schemes, better solutions are achieved in various auction applications.

La conception des Alimentations Sans Interruption (ASI) a fait l’objet d’améliorations successives ces dernières années afin d’atteindre des niveaux de rendement avoisinant les 95% tout en minimisant leur encombrement. L’utilisation massive de l’électronique de puissance pour ces systèmes conduit à y concentrer tous les efforts de conception pour augmenter à la fois le rendement et la densité de puissance. Les développements constants en électronique de puissance offrent au concepteur des multitudes d’options, parmi elles, les topologies de puissance multi-niveaux et/ou entrelacées pour réduire le volume des composants passifs, les nouvelles technologies des matériaux semi-conducteurs avec l’introduction des composants grand gap, ainsi que l’avancée technologique sur les matériaux utilisés dans les composants passifs. Le choix entre ces options est un compromis pour atteindre les objectifs prédéfinis, particulièrement lorsque d’autres contraintes apparaissent pour limiter l’espace des solutions possibles, notamment l’aspect thermique, les limites technologiques ou les contraintes CEM. Ces travaux proposent la mise en œuvre de dimensionnements par optimisation multi-objectifs de l’ensemble du convertisseur avec toutes ses contraintes. Ceci offre un outil rapide pour comparer les différentes possibilités de conception optimale capable de quantifier le gain apporté au convertisseur par les différentes solutions. Pour ce faire, les différents choix topologiques et technologiques ont été traités par le développement de modèles multi-physiques acceptant des paramètres d’entrée discrets. Ainsi, les convertisseurs optimisés répondent naturellement aux contraintes industrielles cadrées par des catalogues de fournisseurs spécifiques. Pour ce faire, nous avons commencé par dresser les différentes contraintes énergétiques imposées sur l’ASI dans son environnement. L’identification des solutions adaptées à sa conception est réalisée à travers un état de l’art des recherches dans le domaine de l’électronique de puissance. Des modèles génériques des structures de puissance, ainsi que des modèles multi-physiques discrets des composants sont ensuite développés à la base des approches analytiques assurant le bon compromis entre précision et rapidité de calcul. Finalement, une méthodologie d’optimisation multi-objectif et multi contraintes est réalisé sur l’ensemble des solutions pour quantifier les performances atteintes par chacune d’elles. Des travaux expérimentaux nous ont été indispensables pour valider les modèles et les solutions optimales. Sur la base des résultats d’optimisation un convertisseur PFC de 4.2kW/L a été construit est ses performances ont été validées. / The design of Uninterruptible Power Supplies (UPS) has been successively improved in recent years to achieve efficiency levels of around 95% while minimizing their footprint. The massive use of power electronics for these systems is led to focus all design efforts to increase both efficiency and power density. The constant developments in power electronics provide the designer many options, among them the multi-level and/or interleaved power topologies in order to reduce passive components size, the new technologies of semiconductor materials with the introduction of grand gap components and advanced technology on passive components materials. The choice between these options is a compromise to achieve the predefined objectives, particularly when other constraints appear to limit the space of possible solutions, including thermal aspect, technological limitations or EMI constraints. This work proposes the implementation of multi-objective optimization methodology for the design of power converters with all its constraints. This offers a quick tool to compare the different possibilities of design and to quantify the improvement provided to the converter. To do this, different topological and technological choices were studied with the development of multi-physics models. These models can take discrete variables as input. So, optimized converters could meet industrial requirements covered by real components and their datasheets. To do this, we first establish the different constraints imposed on the UPS within its environment. Identifying solutions to design is carried through a state of the art research in the field of power electronics. Generic models of power structures and discrete multi-physical models of the components are then developed based on analytical approaches by ensuring a good compromise between accuracy and speed of calculation. Finally, multi-objective and multi constraints optimization methodology is performed on the set of design choices to quantify the performances achieved by each of them. Experimental work has been essential for us to validate the models and optimal solutions. Based on the optimization results PFC converter of 4.2kW/L was built is its performance has been validated.