This thesis will focus on creating electromagnetic vibration generator for a project ESPOSA. This generator will be used in aeronautical application. There it will be powering required electronics. Electronics is thought a part, which will be sensing, writing and sending required data.

The ever-increasing demand for wireless communication has led to an incentive to increase the data rate and reduce the size of communication devices, be it antennas or other components of RF front-ends. The emphasis is primarily on increasing data rate, which leads to the use of higher frequency bands and wider bandwidths in modern communication technology research and innovations. However, increasing frequency in many technology areas cannot necessarily be beneficial because of physical constraints. For example, communication under seawater or other RF harsh environment requires very-low-frequency (VLF) or ultra-low-frequency (ULF) signals to penetrate lossy media that block high-frequency signals. Furthermore, recent advances in neuroscience have demonstrated the potential of VLF and ULF electromagnetic (EM) waves for studying brain function and treating neurological conditions. The main challenge is that most VLF and ULF generators are large and power-hungry, making them impractical to use in many applications. As a result, recent approaches using permanent magnets have started to provide groundbreaking solutions that can revolutionize VLF/ULF communication. This work presents a new method for generating low-frequency EM waves for navigation and communication in challenging environments, such as underwater and underground, as well as magnetic stimulation of brain neurons. The key concept is to disturb the magnetic energy stored around a permanent magnet in a time-variant fashion. The magnetic reluctance of the medium around the permanent magnet is modulated to alter the magnetic flux intensity and direction (disturb the stored energy) in order to achieve this goal. The nonlinear properties of the surrounding magnetic material are a critical phenomenon for efficient and effective modulation. Since the proposed method of generating the EM field is not based on a second-order system (resonant structure), the bandwidth of any modulation schema is not limited to the overall system quality factor. A transmitter is prototyped as a proof of concept, and the generated field is measured. Compared to the rotating magnet, the prototyped transmitter can modulate up to 50% of the permanent magnet's stored energy with much lower power consumption. The magnetic equivalent circuit (MEC) approach is also used to analyze the transmitter. Finally, the transmitter is optimized, and the measurement results show a 7 dB improvement in efficiency compared to the primary structure. As a result of promising performance, we propose that this method be used to improve the performance of transcranial magnetic stimulation (TMS) devices. Furthermore, the comparison simulated results back up the validity of the proposed technique, revealing that focality and penetration depth are improved while utilizing much less power than traditional TMS devices. / Doctor of Philosophy / The growing demand for wireless communication has created an incentive to increase the data rate while decreasing the size of communication devices, whether they are antennas or other radio frequency (RF) components between the antenna and at least one mixing stage of a receiver and/or the power amplifier of the transmitter. The emphasis is primarily on increasing data rate, which leads to the use of higher frequency bands and wider bandwidths in modern communication technology research and innovations. However, increasing frequency in many technology areas may not be beneficial because of physical constraints. For example, communication under seawater or underground requires very-low-frequency (VLF) or ultra-low-frequency (ULF) signals to penetrate lossy media that block high-frequency signals. Furthermore, recent advances in neuroscience have demonstrated the potential of VLF and ULF electromagnetic (EM) waves for studying brain function and treating neurological conditions. The main challenge is that most VLF and ULF generators are large and power-hungry, making them unsuitable for many applications. As a result, recent approaches using permanent magnets have started to provide groundbreaking solutions that can revolutionize VLF/ULF communication. This work presents a new method for generating low-frequency EM waves for navigation and communication in challenging environments, such as underwater and underground, as well as magnetic stimulation of brain neurons. The key idea is to disturb the magnetic energy stored around a permanent magnet in a time-variant fashion. The magnetic reluctance of the medium around the permanent magnet is modulated to change the magnetic flux intensity and direction (disturb the stored energy) in order to achieve this goal. The nonlinear properties of the surrounding magnetic material are a critical factor in achieving efficient and effective modulation. Since the proposed method of generating the EM field does not rely on a second-order system (resonant structure), the bandwidth of any modulation schema is not constrained by the overall system quality factor. As a proof of concept, a transmitter is prototyped, and the generated field is measured. Compared to the rotating magnet, the prototyped transmitter can modulate up to 50% of the permanent magnet's stored energy with much lower power consumption. The magnetic equivalent circuit (MEC) approach is also used to analyze the transmitter. Finally, the transmitter is optimized, and the measurement results show a 7 dB improvement in efficiency compared to the primary structure. As a result of promising performance, we propose that this method be used to improve the performance of transcranial magnetic stimulation (TMS) devices. Furthermore, the comparison simulated results support the validity of the proposed technique, revealing that focality and penetration depth are improved while using much less power than traditional TMS devices.

In this thesis case studies have been made to study the impact ofSMES system on power system transmission with a decoupled Optimal Power Flow program. Linear Programming (LP) and Quadratic Programming (QP) storage scheduling methods including transmission security have been developed, LP method is suitable for single storage system and QP method is capable of solving multiple storage scheduling problem. Results on single storage system is compared with Load Shaving method, which indicate that three methods have approximately the same storage schedule and daily fuel cost. Results on two storage system with QP method suggest that the coordination between storage units can help to transfer more power from base units and reduce total fuel cost in peak hours. / Master of Science

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 188-200.

Jellyfish have inhabited this planet for millions of years and are the oldest known metazoans that swim using muscles. They are found in freshwater sources and in oceans all over the world. Over millions of years of evolution, they have adapted to survive in a given environment. They are considered as one of the most energy efficient swimmers. Owing to these characteristics, jellyfish has attracted a lot of attention for developing energy efficient unmanned undersea vehicles (UUVs). The goal of this thesis is to provide understanding of the different physical mechanisms that jellyfish employs to achieve efficient swimming by using analytical and computational models. The models were validated by using the experimental data from literature. Based upon these models refinements and changes to engineering vehicles was proposed that could lead to significant enhancement in propulsion efficiency. In addition to the propulsion, the thesis addresses the practical aspects of deploying a jellyfish-inspired robotic vehicle by providing insights into buoyancy control and energy generation. The thesis is structured in a manner such that propulsive and structural models inspired from the natural animal were systematically combined with the practical aspects related to ionic diffusion driven buoyancy control system and thermal -- magnetic energy harvesting system. Jellyfish morphology, swimming mechanism and muscle architecture were critically reviewed to accurately describe the natural behavior and material properties. We provide full understanding of mesoglea, which plays most significant role towards swimming performance, in terms of composition, mechanical properties and nonlinear dynamics. Different jellyfish species exhibit different microstructure of mesoglea and thus there is a wide variety of soft materials. Mechanical properties of collagen fibers that form the main constituent toward imparting elasticity to mesoglea were reviewed and analyzed. The thesis discusses the theoretical models describing the role of structure of mesoglea towards its mechanical properties and explains the variation occurring in stiffness under given experimental environment. Muscle architecture found in jellyfish, nerve nets and its interconnection with the muscles were investigated to develop comprehensive understanding of jellyfish propulsion and its reaction to external stimuli. Different muscle arrangements were studied including radial, coronal muscle, and coronal-muscles-with-breaks in-between them as observed in Cyanea capillata. We modeled these muscle arrangements through finite element modeling (FEM) to determine their deformation and stroke characteristics and their overall role in bell contraction. We found that location and arrangement of coronal muscle rings plays an important role in determining their efficient utilization. Once the understanding of natural jellyfish was achieved, we translated the findings onto artificial jellyfish vehicle designed using Bio-inspired Shape Memory Alloy Composite (BISMAC) actuators. Detailed structural modeling was conducted to demonstrate deformation similar to that of jellyfish bell. FEM model incorporated hyperelastic behavior of artificial mesoglea (Ecoflex-0010 RTV, room temperature vulcanizing silicone with shore hardness (0010)), experimentally measured SMA temperature transformation, gravity and buoyancy forces. The model uses the actual control cycle that was optimized for driving the artificial jellyfish vehicle "robojelly". Using a comparative analysis approach, fundamental understanding of the jellyfish bell deformation, thrust generation, and mechanical efficiency were provided. Meeting energy needs of artificial vehicle is of prime importance for the UUVs. Some jellyfish species are known to use photosynthesis process indirectly by growing algae on their exumbrella and thereby utilizing the sunlight to generate energy. Inspired by this concept, an extensive model was developed for harvesting solar energy in underwater environment from the jellyfish bell structure. Three different species were modeled for solar energy harvesting, namely A.aurita, C.capillata and Mastigia sp., using the amorphous silicon solar cell and taking into account effect of fineness ratio, bell diameter, turbidity, depth in water and incidence angle. The models shows that in shallow water with low turbidity a large diameter vehicle may actually generate enough energy as required for meeting the demand of low duty cycle propulsion. In future, when the solar energy harvesting technology based upon artificial photosynthesis, referred to as "dye-sensitized solar cells", matures the model presented here can be easily extended to determine its performance in underwater conditions. In order to supplement the energy demand, a novel concept of thermal -- magnetic energy harvesting was developed and extensively modeled. The proposed harvester design allows capturing of even small temperature differences which are difficult for the thermoelectrics.  A systematic step-by-step model of thermo-magnetic energy harvester was presented and validated against the experimental data available in literature. The multi-physics model incorporates heat transfer, magnetostatic forces, mechanical vibrations, interface contact behavior, and piezoelectric based energy converter. We estimated natural frequency of the harvester, operating temperature regimes, and electromechanical efficiency as a function of dimensional and physical variables. The model provided limit cycle operation regimes which can be tuned using physical variables to meet the specific environment. Buoyancy control is used in aquatic animals in order to maintain their vertical trajectory and travel in water column with minimum energy expense. Some crustaceans employ selective ion replacement of heavy or lighter ions in their dorsal carapace. A model of a buoyancy chamber was developed to achieve similar buoyancy control using electro-osmosis. The model captures all the essential ionic transport and electrochemistry to provide practical operating cycle for the buoyancy engine in the ocean environment. / Ph. D.

Electromagnetic transient and dynamic modeling and simulation studies are presented for a StatCom-SMES compensator in power systems. The transient study aims to better understand the transient process and interaction between a high power/high voltage SMES coil and its power electronics interface, dc-dc chopper. The chopper is used to attach the SMES coil to a StatCom. Following the transient study, the integration of a StatCom with SMES was explored to demonstrate the effectiveness of the combined compensator in damping power oscillations. The transient simulation package PSCAD/EMTDC has been used to perform the integrated modeling and simulation studies. A state of the art review of SMES technology was conducted. Its applications in power systems were discussed chronologically. The cost effective and feasible applications of this technology were identified. Incorporation of a SMES coil into an existing StatCom controller is one of the feasible applications, which can provide improved StatCom operation, and therefore much more flexible and controllable power system operation. The SMES coil with the following unique design characteristics of 50MW (96 MW peak), 100 MJ, 24 kV interface has been used in this study. As a consequence of the high power/ high voltage interface, special care needs to be taken with overvoltages that can stress the insulation of the coil. This requires an investigation of transient overvoltages through a detailed modeling of SMES and its power electronics interface. The electrical model for the SMES coil was developed based on geometrical dimensions of the coil. The interaction between the SMES coil and its power electronics interface (dc-dc chopper for the integration to StatCom) was modeled and simulated to identify transient overvoltages. Transient suppression schemes were developed to reduce these overvoltages. Among these are MOV implementation, surge capacitors, different configurations of the dc-dc chopper. The integration of the SMES coil to a StatCom controller was developed, and its dynamic behavior in damping oscillations following a three-phase fault was investigated through a number of simulation case studies. The results showed that the addition of energy storage to a StatCom controller can improve the StatCom-alone operation and can possibly reduce the MVA rating requirement for the StatCom operating alone. The effective location selection of a StatCom-SMES controller in a generic power system is also discussed. / Ph. D.

This dissertation is the result of research and development of a power conditioning system for Superconductive Magnetic Energy Storage System. The dominant challenge of this research was to develop the power conditioning system that can match slowly varying dc voltage and dc current on the super conductive magnet side with the ac voltages and ac currents on the utility side. At the same time the power conditioning system was required to provide a bi-directional power flow to the superconductive magnet. The focus of this dissertation is a three-level diode clamped dc-ac converter which is a principle part of the power conditioning system. Accordingly, this dissertation deals with the space vector modulation of three-level converters and introduces a computationally very efficient three-level space vector modulation algorithm that is experimentally verified. Furthermore, the proposed space vector modulation algorithm is successfully generalized to allow equally efficient, real time implementation of space vector modulation to dc-ac converters with virtually any number of levels. The most important advantage of the proposed concept is in the fact that the number of instructions required to implement the algorithm is almost independent from the number of levels in a multilevel converter. More on the side of the control of multilevel converters, the particular attention in this dissertation is paid to the problem of charge balance in the split dc-link capacitors of three-level neutral-point-clamped converters. It is a known fact that although the charge balance in the neutral point can be maintained on a line cycle level, a significant third harmonic current flows into the neutral point for certain loading conditions, causing the neutral point voltage ripple. The logical consequence of that ripple is the deteriorated quality of the output voltage waveforms as well as the increased voltage stress on the switching devices. This was the motivation to more carefully explore the loading conditions that cause the unbalance, as well as to study the fundamental limitations of dc-link capacitor charge balancing algorithms. As a part of that work, a new model of the neutral point current in the rotating coordinate frame is developed as a tool in investigation of theoretical limitations and in providing some intuitive insight into the problem. Additionally, the low frequency ripple is quantified and guidelines are offered that can help size the dc-link capacitors. Because the study of the neutral point balance identified the loading conditions, that under some possible system constraints, cause an unavoidable neutral point voltage ripple, a feed forward type of control method is developed next. The proposed feed forward algorithm can effectively prevent the neutral point voltage ripple from creating distortions in the converter output voltage under all loading conditions and without causing additional disturbance in the neutral point voltage. The feed forward method is developed for a sine triangle as well as for the space vector type PWM algorithm. The simulation results that include the full dynamic model of the converter and load system validate the feed forward approach and prove that the feed forward algorithm can effectively compensate the effect of the neutral point voltage ripple. The simulation results are than experimentally verified. / Ph. D.

Superconducting Magnetic Energy Storage (SMES) has branched out from its application origins of load leveling, in the early 1970s, to include power quality for utility, industrial, commercial and military applications. It has also shown promise as a power supply for pulsed loads such as electric guns and electromagnetic aircraft launchers (EMAL) as well as for vital loads when power distribution systems are temporarily down. These new applications demand more efficient and compact high performance power electronics. A 250 kW Power Conditioning System (PCS), consisting of a voltage source converter (VSC) and bi-directional two-quadrant DC/DC converter (chopper), was developed at the Center for Power Electronics Systems (CPES) under an ONR funded program. The project was to develop advanced power electronic techniques for SMES Naval applications. This thesis focuses on system analysis and development of a demonstration test plan to illustrate the SMES systems' ability to be multitasked for implementation on naval ships. The demonstration focuses on three applications; power quality, pulsed power and vital loads. An integrated system controller, based on an Altera programmable logic device, was developed to coordinate charge/discharge transitions. The system controller integrated the chopper and VSC controller, configured applicable loads, and dictated sequencing of events during mode transitions. Initial tests with a SMES coil resulted in problems during mode transitions. These problems caused uncontrollable transients and caused protection to trigger and processors to shut down. Accurate models of both the Chopper and VSC were developed and an analysis of these mode transition transients was conducted. Solutions were proposed, simulated and implemented in hardware. Successful operation of the system was achieved and verified with both a low temperature superconductor here at CPES and a high temperature superconductor at The Naval Research Lab. / Master of Science

Superconducting Magnetic Energy Storage (SMES) offers many advantages over conventional forms of energy storage. The higher unit costs of SMES make it economically feasible only for large-scale applications (5000 MWh or more). Early studies showed that low aspect ratio solenoids have the lowest overall costs and most of the subsequent research and conceptual design was centered around low to moderate aspect ratio solenoidal designs. Toroids, poloids and force-reduced magnets are some alternate magnet structures that can be used for SMES but have not received much attention. These structures have some advantages over solenoidal designs such as lower peak fields with greater energy storage capability (poloid), lower support structure requirement (force-reduced magnet) and zero external field (toroid). For some applications of SMES such as pulsed power for fusion reactors or particle accelerators, where the large external field of the solenoid may be unacceptable but the fast response and high efficiency of SMES are required, alternate magnet structures or geometries must be used even if the costs are somewhat higher. Therefore it is useful to study the relative costs of each magnet structure in order to choose a suitable magnet structure for a given application. Four magnet structures viz. the solenoid, toroid, poloid and a force-reduced magnet are evaluated for their energy storage capability, support structure requirements and stray field characteristics. The variation of these parameters with the geometry of the magnet as well as the size of the SMES system are also studied. The objective of this study is to provide a quantitative comparison of important magnet parameters as well as to develop a simple procedure for the preliminary magnetic design of SMES magnets of any size, based on the detailed analysis of a reference design. Due to the high costs of SMES particularly for smaller sizes, it is important to optimize magnet design as well as to look for new magnet configurations to make SMES more cost effective. Superconductor and support structure material are major components of the overall cost of SMES magnets. Various methods of optimizing these parameters are explored. Force-reduced magnets have attracted some controversy in SMES research due to various claims made for and against them. The virial theorem and its implications for force-reduced magnets are analyzed with reference to a specific force-reduced configuration and it is shown that the claims that force-reduced magnets do not offer any savings in structure are unjustified. Methods for further reducing the structure requirements in force-reduced magnets and toroidal magnets are discussed. Due to the unique and highly desirable characteristic of zero stray field of toroidal magnets, it is important to seek ways of increasing its energy storage capability. A variational problem is formulated to determine the optimal cross-sectional shape which maximizes the stored energy with a given quantity of superconductor. The optimal shape stores 16 p.c. more energy than the circular cross section toroid and is shown to be identical to the structurally superior constant tension D shape. The desired characteristics of an ideal SMES magnet are shown to be a uniform magnetic field within a closed magnet configuration. A twisted toroidal magnet combining the features of an ideal solenoid and the general toroidal configuration is studied as a candidate for the ideal magnet. Geometric arguments are used to prove that no such closed surface can be found in three dimensions with the minimum smoothness conditions required from physical considerations. / Ph. D.

Le travail effectué dans cette thèse a pour thème central la conception d’un aimant quadripolaire supraconducteur en Nb-Ti destiné à remplacer à l’horizon 2014 les aimants d’insertions actuellement utilisés dans le grand collisionneur de Hadrons (LHC) du CERN de Genève. Ce nouveau quadripôle, caractérisé par un diamètre d’ouverture encore jamais atteint (120 mm), ouvre la voie vers les quadripôles à grandes ouvertures. Tout d’abord, pour rapidement estimer l’énergie magnétique stockée dans un quadripôle de type cos2?, une formule analytique basée sur la décomposition en série de Fourier du courant et permettant d’estimer l’énergie avec une précision de 10 % est développée. Le design magnétique de la section transverse de la bobine du quadripôle est ensuite réalisé en utilisant une nouvelle méthode d’optimisation basée sur les équations analytiques du champ magnétique. Puis, pour la première fois, une estimation de la reproductibilité dans le positionnement des blocs de conducteurs dans des aimants Nb3Sn est faite. Elle a été réalisée à l’aide d’une méthode existante et grâce à la production récente de deux séries d’aimants Nb3Sn. Une comparaison avec les valeurs obtenues pour des aimants en Nb-Ti est présentée. Ensuite, une méthode analytique basée sur les statistiques et permettant d’expliquer certains phénomènes observés sur la dispersion des mesures magnétiques dans une série de quadripôles est développée. Enfin, on montre que l’incertitude sur la moyenne des harmoniques de champ est due pour la majorité des harmoniques à un phénomène statistique lié au nombre limité d’aimants dans la série et non à des erreurs systématiques / The main objective of the work presented in this thesis is the design of a quadrupole magnet based on Nb-Ti. It aims at replacing the current insertion quadrupoles used in the Large Hadron Collider (LHC) at CERN by 2014. This new quadrupole features an unprecedented large aperture (120 mm) and opens the way toward large aperture quadrupoles. First, to rapidly estimate the magnetic energy stored in a cos2?-type quadrupole, an analytical formula based on the Fourier transform of the current is developed. It allows estimating the energy with a precision of 10 %. Secondly, the magnetic design of the quadrupole coil cross-section is realized using a novel optimization method based on analytical equations of the magnetic field. Subsequently, for the first time, an estimate of the reproducibility in the coil-blocks positioning in Nb3Sn magnets is given. The estimate has been obtained by using an existing method and from tow recently built Nb3Sn magnet series. A comparison with values obtained for Nb-Ti magnets is also presented. Following this, an analytical method based on statistics is developed. It makes possible to explain some phenomenon observed on the dispersion of the magnetic measurement in a quadrupole series. Finally, we show that the uncertainty in the mean of the magnetic field errors is for most of the harmonics related to statistical errors due to the limited number of magnets in the series, and not because of systematic defects in the coil