Dissertationen zum Thema „Active sonar systems“

Detection of an underwater target with active sonar in shallow waters such as the Baltic sea is a big challenge. This since the sound beams from the sonar will be reflected on the surfaces, sea surface and sea bottom, and the water volume itself which generates reverberation. Reverberation which will be reflected back to the receiver, is strong in intensity which give rise to many false targets in terms of classifying a target in a surveillance area. These false targets are unwanted and a real target might benefit from these miss-classifications in terms of remaining undetected. It is especially hard if the signal-to-noise ratio (SNR) is approaching zero, i.e. the target strength and the reverberation strength are equal in magnitude. The classical approach to a target detection problem is to assign a threshold value to the measurement, and the data point exceeding the threshold is classified as a target. This approach does not hold for low levels of SNR, since a threshold would not have a statistical significance and could lead to neglecting important data. Track-before-detect (TrBD) is a proposed method for low-SNR situations which tracks and detects a target based on unthresholded data. TrBD enables tracking and detecting of weak and/or stealthy targets. Due to the issues with target detection in shallow waters, the hypothesis of this thesis is to investigate the possibility to implement TrBD, and evaluate the performance of it, when applied on a low-SNR target. The TrBD is implemented with a particle filter which is a recursive Bayesian solution to the problem of integrated tracking and detection. The reverberation data was generated by filtering white noise with an Autoregressive filter of order 1. The target is assigned to propagate according to a constant velocity state space model. Two types of TrBD algorithms are implemented, one which is trained on the background and one which is not. The untrained TrBD is able to track and detect the target but only for levels of SNR down to 4dB. Lower SNR leads to the algorithm not being able to distinguish the target signal from the reverberation. The trained TrBD on the other hand, is able to perform very well for levels of SNR down to 0dB, it is able to track and detect the target and neglect the reverberation. For trajectories passing through areas with high reverberation, the target was lost for a short period of time until it could be retracked again. Overall, the TrBD was successfully implemented on the self-generated data and has a good performance for various target trajectories.

Thesis: S.M. in Oceanographic Engineering, Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2017.
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science; and the Woods Hole Oceanographic Institution), 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 885-86).
A newly discovered double ducted acoustic environment present throughout much of the Beaufort Sea in the Arctic has a major effect on active acoustic transmissions. This work performs an in depth analysis of how the lower duct impacts the propagation of various active signals used commonly for acoustic communications or active sonar. First, this thesis performs a thorough modal analysis of the effect of the double ducted environment on long range propagation of a 300 Hz and 3500 Hz pulse. Signal excess is determined for the two different source pulses to quantify the effect of the lower duct on noise and SNR. Finally, channel capacity is calculated for the two frequency bands to evaluate operational impacts of the lower duct on acoustic communication systems in the Arctic.
by Scott Adams Carper
S.M. in Oceanographic Engineering
S.M.

A framework that presents a new methodology for design-evaluation of active solar collection systems was developed. Although this methodology emphasizes the importance of detailed modeling for accurate prediction of building performance, it also presents a process through which the detailed modeling results can be reused in a simplified iterative procedure allowing the designer the flexibility of revising and improving the preliminary design. For demonstration purposes, the framework was used to design and evaluate two case studies located in Blacksburg (VA) and Minneapolis (MN). These locations were selected because they both represent a cold weather region; presenting a need for using solar energy for heating and hot water requirements. Moreover, the cold weather in Blacksburg is not as severe as in Minneapolis. Therefore, the two cases will result in different thermal loading structures enabling the framework validation process. The solar collection system supplying both case studies consisted of a low temperature flat plate solar collector and storage system. Thermal performance of the case study located in Blacksburg was conducted using detailed modeling evaluation techniques; while thermal performance of the case study located in Minneapolis was conducted using a simplified modeling evaluation technique. In the first case study, hourly evaluation of the thermal performance of the solar collection system was accomplished using finite element (FE) analysis, while hourly evaluation of the building thermal performance was made using Energy Plus software. The results of the finite element analysis were used to develop a statistical predictive design equation. The energy consumption for the second case study was calculated using the heating design day method and the energy collection for that case study was calculated using the predictive design equation developed from the first case study results. Results showed that, in the case of the building located in Blacksburg, the solar collection system can supply an average of 85% of the buildingâ s heating and hot water requirements through out the year. In the case of the building located in Minneapolis, the solar collection system can supply an average of 56% of the buildingâ s heating and hot water requirements through out the year given no night time window insulation and using similar insulation thicknesses for both cases.
Ph. D.

The domain below the surface in maritime security is hard to monitor with conventional methods, due to the often very noisy environment. In conventional methods the measurements are thresholded in order to distinguish potential targets. This is not always a feasible way of treating measurements. In this thesis a system based on raw measurements, that are not thresholded, is presented in order to track and classify divers with an active sonar. With this system it is possible to detect and track weak targets, even with a signal to noise ratio that often goes below 0 dB.

The system in this thesis can be divided into three parts: the processing of measurements, the association of measurements to targets and the classification of targets. The processing of measurements is based on a particle filter using Track Before Detect (TBD). Two algorithms for association of measurements, Joint Probabilistic Data Association (JPDA) and Highest Probability Data Association (HPDA), have been implemented. The classification of targets is done using an assumed novel approach. The system is evaluated by doing simulations with approximately 8 hours of recorded data, where divers are present at nine different times. The simulations are done a number of times to catch The classification rate is high and the false alarm rate is low.

Undervattensdomänen är svår att övervaka i marina säkerhetssystem med sedvanliga metoder, på grund av den brusiga miljön. I traditionella metoder trösklas mätningarna för att urskilja potentiella mål. Detta är inte alltid ett godtagbart sätt att behandla mätningar på. I den här rapporten presenteras ett system baserat på behandling av rå mätdata, som inte trösklas, för att spåra och klassificera dykare med en aktiv sonar. Med detta system är det möjligt att detektera och spåra svaga mål, trots att signal till brus förhållandet ofta går under 0 dB.

Systemet i den här rapporten kan delas upp i tre delar: behandling av mätningar, association av mätningar till mål samt klassificering av mål. Behandlingen av mätningarna görs med ett partikelfilter som använder Track Before Detect (TBD). Två algoritmer för associering av mätningar, Joint Probabilistic Data Association (JPDA) och Highest Probability Data Association (HPDA), har implementerats. Klassificeringen av mål görs med en egenutvecklad metod som inte har hittats i existerande dokumentation. Systemet utvärderas genom att simuleringar görs på ungefär 8 timmar inspelad data, där dykare är närvarande vid nio olika tillfällen. Simuleringarna görs ett antal gånger för att fånga upp stokastiska beteenden. Andelen lyckade klassificeringar är hög och andelen falsklarm är låg.

Asteroid missions are gaining interest from the scientific community and many new missions are planned. The Didymos binary asteroid is a Near-Earth Object and the target of the Asteroid Impact and Deflection Assessment (AIDA). This joint mission, developed by NASA and ESA, brings the possibility to build one of the first CubeSats for deep space missions: the ASPECT satellite. Navigation systems of a deep space satellite di er greatly from the common planetary missions. Orbital environment close to an asteroid requires a case-by-case analysis. In order to develop the Attitude Determination Control System (ADCS) for the mission, one needs detailed information about orbital disturbances in the vicinity of the asteroid. This work focuses on the development of a simulator that characterises the orbital disturbances a ecting the ASPECT satellite in the space environment near the Didymos asteroid. In this work, a model of orbital conditions and disturbances near the Didymos system was defined. The model integrates several classical and modern models of spacecraft motion and disturbance. An existing Low Earth Orbit (LEO) simulator was modified and updated accordingly to the ASPECT mission scenario. The developed simulator can be used to analyse the disturbances to be counteracted by the ADCS of the ASPECT satellite. The objective of the study was to quantify the e ect of both non-gravitational and gravitational disturbances. The simulator was used to analyse di erent orbit scenarios related to the period of the mission and to the relative distance between the spacecraft and the asteroid system. In every scenario, the solar radiation pressure was found to be the strongest of the disturbance forces. With the developed simulator, suitable spacecraft configurations and control systems can be chosen to mitigate the e ect of the disturbances on the attitude and orbit of the ASPECT satellite.

The aim of this thesis was to investigate and challenge current thinking regarding the sensitivity of the thermal performance of active solar water heating systems to the control strategy employed, with particular attention to the effect of the control temperature differential settings between the solar absorber plate and the solar store at which the circulating pump is switched on and off (dTon and dToff). A mathematical analysis suggested that the performance should be more sensitive to the above parameters than is generally believed. The theoretical appraisal also suggested a relationship for the ratio dTon/dToff required for stable pump control. Measured data from a large-scale solar heating field trial were carefully correlated with the predictions of a computer model. The calibrated model was then used to carry out a sensitivity analysis into the effect of altering the control criteria. The results have shown that, contrary to current thinking, the long-term thermal performance of the system is significantly impaired by the use of a pump switch-on criterion (dTon) higher than 6°K, and that the sensitivity to this parameter increases with increasing dTon. The results have also revealed that the heat losses throughout the system are five or six times higher than theoretical calculations based on the insulation manufacturers' specifications predict. This is not an isolated result, but has been experienced on other monitored installations, and the implication is that the quoted figures for insulation performance (which are derived from tests under tightly controlled laboratory conditions) are extremely difficult to achieve in practice. It is argued that the above two observations are linked, and that a high switch-on criterion leads to significant amounts of collectable solar radiation being wasted as the collector absorber plate loses heat to the surrounding air without reaching a temperature sufficient to turn the circulating pump on. The effect of the control settings on pump switching stability was also investigated, and, whilst the point at which instability occurred did not agree precisely with the theoretical value, the general relationship between the ratio dTon/dToff and the number of pump switching cycles per year supported the mathematical hypothesis. The discrepancy was attributed to the difficulty of measuring the collector overall heat loss coefficient, U1, precisely. For the installation under study it was found that a value of dTon/dToff above 8 would ensure stable pump control. Interpreting optimum performance in terms of both annual solar energy output and pump switching stability, the combination of all the above results led to the general recommendation that a pump switch-on setting of 4-6°K with a switch-off setting of 0.1-0.5°K should be employed to achieve optimum performance of a solar water heating system utilising flat plate solar collectors in the UK. The switch-on criterion of 4-6°K can be achieved reasonably easily by the use of standard, inexpensive controllers and nickel-based temperature sensors. However, such controllers are not capable of consistently resolving temperature differentials to the degree required to meet the switch-off criterion of 0.1-0.5°K over the full operating temperature range. For large installations, therefore, the use of high quality controllers with calibrated platinum resistance thermometers as temperature sensors will prove cost-effective and is strongly recommended.

Due to the rapid growth of grid-tied solar photovoltaic (PV) systems in the generation mix, the distribution grid will face complex operational challenges. High PV penetration can create overvoltages and voltage fluctuations in the network, which are major concerns for the grid operator. Traditional voltage control devices like switched capacitor banks or line voltage regulators can alleviate slow-moving fluctuations, but these devices need to operate more frequently than usual when PV generation fluctuates due to fast cloud movements. Such frequent operations will impact the life expectancy of these voltage control devices. Advanced PV inverter functionalities enable solar PV systems to provide reliable grid support through controlled real injection and/or reactive power compensation. This dissertation proposes a voltage regulation technique to mitigate probable impacts of high PV penetrations on the distribution voltage profile using smart inverter functionalities. A droop-based reactive power compensation method with active power curtailment is proposed, which uses the local voltage regulation at the inverter end. This technique is further augmented with very short-term PV generation forecasts. A hybrid forecasting algorithm is proposed here which is based on measurement-dependent dynamic modeling of PV systems using the Kalman Filter theory. Physical modeling of the PV system is utilized by this forecasting algorithm. Because of the rise in distributed PV systems, modeling of geographic dispersion is also addressed under PV system modeling. The proposed voltage regulation method is coordinated with existing voltage regulator operations to reduce required number of tap-change operations. Control settings of the voltage regulators are adjusted to achieve minimal number of tap-change operations within a predefined time window. Finally, integration of energy storage is studied to highlight the value of the proposed voltage regulation technique vis-à-vis increased solar energy use.
Ph. D.

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The existence of a highly reliable prediction system to detect the occurrence of large solar flares (class X) is still an unsolved problem. Despite many studies performed so far, no such a system has been found yet. In this work, we have developed a method using Bayesian Network - an Artificial Intelligence technique for the detection of giant solar flares. The Bayesian Networks software learned the relation among the variables that describe the sunspots within an active region and built a network with the relationships among them based on conditional probabilities. The studies were divided into two stages one to detect whether the sunspot would produce a big flare or not and another phase where some networks were built to discover the day the flare would occur. The first phase results were very satisfactory reaching a reliability of 77%. The second phase was more complex and the results were about 77% (with day constraints) and 54% (a wider range of days).
A existência de um sistema de previsão, de alta confiabilidade, para a detecção de ocorrência de grandes explosões solares (classe X) ainda é um problema sem solução. Existem diversos estudos nesta área, porém ainda não foi encontrado nenhum sistema eficiente. Para este trabalho foi desenvolvido um método utilizando-se redes Bayesianas, técnica de Inteligência Artificial, para a previsão das grandes flares (explosões) solares. O software de redes Bayesianas aprendeu a relação entre as variáveis que descrevem as regiões ativas e constroem uma rede com os relacionamentos entre elas baseados em probabilidades condicionais. Os estudos foram divididos em duas etapas, uma rede para detectar se a mancha solar irá produzir uma grande explosão ou não, e uma outra etapa em que foram construídas redes para prever o dia em que a explosão irá ocorrer. Os resultados obtidos na primeira etapa foram bem satisfatórios, atingindo 84% de confiabilidade. Já a segunda etapa do trabalho mostrou-se mais complexa e os resultados obtidos foram de 77% (com restrições de dias) e 54% (sem restrições de dia).

Les marges continentales, passives ou actives, sont la principale voie de transfert sédimentaire entre le plateau continental et le bassin océanique profond et les plaines abyssales. Les pentes continentales sont le siège de processus d'érosion/dépôt sous le contrôle de transfert de flux particulaires continentaux chenalisés par des structures érosives, telles que les canyons sous‐marins, puis redistribues à l'ensemble de la marge. Les canyons érodent fortement les pentes continentales et contribuent à l'évolution de leur morphologie au cours du temps. On retrouve cependant des canyons sous‐marins qui ne sont pas en relation avec la présence d'un réseau fluviatile. De ce fait, la formation et l'évolution des canyons sous‐marins sont encore peu comprises. Ce travail de thèse s'intéresse aux processus de formation et d'évolution de six canyons sous-marins sur la Marge Ouest du Bassin Ligure et à dix systèmes de canyons sur la Marge Calabro-Ionienne. Le but de cette étude est de contraindre les principales caractéristiques morphométriques (longueur, largeur, profondeur, inclinaison, sinuosité), morphologique (éléments architecturaux, configuration) des canyons, de caractériser leur évolution amont‐aval et d'analyser leur structure interne, afin de mieux comprendre l'origine des canyons sous‐marins, leurs mécanismes de construction et leur évolution au cours du temps en relation avec le contexte géologique régional et leurs potentiels bassins versants subaérien. Pour cela, une approche basée sur une analyse morpho-bathymétrique et géophysiques a été mise en œuvre à partir de relevés bathymétriques complets des marges, de profils de sismiques, de Chirp et de SAR.

Attempts to reduce greenhouse gas emissions are promising with the recent dramatic increase of installed renewable energy sources (RES) capacity. Integration of large intermittent renewable resources affects smart grid systems in several significant ways, such as transient and voltage stability, existing protection scheme, and power leveling and energy balancing. To protect the grid from threats related to these issues, utilities impose rigorous technical requirements, more importantly, focusing on fault ride through requirements and active/reactive power responses following disturbances. This dissertation is aimed at developing and verifying the advanced and algorithmic methods for specification of protection schemes, reactive power capability and power control requirements for interconnection of the RESs to the smart grid systems. The first findings of this dissertation verified that the integration of large RESs become more promising from the energy-saving, and downsizing perspective by introducing a resistive superconducting fault current limiter (SFCL) as a self-healing equipment. The proposed SFCL decreased the activation of the conventional control scheme for the wind power plant (WPP), such as dc braking chopper and fast pitch angle control systems, thereby increased the reliability of the system. A static synchronous compensator (STATCOM) has been proposed to assist with the uninterrupted operation of the doubly-fed induction generators (DFIGs)-based WTs during grid disturbances. The key motivation of this study was to design a new computational intelligence technique based on a multi-objective optimization problem (MOP), for the online coordinated reactive power control between the DFIG and the STATCOM in order to improve the low voltage ride-through (LVRT) capability of the WT during the fault, and to smooth low-frequency oscillations of the active power during the recovery. Furthermore, the application of a three-phase single-stage module-integrated converter (MIC) incorporated into a grid-tied photovoltaic (PV) system was investigated in this dissertation. A new current control scheme based on multivariable PI controller, with a faster dynamic and superior axis decoupling capability compared with the conventional PI control method, was developed and experimentally evaluated for three-phase PV MIC system. Finally, a study was conducted based on the framework of stochastic game theory to enable a power system to dynamically survive concurrent severe multi-failure events, before such failures turn into a full blown cascading failure. This effort provides reliable strategies in the form of insightful guidelines on how to deploy limited budgets for protecting critical components of the smart grid systems.

The aim of the thesis is to model energetic needs for heating and temperatures progress in the building with almost zero energy consumption. The part of the work is the economical and energetic comparison. Proposed systems are based on a knowledge of active houses.

Despite recent advances in the global electrification rates, increasing from 76% in 1990 to 85% in 2012, the United Nations goal of universal access to electricity by 2030 is still far from achieved, with an estimated 1.1 billion people still without access to electricity. Over half of these live in Sub-Saharan Africa, with a majority in rural areas and extreme poverty. Major challenges are inert with the current electrification path of centralized grid extension, leaving these people without power in decades to come. Microgrids, a decentralized power system consisting of solar power generation, energy storage and distribution technology, has been hailed as the only option to provide life improving and productivity inducing power for rural communities in Africa. However, despite recent hype and development in the sector, the diffusion of microgrids is still incremental due to a lack of viable large-scale operation, required for profitability. This is explained by targeting customers in remote rural areas with low ability to pay, and the task of delivering expensive technology and complex operations needed to manage and operate the grids. No industry blueprint or research on how to operate microgrids at scale or profitably exists. This thesis explores one blueprint, with the promise to increase profitability and allow for a more sustainable scaling. Local Capacity building is a decentralized approach by developing capacity directly in the local communities, through recruiting, skills development and training of people to be employed to operate and manage their local microgrids. The results consist of a framework outlining what local capacity building is, through research propositions that define the key components capturing the complete system of local capacity building is for scaling a microgrid business, along with the challenges and opportunities associated with scaling a business using local capacity building. It has been developed iteratively by application of an action research approach conducted on a small-scale Zambian Microgrid company facing radical growth. The researcher was immersed in the context, at the heart of this change, and in a participatory and interventionist fashion turning every stone to explore what local capacity building is, resulting in a robust study anchored in the field. Because of the contextually embedded nature of the data, this also means that the results are local. It is up to the reader to assess the applicability of the results in another context. The extensive results span multiple areas of the business, capturing the complexity of local capacity building, and contribute to knowledge on a holistic level on what local capacity building is. This blueprint was deemed viable to further develop in the small-scale Zambian microgrid company, specifically because of its potential to lower operating expenses and offer a more sustainable way to scale, and in extension diffuse microgrids in Africa.
Trots en positiv utveckling i tillgång till el globalt, ökandes från 76% år 1990, till 85% år 2012, så är Förenta Nationernas mål om universell tillgång till el till år 2030, långt ifrån att bli uppfyllt. 1.1 miljarder människor estimeras vara utan tillgång till el globalt, där över hälften av dessa bor i Sub-Saharanska Afrika, med majoriteten levandes på landsbygden och i extrem fattigdom. Stora utmaningar finns med innevarande elektrifierings strategin, som handlar om centraliserad elproduktion och distribution genom ett centralt elnät, detta kommer att lämna dessa människor utan el under lång tid framöver. Mikronät, ett decentraliserat energisystem, som kan producera och distribuera el, har lyfts fram som det bästa alternativet för att försörja livsförbättrande och produktivitetsökande elektricitet för samhällen på landsbygden i Afrika. Dock, trots nylig hype och utveckling i mikronät sektorn, så är spridningen av mikronät fortfarande inkrementell, beroende av en brist på genomförbarheten av att driva mikronät verksamheten i stor skala, vilket krävs för lönsamhet. Detta förklaras av den fundamentala utmaningen i att inrikta sig mot kunder i avlägsna områden, med en låg förmåga att betala, kombinerat med leveransen av dyr teknologi, och de komplex operativa strukturerna som krävs. Det finns ingen forskning eller blåkopia i industrin som visar hur man skulle kunna bedriva mikronäts verksamhets i stor skala, eller på ett lönsamt vis. Denna forskning undersöker en möjlig sådan blåkopia, med löftet att öka lönsamheten och möjliggöra en mer hållbar spridning. Utveckling av lokal kapacitet, är ett decentraliserat tillvägagångssätt för att utveckla kapacitet direkt i dessa avlägsna samhällen, genom rekrytering, färdighetsutveckling och utbildning av människor för att bli anställda för att sköta deras lokala mikronät. Resultaten i studien består av ett ramverk som visar vad utveckling av lokal kapacitet innebär, genom forskningsförslag som definierar vilka nyckelkomponenter som krävs för att skala upp en mikronäts verksamhet, tillsammans med utmaningar och möjligheter för att göra detta. Ramverket har utvecklats iterativt genom applicering av Action Research, utförd i ett småskaligt mikronät företag i Zambia som står inför en radikal expansion. Forskaren var fördjupad i företagskontexten, i hjärtat av förändringen, och på ett ingripande och deltagande sätt vänt på varenda sten för att utforska vad utveckling av lokal kapacitet är. Detta resulterade i en robust studie, förankrad i verkligheten. På grund av den kontextuellt inbäddade naturen av datan, så betyder detta även att resultaten är lokala. Det är upp till läsaren att bedöma till vilken grad resultaten kan appliceras i en annan kontext. De omfattande resultaten spänner över många olika områden i företaget, och lyckas fånga komplexiteten i vad utveckling av lokal kapacitet är. Blåkopian som utvecklades, bedömdes värdefull att utveckla vidare i företaget där studien gjorde, specifikt för dess potential att minska de operativa kostnaderna och erbjuda ett mer hållbart sätt att skala verksamheten, och i förlängningen, erbjuda ett mer hållbart sätt att sprida tillgång till el i Afrika.

Tracking multiple targets in a high cluttered environment where multiple receivers are used is a challenging task due to the high level of false alarms and uncertainty in the track hypothesis. The multi-static active sonar scenario is an example for such systems where multiple source-receiver combinations are deployed. Due to the nature of the underwater environment and sound propagation characteristics, tracking targets in the underwater environment becomes a complex operation. Conventional tracking approaches (such as the Kalman and particle filter) require a predetermined kinematic model of the target. Moreover, tracking an unknown and changing number of targets within a certain search area requires complex mathematical association filters to identify the number of targets and associate measurements to different target tracks. As the number of false detections increases, the computational complexity of conventional tracking system grows introducing further challenges for real-time target tracking situations. The methodology presented in this thesis provides a rapid and reliable tracking system capable of tracking multiple targets without depending on a kinematic model of the target movement. In this algorithm, Self Organizing Maps, Dynamic Programming and the Hough transform are combined to produce tracks of possible targets’ paths and estimate of targets’ locations. Evaluation of the performance of the tracking algorithm is performed using three types of simulations and a set of real data obtained from a sea trial. This research documents the results of experimental testing and analysis of the tracking system.
Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-08-07 13:21:06.869

碩士
國立中山大學
海下科技研究所
106
Harbor defense has always been a topic of great concern to many countries and the direction of development. In this paper, an underwater listening array system will be integrated to detect underwater targets in Kaohsiung Harbor. Include： 1. Hardware integration (analog to digital recorder, 4 underwater microphones, power supply wiring) 2. Signal design (linear frequency modulation signal) 3. Power supply configuration (lithium battery *4) 4. Signal processing technology In order to correctness of array system, the measurement experiment in May and June 2017, and the test site was near Ryukyu. The calibration experiments were performed on the system to test the correctness of the system. After completing the system test, return to Kaohsiung Port for passive and active acoustic experiments. In the passive experiment, understand the voiceprint of different targets in the harbor and the frequency band of Kaohsiung Harbor noise. In the active experiment, the self-transmission and acoustic experiments are performed, and the signals are transmitted to the underwater target, and the echo is received through the array to detect it. The experimental results show that the underwater listening array system integrated in this study can detect underwater targets through active sonar. When the target is reached, the system will not receive the echo of the target due to the boundary effect. Therefore, in this paper, the solution to the target echo in the harbor environment will be discussed, and the method will be applied to Kaohsiung Port.

碩士
中華科技大學
電子工程研究所碩士班
98
In this paper, solar tracking device to control the sun azimuth and elevation control formula and use Matlab/Simulink simulation software to control the directionality of solar panels. Body in a simulated experiment to track the sun position of celestial bodies accuracy and controller design, as the direction of the study. The solar tracker to accurately track the sun, running, generally divided into two kinds of active and passive: passive relying on optical sensor (light-sensitive resistor) is used for sensing the location of the sun the moment, such as sunflower-like plant phototropism of to move, depending on the precision of optical sensors; active path is calculated after the sun by built-in database to track the sun's position, its accuracy depends on the body. The tracking control system programming with Matlab / Simulink simulation written by Matlab / Simulink simulation platform control interface controller, making the overall operation of an organization, and finally man-machine interface with software written to display relevant of time, azimuth and elevation, and tracking platform to control the attitude angles, the simulated and actual tracking error.

碩士
聖約翰科技大學
電機工程系碩士班
106
This paper is to develop a real-time sun tracking system with MPPT to improve the electrical efficiency of PV. In the system, the time driven biaxial tracking system is made with PIC16F883 single-chip. The main purpose of the time driven biaxial tracking system is to increase the electrical efficiency of the traditional fixed PV. The core reason why PIC single chip is used as the time driven biaxial tracking system is that the position and angle of the solar light can be calculated quickly and accurately. It is for the purpose of PV can get gabundant sunshine. At the same time, the MPPT controller is used to match the internal resistance of PV to adjust the terminal voltage, so that PV can get good electrical efficiency under different accumulative insolation and temperature conditions. The results of the experiments in this paper will be compared and analyzed.

Thesis (M.S.)--University of Wisconsin--Madison, 1987.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 165-166).

碩士
中原大學
電機工程研究所
95
In a grid-connected solar photovoltaic (PV) system, as grid is disconnected from the solar PV system, if the disconnection is not detected and the PV system operated independently, it is called “islanding operation”. The detection methods can be categorized into passive and active approaches. The passive detection approaches suffer from the existence of un-detection zone (UDZ). Also, exist the issues of active approaches with high cost, power losses, and un-detection zone in the detection process. Therefore, to improve the UDZ drawbacks of the existing active Slip-Mode Frequency Shift (SMS) method, a nonlinear jumping SMS scheme is proposed in the thesis. In the proposed scheme, more perturbation is introduced to the shifting angel, as the stable operating point is approached in the existing SMS method. The time needed by the SMS method around the stable operating point can also be reduced via the proposed scheme. To verify feasibility of the proposed islanding detection scheme, the islanding operating models are established to investigate the detection performance of the proposed scheme and existing SMS method around the stable operating point via the simulations in Matlab. In the simulation tests, the environment with various power quality events is included for verification of the proposed islanding detection scheme. In practical experiments, employed is a current-control voltage source inverter with the core of a digital signal processor (DSP) where the islanding detection capabilities are built. The experimental results the detection performance and UDZ of the traditional SMS method are improved by the proposed scheme. It is proved that the proposed detection scheme can still detect the islanding operation around the stable operating point.

碩士
國立臺北科技大學
冷凍空調工程系所
100
With the increasing awareness of sustainable and green building, more and more people are concerned with the efficiency of energy use at home and at work. A solar tracking skylight illumination system, which enables us to conserve energy by producing increased interior light levels for a longer duration than normally possible, can fit to the above need and have widen been used in the indoor illumination gradually. Tracking sunlight and guide the light indoor as a source of illumination is also a way of energy saving. Daylight catching system, simply put, the light is sunlight, a part of interior when the illumination used; another part of the light is converted to electricity for use. In the self-sufficiency is no need for other power supply, to achieve zero CO2 emissions, a green energy product. Purpose of this study to implement is a way to develop a daylight catching system for illumination. An experimentally investigation is conducted to explore the dynamic illuminative performance of daylight catching system. The daylight catching system drives the sun tracking mechanism by the database of sun-path which is burned in microcontroller. The system will keep working without weather condition. The results show that (1) the triple reflected sunlight can provide sufficient 400~700 Lux to the room from AM 7:00 to PM17:00 without artificial light. (2) The system can be installed not only on the roof of the building, but also on other floors. Mirrors with high reflectivity are used to guide sunlight into the room. So the system can decrease the power consumption of indoor illumination in daytime. (3) With active tracking system, the mechanism can have the best accuracy immediately. The error angle of the mechanism can be less than 2∘. (4)The performance of the system can be seemed as a 27W lamp. The sunshine duration in Taipei (1999~2008) is 1431 hours per year. It means that the system can save 38 kWh per year.

碩士
中華科技大學
電子工程研究所碩士班
99
Abstract This article is to design, through NI LabVIEW software, the controlling dual-axis solar tracking platform, to enable the platform to automatically track the sun so as to obtain the utmost sunlight energy. Based on the earth orbiting from the sun formula, it will automatically calculate the sun rays to the local horizontal elevation and azimuth information, feed into the tracking platform for control systems, and command the control systems to present the required elevation and azimuth patterns. In the research project, we will design a dual-axis to the push-pull control tracking platform and use the linear actuator (Linear Actuator) to push solar panels, which will result in angle change. The Data Acquisition (DAQ) interface will collect displacement volume; through the LabVIEW control program, it will calculate the driving command, send from the DAQ interface to the linear actuator driver (Driver), impel the platform mechanism, and form an automatic control device in order to achieve the purpose of automatic tracking. This system has been verified through actual operation. The overall structure of hardware and software is feasible. Before the tracking system going to work, we implement a set of 2 axis Accelerometer Module (ADXL 203EB) to control and monitor the solar panel leveling in order to establish the platform initial conditions. Key Words: LabVIEW, ON-OFF Driver, Linear Actuator, Data Acquisition, Solar Tracker, Push-Pull Control Tracking Platform, 2 Axis Accelerometer

This thesis presents a methodology developed to identify a parametric model of a thermally-activated building system (TABS) using a system identification (SI) tool. The model was identified with collected data from an energy efficient solar single-family residential building, the Ecoterra™ house located in Eastman, Quebec. The TABS is a ventilated concrete slab (VCS) serving as an energy storage medium for active and passive solar gains in the basement. The system uses the structural mass of the house to store active solar gains collected by the building-integrated photovoltaic/thermal (BIPV/T) roof and passive solar gains entering the living space through the energy efficient windows. A data-driven system identification approach is used. Identifying a linear model and obtaining a low-order polynomial model were the main identification criteria. The thesis addresses the issues of the monitoring sensor accuracy on the model parameters, how physical knowledge of the VCS dynamic system can be considered during its validation and how the identification assumptions guide the future use of the model. This thesis also demonstrates that the identified linear polynomial model is an efficient tool to carry out redesign studies and possible control studies. Improved BIPV/T roof designs are compared based on increased solar energy utilization potential and potential increase of collected thermal energy stored into the VCS. The effect of modifying the BIPV/T roof angle and including a glazing section are analyzed and discussed, demonstrating the use of the identified transfer function model of the VCS as a more efficient and quicker alternative to whole building detailed simulations, particularly for comparing design and operation options on a relative basis.

碩士
中原大學
電機工程研究所
96
The objective of this thesis is to develop a grid-connected solar photovoltaic (PV) system with active power filter. For solar cells, the system adopts the dc/dc boost power converter as well as the improved incremental conductance algorithm for to accelerate the maximum power point speed and the chattering phenomena around maximum power points are reduced and reducing power losses. In addition, the bi-directional dc/dc power converter is designed to charge or discharge batteries in order to regulate the power flow between solar cells, grid power and loads so that it can accomplish the management of energy balance control and enhance the reliability of the whole system. Finally, the system adopts the bi-directional dc/ac power converter as well as the improved fixed-frequency hysteresis current-controlled (HCC) PWM control scheme, being able to reduce the current harmonic, and the DC Change into AC supplies load or carry grid. Experimental and simulated results to verify the performance of the proposed system, this thesis changes the load demand, effectiveness of the energy automatic balancing among solar PV, grid power and load is examined.

碩士
中華大學
機械工程學系碩士班
97
This study takes the ventilation into consideration, making the ABE system more tally with the realistic conditions. The new mechanism of heat transfer was proposed. Then the analytic model has to be revised. Analytic solution will be resulted and verified by the numerical solution of CFD. Finally, we found out that no matter when the fan streamline’s distributed, or the PMV, mean age of air will superior than the fan which has not opened when the fan is turned on, and only the temperature distributed is opposite. In addition, the comparative results of numerical simulation and experiment value, when the air blower is opened, type C (the fan opened with without heat sink) temperature, streamline with experiment value of the type are identical. When the fan has not been opened, type B(without fan、Heat Sink), D(without fan、without heat Sink) streamline with experiment value are identical. Besides, consider whether to increase the comparative result of Heat Sink on the TE system or not, contribute to the TE systematic refrigeration, area of heat dissipation causing heat to increase while increasing the Heat Sink on the TE system. But after compare with two, find out that there no temperature profile, air current which increases Heat Sink to distribute in the TE system, comfortable degree, air and age will be superior than having Heat Sink. From the comparison of result which given above, proves that the Ming dynasty printed books research to increase leads the ventilator type wind-driven generator to provide controls one's breathing spatially the source and the electric power and to be auxiliary of power input the ABE system and promotes radiation of efficiency the heat sink, enables to achieve of the thermal equilibrium condition fast inside.

碩士
大同大學
電機工程學系(所)
97
The purpose of this thesis is to design an active solar panel dual-axis suntracking system with maximum power point tracking fuzzy controller. The tracking system tracks the maximum solar power point no matter what the environmental condition it is and orients the solar panel toward the Sun to enhance the efficiency of thephotovoltaic generation system. First, the operating points of the PV panel are adjusted by a boost converter. The PV voltage and current are measured in real time, and used to estimate the system parameters in the power-voltage polynomial equation and to identify the maximum power. Meanwhile, four light sensors sense one current respectively, which represent the illumination at the time. Inputting the maximum power and four currents to the two fuzzy controllers for dual-axis tracking system, the rotated angles will be got to make the mechanism rotate to the appropriate position. Through the sun tracking method, the PV panel will face the Sun directly at all time. Finally, the simulation results using Matlab verify the effectiveness of the proposed controller.

博士
國立高雄應用科技大學
機械工程系
106
In this article, a unique concentrated solar tracking system, the electromechanical and open-looped altitude-azimuth biaxial-type without additional power, was developed for solar-thermal applications. This system adopted the Fresnel lens module to concentrate sunlight on a Stirling engine’s heating head while conducting measurements for the temperature profile of the heating head. We also installed solar panels on both sides of the solar tracking system to supply power to the driving motors and reduce the torque needed for mechanism operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results show that the energy obtained from the solar panels and stored in the power storage module was greater than the energy needed for driving the tracking system. Therefore, this system did not require additional energy but could store the surplus energy for further applications. Moreover, it is indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. The gust intensity and cloud amount also influenced the efficiency of the concentrated solar-tracking system. The cloud amount affected the amount of solar energy to the heating head, and the gust intensity influenced the thermal radiation on the heating head. In this experiment, we installed insulative material surrounding the heating head to reduce the loss of thermal energy. Under a sunny environment, the temperature of the heating head reached approximately 900°C. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

碩士
國立高雄師範大學
事業經營學系
106
ABSTRACT This study investigated the determining factors for the adoption of solar power systems by the principals of the elementary and high schools based on Theory of reasoned action and Motivation theory. The principals of the elementary and junior high schools in Gaoping District were selected as the research objects in this study, and a total of 158 valid questionnaires were collected. The statistical analysis was performed using SPSS and SmartPLS software. The results showed that the attitude of the elementary and junior high school principals toward the solar power system will positively affect their behavioral intentions and that the norms of the principals’ subjective perception have a positive impact on attitudes; thus, the motivations are all established.In addition, in terms of the motivations, a principal’s economic reward motive (external motivation) and altruistic motive (intrinsic motivation) will affect his or her attitude toward the solar power system. However, the principal’s reputational and reciprocity motives will not affect his or her attitude. Based on the aforementioned results, this study suggests that manufacturers can advertise various advantages of adopting solar power systems to principals and staffs, including increasing rental income, self-sufficient in terms of power, responding to the environmental policies, solar power being pollution-free and associated safety concerns, to strengthen the principal’s economic reward and altruistic motives. Through the norms of the principles’ subjective perception, the manufacturer can simultaneously enhance the principal’s positive attitude toward the solar power system to reinforce their intentions..

Dissertação mestrado em Engenharia Eletrónica Industrial e Computadores
Atualmente, a utilização de cargas não lineares na indústria e nos consumidores gerais é cada vez mais frequente. Este tipo de cargas contribui para acentuar problemas de qualidade de energia elétrica (QEE), resultando em várias consequências, como falhas em equipamentos eletrónicos e subsequente perda de eficiência e envelhecimento prematuro desses dispositivos, podendo causar perdas e prejuízos elevados. Dos problemas de QEE, destacam-se: distorção harmónica nas tensões e/ou correntes, ruído eletromagnético, inter-harmónicos, interrupções de energia elétrica, subtensão (sag), sobretensão (swell), flutuação da tensão (flicker), transitórios e corrente elevada no neutro. Devido aos problemas que advêm da QEE, torna-se necessário desenvolver mecanismos com vista a evitar ou minimizar tais problemas. Uma das soluções para lidar com alguns destes problemas é a utilização de filtros ativos paralelos (FAPs), dado que permitem compensar dinamicamente a distorção harmónica da corrente da instalação elétrica, o fator de potência e desequilíbrios de corrente (no caso de sistemas e FAPs trifásicos). Para além disto, os FAPs também podem ser utilizados simultaneamente para interface com energias renováveis (ERs) e com sistemas de armazenamento de energia (SAEs), funcionando como inversor, tendo assim a possibilidade de injetar energia na rede elétrica com corrente sinusoidal (baixo conteúdo harmónico) e em oposição de fase com a tensão da rede elétrica. É importante ressalvar que mesmo que não haja energia produzida pela fonte de ER, o FAP continua a compensar os problemas de QEE descritos acima. Neste sentido, o cerne desta dissertação de mestrado é implementar um conversor unificado que permita efetuar a ligação de painéis solares fotovoltaicos (PSFs) e de baterias com a rede elétrica e dotar o equipamento com características de operação como FAP. Este processo, vai implicar também o estudo de quais são os algoritmos de controlo mais adequados para extrair a máxima potência dos PSFs, para a operação como FAP e para a operação de carregamento e descarregamento das baterias. Esta série de implementações será previamente validada, através da realização de simulações na ferramenta PSIM e posteriormente através de uma validação experimental.
Currently, the use of non-linear loads in industry and in general consumers is becoming more frequent. This type of loads contributes to accentuate the electric power quality (EPQ) problems, resulting in several consequences, such as faults in electronic equipment (and subsequent loss of efficiency and premature aging of these devices), causing losses and a high damage. Among the EPQ problems, the following stand out: harmonic distortion in the voltages and/or currents, electromagnetic noise, inter-harmonics, electric power outages, undervoltage (sag), overvoltage (swell), voltage fluctuations (flicker), transients and high current in neutral. Due to the problems arising from EPQ, it is necessary to develop mechanisms to prevent or minimize such problems. One of the solutions to deal with some of these problems is the use of parallel active filters (PAFs), as they allow to dynamically compensate the current harmonic distortion of the electrical system, the power factor and current unbalances (in the case of three-phase systems and three-phase PAFs). In addition, the PAFs can also be used simultaneously to do the interface with renewable energies (REs) and with energy storage systems (ESSs), working as an inverter, thus allowing the possibility to inject energy into the grid with sinusoidal current (low harmonic content) and in phase with the electric grid voltage. It is important to note that even if there is no electricity generated by the RE source, the PAF continues to compensate the EPQ problems described above. In this sense, the core of this master’s dissertation is to implement a unified converter that allows the connection of photovoltaic solar panels and batteries with the power grid and provide the equipment with operation characteristics as a PAF. This process will also involve the study of which are the most appropriate control algorithms to extract the maximum power from photovoltaic solar panels, for the operation as a PAF and for the operation of charging and discharging of batteries. This series of implementations will be previously validated through simulations in PSIM tool and subsequently through an experimental validation.
Fundação para a Ciência e Tecnologia (FCT) - Suporte financeiro concedido através do Projeto 0302836 NORTE-01-0145-FEDER-030283 e ERDF–COMPETE 2020 Programme, SAICTPAC/0004/2015–POCI–01–0145–FEDER–016434