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Статті в журналах з теми "Limited power point tracking":
1
KAYIŞLI, Korhan, and Ruhi Zafer CAGLAYAN. "Twisting Sliding Mode Control based Maximum Power Point Tracking." Balkan Journal of Electrical and Computer Engineering 10, no. 4 (October 1, 2022): 356–62. http://dx.doi.org/10.17694/bajece.1137170.
Анотація:
For a world where energy demand is increasing day by day, available resources are constantly decreasing. At this point, it is very important to be able to benefit from the sun, which is the main energy source, with minimum damage to the environment. It is possible to produce electricity directly from sunlight through PV panels. Due to the limited efficiency of these panels, MPPT algorithms are always required. In this study, Sliding Mode Control (SMC) based Twisting Sliding Mode Control (T-SMC) MPPT, known for its robust structure, was performed and the results were compared with the classical SMC. The proposed MPPT algorithm is simulated with MATLAB/Simulink. The efficiency of T-SMC based MPPT is obtained as nearly 99%.
2
Srinivas, Paruchuri, and P. Swapna. "Maximum Power Point Tracking Algorithm for Advanced Photovoltaic Systems." International Journal on Recent and Innovation Trends in Computing and Communication 10, no. 9 (September 30, 2022): 26–39. http://dx.doi.org/10.17762/ijritcc.v10i9.5748.
Анотація:
Photovoltaic (PV) systems are the major nonconventional sources for power generation for present power strategy. The power of PV system has rapid increase because of its unpolluted, less noise and limited maintenance. But whole PV system has two main disadvantages drawbacks, that is, the power generation of it is quite low and the output power is nonlinear, which is influenced by climatic conditions, namely environmental temperature and the solar irradiation. The natural limiting factor is that PV potential in respect of temperature and irradiation has nonlinear output behavior. An automated power tracking method, for example, maximum power point tracking (MPPT), is necessarily applied to improve the power generation of PV systems. The MPPT methods undergo serious challenges when the PV system is under partial shade condition because PV shows several peaks in power. Hence, the exploration method might easily be misguided and might trapped to the local maxima. Therefore, a reasonable exploratory method must be constructed, which has to determine the global maxima for PV of shaded partially. The traditional approaches namely constant voltage tracking (CVT), perturb and observe (P&O), hill climbing (HC), Incremental Conductance (INC), and fractional open circuit voltage (FOCV) methods, indeed some of their improved types, are quite incompetent in tracking the global MPP (GMPP). Traditional techniques and soft computing-based bio-inspired and nature-inspired algorithms applied to MPPT were reviewed to explore the possibility for research while optimizing the PV system with global maximum output power under partially shading conditions. This paper is aimed to review, compare, and analyze almost all the techniques that implemented so far. Further this paper provides adequate details about algorithms that focuses to derive improved MPPT under non-uniform irradiation. Each algorithm got merits and demerits of its own with respect to the converging speed, computing time, complexity of coding, hardware suitability, stability and so on.
3
Maimun, Maimun, and Subhan Subhan. "Different Techniques of Multiple Power Point Tracking for Photovoltaic Systems." Jurnal Litek : Jurnal Listrik Telekomunikasi Elektronika 19, no. 1 (April 4, 2022): 24. http://dx.doi.org/10.30811/litek.v19i1.2887.
Анотація:
Understanding in such way the maximum available power generated by the photovoltaic (PV) array varies with the weather is critical for improving system efficiency by encouraging the PV system to operate at that maximum power point (MPP). Therefore, to maintain optimum power functioning at all irradiance levels and temperatures, a Maximum Power Point Tracking (MPPT) system is necessary. MPPT methods have been developed and implemented in a number of studies. The accuracy, convergence speed, ease of hardware implementation, PV dependency, number of necessary sensors, which are significantly differ across these systems. The first technique to be introduced was a single MPPT technique. However, as it works independently, it was unable to achieve several of the required characteristics. Afterwards, the merger techniques of multiple MPPTs and the combination of both (single and multiple MPPTs’ techniques) due to integrate the benefits of each algorithm while removing their limitations. Comparing and surveying MPPT algorithms in general took a significant amount of time. Despite this, there is a limited literature examining the combination techniques towards the multiple MPPT techniques and the single one. This paper presents the work and uses MATLAB/Simulink platform to simulate it. It is based on a study that contrasts single MPPT techniques with different combinations, namely the constant voltage (CV) method, the perturb and observe (PO) method and the combination of both (CV+PO), in order to validate MPPT's better performance.
4
Maimun, Maimun, and Subhan Subhan. "Different Techniques of Multiple Power Point Tracking for Photovoltaic Systems." Jurnal Litek : Jurnal Listrik Telekomunikasi Elektronika 19, no. 1 (April 4, 2022): 24. http://dx.doi.org/10.30811/litek.v19i1.2887.
Анотація:
Understanding in such way the maximum available power generated by the photovoltaic (PV) array varies with the weather is critical for improving system efficiency by encouraging the PV system to operate at that maximum power point (MPP). Therefore, to maintain optimum power functioning at all irradiance levels and temperatures, a Maximum Power Point Tracking (MPPT) system is necessary. MPPT methods have been developed and implemented in a number of studies. The accuracy, convergence speed, ease of hardware implementation, PV dependency, number of necessary sensors, which are significantly differ across these systems. The first technique to be introduced was a single MPPT technique. However, as it works independently, it was unable to achieve several of the required characteristics. Afterwards, the merger techniques of multiple MPPTs and the combination of both (single and multiple MPPTs’ techniques) due to integrate the benefits of each algorithm while removing their limitations. Comparing and surveying MPPT algorithms in general took a significant amount of time. Despite this, there is a limited literature examining the combination techniques towards the multiple MPPT techniques and the single one. This paper presents the work and uses MATLAB/Simulink platform to simulate it. It is based on a study that contrasts single MPPT techniques with different combinations, namely the constant voltage (CV) method, the perturb and observe (PO) method and the combination of both (CV+PO), in order to validate MPPT's better performance.
5
Abo-Sennah, M. A., M. A. El-Dabah, and Ahmed El-Biomey Mansour. "Maximum power point tracking techniques for photovoltaic systems: a comparative study." International Journal of Electrical and Computer Engineering (IJECE) 11, no. 1 (February 1, 2021): 57. http://dx.doi.org/10.11591/ijece.v11i1.pp57-73.
Анотація:
Photovoltaic systems (PV) are one of the most important renewable energy resources (RER). It has limited energy efficiency leading to increasing the number of PV units required for certain input power i.e. to higher initial cost. To overcome this problem, maximum power point tracking (MPPT) controllers are used. This work introduces a comparative study of seven MPPT classical, artificial intelligence (AI), and bio-inspired (BI) techniques: perturb and observe (P&O), modified perturb and observe (M-P&O), incremental conductance (INC), fuzzy logic controller (FLC), artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and cuckoo search (CS). Under the same climatic conditions, a comparison between these techniques in view of some criteria’s: efficiencies, tracking response, implementation cost, and others, will be performed. Simulation results, obtained using MATLAB/SIMULINK program, show that the MPPT techniques improve the lowest efficiency resulted without control. ANFIS is the highest efficiency, but it requires more sensors. CS and ANN produce the best performance, but CS provided significant advantages over others in view of low implementation cost, and fast computing time. P&O has the highest oscillation, but this drawback is eliminated using M-P&O. FLC has the longest computing time due to software complexity, but INC has the longest tracking time.
6
Aourir, Jamila, and Fabrice Locment. "Limited Power Point Tracking for a Small-Scale Wind Turbine Intended to Be Integrated in a DC Microgrid." Applied Sciences 10, no. 22 (November 12, 2020): 8030. http://dx.doi.org/10.3390/app10228030.
Анотація:
Limited power point tracking (LPPT) is emerging as a new technology for power management controllers for small-scale wind turbines (SSWTs) thanks to its advantages in terms of operation flexibility, economy and system security. LPPT operates in such a way that power requested by the user can be extracted from the wind turbine while respecting constraints. However, operating in LPPT mode still requires a deep understanding to obtain a compromise between minimizing power oscillations and transient response. For that, three LPPT power control strategies for an SSWT intended to be integrated in a direct current (DC) urban microgrid are investigated. These methods concern perturb and observe (P&O) with fixed step size, P&O based on Newton’s method and P&O based on the fuzzy logic (FL) technique. The experimental results highlight that all methods function correctly and reach the limited power point (LPP). The FL method improves dynamic performances with more steady oscillations around LPP compared to fixed step size and Newton’s methods. The sudden variation of wind velocity and power lead us to conclude that the FL method ensures a good balance between reducing oscillation of wind turbine (WT) output power around the operating point and convergence of rising time toward LPP.
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Kozalakis, Konstantinos, Ioannis Sofianidis, Vasileios Konstantakos, Kostas Siozios, and Stylianos Siskos. "73.5 uW Indoor-Outdoor Light Harvesting System with Global Maximum Power Point Tracking." Journal of Low Power Electronics and Applications 11, no. 1 (February 14, 2021): 10. http://dx.doi.org/10.3390/jlpea11010010.
Анотація:
This work introduces a light harvesting system with battery management. In contrast to relevant solutions that operate in limited ranges, the proposed system covers a wide operating input power range from 10 uW up to 300 mW. Specifically, experimental results highlight that, combined with a 73 × 94 mm flexible light harvester, it can harness light in a range from 50 LUX (indoor lighting) up to 120,000 LUX (outdoor lighting). The introduced system consists of a boost converter and an ultra-low power microcontroller (MCU). The MCU performs Global Maximum Power Point Tracking (GMPPT), using a resistor-free time-based input power sensing method, to calculate the input power of the converter, which does not interfere with the operation of the boost converter. The efficiency of the GMPPT system was evaluated with detailed experimentation, where we achieved 99.75% average GMPPT tracking efficiency while consuming only 73.5 uW at 4.2 V.
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Mr. Amol Barve, Mrs Ruchi Singh Chauhan. "MPSO-MPPT based Single Phase Grid PV System for Power Enhancement." SMART MOVES JOURNAL IJOSCIENCE 4, no. 4 (April 20, 2018): 12. http://dx.doi.org/10.24113/ijoscience.v4i4.129.
Анотація:
The solar power became a challenging area among other renewable energy sources (RESs) since the photovoltaic (PV) systems have the benefits of not inflicting pollution, having low maintenance, and durable operation life. Besides these benefits, a PV system has many drawbacks like significantly higher installation cost comparing some other RESs, and limited potency ranges between 9–18%. The feasibility analyses have a good role so as to work out the foremost appropriate plant site before installation. On the other hand, the operating analyses and enhancements supported maximum power point tracking (MPPT) are quite necessary to extend the harvested total energy. To maximize the performance of solar photovoltaics (PV) under dynamic climatic conditions, MPPT (Maximum Power Point Tracking) controllers are integrated into photovoltaic systems. This research presents a modified PSO algorithm based on the method of tracking the maximum global power point used for photovoltaic systems with variable co-efficient. The modified PSO (MPSO) algorithm is able to trace the maximum global power point faster. This improves the effectiveness of follow-up. Simulation results show that MPSO coordination control methods have better tracking accuracy as compared to P&O as well as PSO MPPT Technique. This also improves the energy efficiency of the photovoltaic system.
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Derbeli, Mohamed, Oscar Barambones, and Lassaad Sbita. "A Robust Maximum Power Point Tracking Control Method for a PEM Fuel Cell Power System." Applied Sciences 8, no. 12 (December 1, 2018): 2449. http://dx.doi.org/10.3390/app8122449.
Анотація:
Taking into account the limited capability of proton exchange membrane fuel cells (PEMFCs) to produce energy, it is mandatory to provide solutions, in which an efficient power produced by PEMFCs can be attained. The maximum power point tracker (MPPT) plays a considerable role in the performance improvement of the PEMFCs. Conventional MPPT algorithms showed good performances due to their simplicity and easy implementation. However, oscillations around the maximum power point and inefficiency in the case of rapid change in operating conditions are their main drawbacks. To this end, a new MPPT scheme based on a current reference estimator is presented. The main goal of this work is to keep the PEMFCs functioning at an efficient power point. This goal is achieved using the backstepping technique, which drives the DC–DC boost converter inserted between the PEMFC and the load. The stability of the proposed algorithm is demonstrated by means of Lyapunov analysis. To verify the ability of the proposed method, an extensive simulation test is executed in a Matlab–Simulink T M environment. Compared with the well-known proportional–integral (PI) controller, results indicate that the proposed backstepping technique offers rapid and adequate converging to the operating power point.
10
Syzdykov, A. B. "LGORITHM FOR FINDING MAXIMUM POWER POINT TRACKING WHEN SHADOWING OR FAILURE OF SOLAR PANELPHOTO CELLS ON SATELLITES USING LOW ORBITS." Eurasian Physical Technical Journal 20, no. 1(43) (March 20, 2023): 65–72. http://dx.doi.org/10.31489/2023no1/65-72.
Анотація:
Solar cell shading or the failure of several photocells changes the output current-voltage characteristic. This paper discusses an algorithm for approaching and searching the maximum power generated on board the spacecraft, which is all-important for fast charging of the secondary sources of electrical energy since the time spent on the sunny side in low orbits are limited by time. Currently, algorithms for finding maximum power work in idealcases, and simple and effective algorithms are needed in cases of solar panel shading or failure of photocell/cells. In this paper, a simulation of a solar panel in various conditions is carried out. An algorithm for constructing the output volt ampere characteristics of a solar cell and a solar panel is implemented. Experiments of various algorithms on real devices have also been carried out.
Дисертації з теми "Limited power point tracking":
1
Liu, Hongliang. "Contribution for integrating urban wind turbine into electrical microgrid : modeling and control." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2331/document.
Анотація:
L’intégration de l’énergie éolienne, qui est une ressource renouvelable très utilisée, n’est pas toujours facile pour le micro-réseau urbain. Dans cette thèse, une éolienne urbaine basée sur une machine synchrone à aimants permanents (MSAP) est étudiée pour être intégrée dans un micro-réseau urbain à courant continu. Un état de l'art concernant les énergies renouvelables, les micro-réseaux à courant continu et les stratégies de contrôle de la production d'énergie éolienne, est réalisée. Basé sur un modèle d’éolienne urbaine répondant à la demande du système électrique, qui se compose d’un émulateur de vent et de pales, un MSAP et un convertisseur DC/DC, cette thèse propose des méthodes de poursuite du point de puissance maximale satisfaisant à l’obligation de produire de l’énergie dans la mesure du possible. Une stratégie de contrôle à puissance limitée répond correctement. De simples à complexes, quatre algorithmes MPPT, P&O à pas fixe, P&O à pas variable avec la méthode Newton-Raphson améliorée, P&O à pas variable à base de logique floue et une méthode indirecte de type lookup table, sont étudiés et implémentés pour être comparés à l’aide de trois profils de vitesse du vent. Par expérimentation, les algorithmes MPPT et PLC sont comparés, analysés et discutés. Résumant tous les résultats expérimentaux, la méthode lookup table peut gérer toutes les exigences du mode de fonctionnement MPPT en présentant la meilleure performance, mais, dans le mode de fonctionnement PLC, la P&O à base de logique floue présente les meilleures performancesThe integration of the wind power, which is one mostly used renewable resource, is always one challenger for urban microgrid. In this thesis, one urban wind turbine based on a permanent magnet synchronous machine (PMSM) is studied in order to be integrated into a DC urban microgrid. A state of the art concerning the renewable energies, DC microgrid, and control strategies of wind power generation is done. Based on a model of urban wind turbine fitting the demand of urban electric system, which consists of an emulator of wind speed and blades, a PMSM and a DC/DC converter, this thesis proposes the maximum power point tracking (MPPT) methods satisfying the requirement of producing energy as much as possible, and power limited control (PLC) strategies answering the demand of flexible energy production. From simple to complex, four MPPT algorithms including Perturbation and Observation (P&O) fixed step-size method, P&O with improved Newton-Raphson method, P&O with fuzzy logic method and lookup table method are studied and implemented to be compared with each other using three wind velocity profiles. According to the experience about MPPT subject, four PLC algorithms are introduced and implemented to be analyzed and compared with each other with one power demand profile calculated randomly. Summarizing all experimental results, the lookup table method can handle all requirement of MPPT operating mode supplying the best performance, however, in the condition of more flexible power demand operating mode, the combination of P&O and fuzzy logic method presents the best performance and potential which can be achieved in future works
2
Aourir, Mazian Jamila. "Modeling and control of an urban wind turbine intended to be integrated into an electrical microgrid." Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2669.
Анотація:
La forte consommation mondiale d'énergies fossiles accélère leur épuisement et menace l'équilibre environnemental de la Terre. Pour cela, de nouvelles catégories d'énergies basées sur des sources renouvelables sont développées pour construire un nouveau mix énergétique diversifié et décarboné. Afin de permettre une pénétration massive de ces sources d'énergie renouvelables (SER) dans le réseau public, l'utilisation de nouvelles structures de système électrique semble être une solution prometteuse, compte tenu de plusieurs aspects tels que les coûts, la sécurité d'approvisionnement, et la facilité de mise en œuvre. Ainsi, des micro-réseaux constitués de sources d'énergie décentralisées et de systèmes de stockage d'énergie ont été développés pour remplacer ou compléter le réseau centralisé principal. Ils peuvent assurer certaines fonctions de support, c'est-à-dire l'amélioration de la stabilité du réseau, le fonctionnement au démarrage à vide, le remplacement des générateurs diesel, etc. De plus, les consommateurs deviennent des producteurs et peuvent injecter une partie de leur surplus d'énergie dans le réseau public. En milieu urbain, le système solaire photovoltaïque (PV) a fait l'objet d'études approfondies depuis des décennies et est largement utilisé grâce à ses nombreux avantages tels qu'un faible impact environnemental, une intégration facile dans les bâtiments, une réduction des pertes pendant le transport, etc. Récemment, les éoliennes de faible puissance sont également de plus en plus utilisées, comme source complémentaire pour les systèmes PV, en particulier pour les applications dans les zones urbaines où la vitesse du vent est de quelques mètres par seconde. Cependant, l'utilisation de l'énergie éolienne constitue aujourd'hui un défi pour le micro-réseau urbain. Dans cette thèse, deux types d'études sont menés pour une éolienne urbaine de faible puissance. i) la première concerne de nouvelles stratégies de contrôle de puissance pour cette catégorie d’éolienne. Elle traite le suivi du point de puissance limité (LPPT) en tant que nouvelle technologie émergente des contrôleurs pour la gestion d’énergie. Le LPPT fonctionne de manière à ce que la puissance demandée par l'utilisateur puisse être extraite de l'éolienne tout en en respectant les contraintes et les limites. Cependant, le fonctionnement en mode LPPT nécessite toujours une compréhension approfondie pour obtenir un compromis entre la minimisation des oscillations de puissance et la réponse transitoire. Pour cela, trois stratégies de contrôle de puissance LPPT, pour une éolienne de faible puissance, basées sur le principe de perturbation et d'observation (P&O) sont étudiées. Les algorithmes proposés sont P&O à pas fixe, P&O à pas variable basé sur la méthode de Newton Raphson et P&O à pas variable basés sur la technique de la logique floue (FL). Les résultats expérimentaux montrent que toutes les méthodes fonctionnent correctement et atteignent le point de puissance limitée (LPP). La méthode FL montre de bonnes performances dynamiques avec des oscillations plus stables autour de LPP par rapport aux autres méthodes. ii) la deuxième étude consiste à l'intégration de cette éolienne dans un micro-réseau à courant continu. Les SER (sources PV et l’éolienne), le stockage et le réseau public constitue le micro-réseau étudié et un système de supervision est suggéré pour la gestion d’énergie. L'équilibre de puissance est assuré grâce à la gestion de puissance en temps réel dans la couche opérationnelle du système de supervision. La puissance est gérée sur la base de règles établies selon plusieurs aspects, tels que le coût ou le tarif énergétique de chaque composant et ses limitations physiques. L'excès de puissance produite par les sources renouvelables est l'un des problèmes auxquels est confrontée la fiabilité du micro-réseau et doit être résoluThe high global consumption of fossil energy fuels is accelerating their depletion and threatening the Earth's environmental balance. For that, new categories of energy based on renewable sources are developed to build a new diversified and decarbonized energy mix. In order to allow a massive penetration of these renewable energy sources (RESs) into the conventional grid, the use of new electrical system structures seems to be a promising solution, taking into account several aspects such as the costs, the security of supply, and the ease of implementation. Thus, microgrids (MGs) constituted by decentralized energy sources and energy storage systems have been developed to replace or complement the main centralized grid. They can ensure some support functions, i.e., enhancement of the grid stability, black-start operation, replacement of diesel generators, etc. In addition, the consumers become producers and are able to inject a part of their surplus of energy into the public grid. In urban areas, the solar photovoltaic (PV) system has been extensively examined for decades and is widely used thanks to its many advantages such as low environmental impact, easy integration in buildings, reduction of transportation losses, etc. Recently, small-scale wind turbines (SSWTs) are also becoming more and more used, as a complementary source for PV systems, especially for applications near ground level and in urban areas where wind speed is a few meters per second. However, the use of wind power is still nowadays a challenge for the urban MG. In this present thesis, two different types of studies are conducted for a SSWT. i) the first one concerns new power control strategies for a SSWT. It deals with limited power point tracking (LPPT) as an emerging new technology for power management controllers for SSWTs. The LPPT operates in such a way that power requested by the user can be extracted from the wind turbine (WT) while respecting constraints and limitations. However, operating in LPPT mode still requires a deep understanding to obtain a compromise between minimizing power oscillations and transient response. For that, three LPPT power control strategies for a SSWT based on the perturb and observe (P&O) principle are investigated. The proposed algorithms are P&O with fixed step size, P&O based on Newton’s method, and P&O based on the fuzzy logic (FL) technique. The experimental results highlight that all methods function correctly and reach the limited power point (LPP). The FL method shows good dynamic performances with more steady oscillations around LPP compared to other methods. ii) in the second study in this thesis, the integration of a SSWT into a direct current (DC) MG was investigated. The RESs (PV sources and WT), storage, and public grid are included and a supervisory system is suggested to manage the power. The power balance is ensured thanks to the real-time power management in the operational layer of the supervisory system. The power is managed based on the rules made according to several aspects, such as every component's energy cost or tariff and its physical limitations. Excess of power produced by PV sources and WT is one of the problems that face the reliability of the MG and should be resolved. Thus, a strategy to limit power from each source is suggested. It is based on two coefficients called “shedding coefficients” that have the role of calculating the quantity of power that should be limited from each source. Simulation tests are carried out using two power management strategies: optimization and without optimization (storage priority). The results reveal that the coefficient reduces the overall cost and whatever the coefficient that is applied, optimization still provides good performances and significantly reduces the global cost
3
Duncan, Joseph 1981. "A global maximum power point tracking DC-DC converter." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33152.
Анотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 79-80).
This thesis describes the design, and validation of a maximum power point tracking DC-DC converter capable of following the true global maximum power point in the presence of other local maximum. It does this without the use of costly components such as analog-to-digital converters and microprocessors. It substantially increases the efficiency of solar power conversion by allowing solar cells to operate at their ideal operating point regardless of changes in load, and illumination. The converter switches between a dithering algorithm which tracks the local maximum and a global search algorithm for ensuring that the converter is operating at the true global maximum.
by Joseph Duncan.
M.Eng.
4
Acharya, Parash. "Small Scale Maximum Power Point Tracking Power Converter for Developing Country Application." Thesis, University of Canterbury. Electrical and Computer Engineering, 2013. http://hdl.handle.net/10092/8608.
Анотація:
This thesis begins with providing a basic introduction of electricity requirements for small developing
country communities serviced by small scale generating units (focussing mainly on small
wind turbine, small Photo Voltaic system and Micro-Hydro Power Plants). Scenarios of these
small scale units around the world are presented. Companies manufacturing different size wind
turbines are surveyed in order to propose a design that suits the most abundantly available and
affordable turbines.
Different Maximum Power Point Tracking (MPPT) algorithms normally employed for these
small scale generating units are listed along with their working principles. Most of these algorithms
for MPPT do not require any mechanical sensors in order to sense the control parameters
like wind speed and rotor speed (for small wind turbines), temperature and irradiation (for PV
systems), and water flow and water head (for Micro-Hydro). Models for all three of these
systems were developed in order to generate Maximum Power Point (MPP) curves. Similarly,
a model for Permanent Magnet Synchronous Generators (PMSGs) has been developed in the
d-q reference frame. A boost rectifier which enables active Power Factor Correction (PFC) and
has a DC regulated output voltage is proposed before implementing a MPPT algorithm. The
proposed boost rectifier works on the principle of Direct Power Control Space Vector Modulation
(DPC-SVM) which is based on instantaneous active and reactive power control loops. In this
technique, the switching states are determined according to the errors between commanded and
estimated values of active and reactive powers.
The PMSG and Wind Turbine behaviour are simulated at various wind speeds. Similarly, simulation
of the proposed PFC boost rectifier is performed in matlab/simulink. The output of these
models are observed for the variable wind speeds which identifies PFC and boosted constant DC
output voltage is obtained. A buck converter that employs the MPPT algorithm is proposed
and modeled. The model of a complete system that consists of a variable speed small wind
turbine, PMSG, DPC-SVM boost rectifier, and buck converter implementing MPPT algorithm
is developed. The proposed MPPT algorithm is based upon the principle of adjusting the duty
ratio of the buck converter in order reach the MPP for different wind speeds (for small wind turbines) and different water flow rates (Micro-Hydro).
Finally, a prototype DPC-SVM boost rectifier and buck converter was designed and built for a
turbine with an output power ranging from 50 W-1 kW. Inductors for the boost rectifier and
buck DC-DC converter were designed and built for these output power ranges. A microcontroller
was programmed in order to generate three switching signals for the PFC boost rectifier and one
switching signal for the MPPT buck converter. Three phase voltages and currents were sensed
to determine active and reactive power. The voltage vectors were divided into 12 sectors and a
switching algorithm based on the DPC-SVM boost rectifier model was implemented in order to
minimize the errors between commanded and estimated values of active and reactive power.
The system was designed for charging 48 V battery bank. The generator three phase voltage
is boosted to a constant 80 V DC. Simulation results of the DPC-SVM based rectifier shows
that the output power could be varied by varying the DC load maintaining UPF and constant
boosted DC voltage. A buck DC-DC converter is proposed after the boost rectifier stage in
order to charge the 48 V battery bank. Duty ratio of the buck converter is varied for varying the
output power in order to reach the MPP. The controller prototype was designed and developed.
A laboratory setup connecting 4 kW induction motor (behaving as a wind turbine) with 1kW
PMSG was built. Speed-torque characteristic of the induction motor is initially determined.
The torque out of the motor varies with the motor speed at various motor supply voltages. At
a particular supply voltage, the motor torque reaches peak power at a certain turbine speed.
Hence, the control algorithm is tested to reach this power point. Although the prototype of
the entire system was built, complete results were not obtained due to various time constraints.
Results from the boost rectifier showed that the appropriate switching were performed according
to the digitized signals of the active and reactive power errors for different voltage sectors.
Simulation results showed that for various wind speed, a constant DC voltage of 80 V DC is
achieved along with UPF. MPPT control algorithm was tested for induction motor and PMSG
combination. Results showed that the MPPT could be achieved by varying the buck converter
duty ratio with UPF achieved at various wind speeds.
5
Aldobhani, Abdulaziz Mohamed Saeed. "Maximum power point tracking of PV system using ANFIS prediction and fuzzy logic tracking." Thesis, De Montfort University, 2008. http://hdl.handle.net/2086/4284.
Анотація:
Operating faraway from maximum power point decreases the generated power from photovoltaic (PV) system. For optimum operation, it is necessary to continually track the maximum power point of the PV solar array. However with huge changes in external influences and the nonlinear relationship of electrical characteristics of PV panels it is a difficult problem to identify the maximum power point as a function of these influences. Many tracking control strategies have been proposed to track maximum power point such as perturb and observe, incremental conductance, parasitic capacitance, and neural networks. These proposed methods have some disadvantages such as high cost, difficulty, complexity and nonstability. This thesis presents a novel approach based on Adaptive NeuroFuzzy Inference System (ANFIS) to predict the maximum power point utilising the actual field data, which is performed in different environmental conditions. The short circuit current and open circuit voltage are used as inputs to PV panels instead of solar irradiation and cell junction temperature. The predicted $V_{max}$from ANFIS model is used as a reference voltage for fuzzy logic controller (FLC). The FLC is used to adjust the duty cycle of the electronic switch of two types of DC-DC converter. These DC-DC converters are used to interface between the load voltage and PV panels. The duty cycle of the electronic switch of the DC-DC converter is adjusted until the input voltage of the converter tracks the predicted $V_{max}$of the PV system. FLC rules and membership functions are designed to achieve the most promising performance at different environmental conditions, different load types and different rate of changes in the duty cycle of Buck-Boost and Buck converters. The membership functions and fuzzy rules of FLC are designed to balance between different required features such as quick tracking under different environmental conditions, high accuracy, stability and high efficiency.
6
Gamboa, Gustavo. "REALIZATION OF POWER FACTOR CORRECTION AND MAXIMUM POWER POINT TRACKING FOR LOW POWER WIND TURBINES." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4283.
Анотація:
In recent years, wind energy technology has become one of the top areas of interest for energy harvesting in the power electronics world. This interest has especially peaked recently due to the increasing demand for a reliable source of renewable energy. In a recent study, the American Wind Energy Association (AWEA) ranked the U.S as the leading competitor in wind energy harvesting followed by Germany and Spain. Although the United States is the leading competitor in this area, no one has been able successfully develop an efficient, low-cost AC/DC convertor for low power turbines to be used by the average American consumer. There has been very little research in low power AC/DC converters for low to medium power wind energy turbines for battery charging applications. Due to the low power coefficient of wind turbines, power converters are required to transfer the maximum available power at the highest efficiency. Power factor correction (PFC) and maximum power point tracking (MPPT) algorithms have been proposed for high power wind turbines. These turbines are out of the price range of what a common household can afford. They also occupy a large amount of space, which is not practical for use in one's home. A low cost AC/DC converter with efficient power transfer is needed in order to promote the use of cheaper low power wind turbines. Only MPPT is implemented in most of these low power wind turbine power converters. The concept of power factor correction with MPPT has not been completely adapted just yet. The research conducted involved analyzing the effect of power factor correction and maximum power point tracking algorithm in AC/DC converters for wind turbine applications. Although maximum power to the load is always desired, most converters only take electrical efficiency into consideration. However, not only the electrical efficiency must be considered, but the mechanical energy as well. If the converter is designed to look like a purely resistive load and not a switched load, a wind turbine is able to supply the maximum power with lower conduction loss at the input side due to high current spikes. Two power converters, VIENNA with buck converter and a Buck-boost converter, were designed and experimentally analyzed. A unique approach of controlling the MPPT algorithm through a conductance G for PFC is proposed and applied in the VIENNA topology. On the other hand, the Buck-boost only operates MPPT. With the same wind profile applied for both converters, an increase in power drawn from the input increased when PFC was used even when the power level was low. Both topologies present their own unique advantages. The main advantage for the VIENNA converter is that PFC allowed more power extraction from the turbine, increasing both electrical and mechanical efficiency. The buck-boost converter, on the other hand, presents a very low component count which decreases the overall cost and volume. Therefore, a small, cost-effective converter that maximizes the power transfer from a small power wind turbine to a DC load, can motivate consumers to utilize the power available from the wind.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
7
Aashoor, Fathi. "Maximum power point tracking techniques for photovoltaic water pumping system." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683537.
Анотація:
An investigation into the design of a stand-alone photovoltaic water pumping system for supplying rural areas is presented. It includes a study of system components and their modelling. The PV water pumping system comprises a solar-cell-array, DC-DC buck chopper and permanent-magnet DC motor driving a centrifugal pump. The thesis focuses on increasing energy extraction by improving maximum power point tracking (MPPT). From different MPPT techniques previously proposed, the perturb and observe (P&O) technique is developed because of its ease of implementation and low implementation cost. A modified variable step-size P&O MPPT algorithm is investigated which uses fuzzy logic to automatically adjust step-size to better track maximum power point. Two other MPPT methods are investigated: a new artificial neural network (ANN) method and fuzzy logic (FL) based method. These use PV source output power and the speed of the DC pump motor as input variables. Both generate pulse width modulation (PWM) control signals to continually adjust the buck converter to maximize power from the PV array, and thus motor speed and the water discharge rate of a centrifugal pump. System elements are individually modelled in MATLAB/SIMULINK and then connected to assess performance under different PV irradiation levels. First, the MP&O MPPT technique is compared with the conventional P&O MPPT algorithm. The results show that the MP&O MPPT has faster dynamic response and eliminates oscillations around the MPP under steady-state conditions. The three proposed MPPT methods are implemented in the simulated PV water pumping system and compared. The results confirm that the new methods have improved energy extraction and dynamic tracking compared with simpler methods.
8
Sanders, Dustin R. "Maximum Power Point Tracking and Communications for Solar Powered Vehicles." Thesis, Southern Illinois University at Edwardsville, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10010780.
Анотація:
The SIUe solar car team lacks a competitive communication system. To enable the competitive edge a major upgrade to the electronics and wiring was required. A new maximum power point tracker and driver support system was developed to give them the competitive edge.
9
Kang, Byung O. "Maximum Power Point Tracking Using Kalman Filter for Photovoltaic System." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/30920.
Анотація:
This thesis proposes a new maximum power point tracking (MPPT) method for photovoltaic (PV) systems using Kalman filter. The Perturbation & Observation (P&O) method is widely used due to its easy implementation and simplicity. The P&O usually requires a dithering scheme to reduce noise effects, but the dithering scheme slows the tracking response time. Tracking speed is the most important factor for improving efficiency under frequent environmental change.
The proposed method is based on the Kalman filter. An adaptive MPPT algorithm which uses an instantaneous power slope has introduced, but process and sensor noises disturb its estimations. Thus, applying the Kalman filter to the adaptive algorithm is able to reduce tracking failures by the noises. It also keeps fast tracking performance of the adaptive algorithm, so that enables using the Kalman filter to generate more powers under rapid weather changes than using the P&O.
For simulations, a PV system is introduced with a 30kW array and MPPT controller designs using the Kalman filter and P&O. Simulation results are provided the comparison of the proposed method and the P&O on transient response for sudden system restart and irradiation changes in different noise levels. The simulations are also performed using real irradiance data for two entire days, one day is smooth irradiance changes and the other day is severe irradiance changes. The proposed method has showed the better performance when the irradiance is severely fluctuating than the P&O while the two methods have showed the similar performances on the smooth irradiance changes.Master of Science
10
Gohar, Ali Hina. "Maximum Power Point Tracking of Photovoltaic system using Non-Linear Controllers." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/671122.
Анотація:
La creixent demanda energètica, l’esgotament dels combustibles fòssils i l’augment de l’escalfament global a causa de l’emissió de carboni ha donat lloc a la necessitat d’un sistema energètic alternatiu, global i respectuós amb el medi ambient. L’energia solar es considera una de les formes d’energia més inesgotables d’aquest univers, però té el problema de la baixa eficiència a causa de les diferents condicions ambientals. El panell solar presenta un comportament no lineal en condicions climàtiques reals i la potència de sortida fluctua amb la variació de la irradiació solar i la temperatura. El canvi de les condicions meteorològiques i el comportament no lineal dels sistemes fotovoltaics suposen un repte en el seguiment de diferents PowerPoint màxims. Per tant, per extreure i lliurar contínuament la màxima potència possible del sistema fotovoltaic, en determinades condicions ambientals, s’ha de formular l’estratègia de control de seguiment del punt de potència màxima (MPPT) que funcioni contínuament el sistema fotovoltaic al seu MPP. Es necessita un controlador no lineal robust per garantir el MPPT mitjançant la manipulació de les línies no lineals d’un sistema i el fa robust contra les condicions ambientals canviants. El control de mode lliscant (SMC) s’utilitza àmpliament en sistemes de control no lineals i s’ha implementat en sistemes fotovoltaics (PVC) per rastrejar MPP.
SMC és robust contra les pertorbacions, les incerteses del model i les variacions paramètriques. Representa fenòmens indesitjables com el xerramec, inherent al fet que provoca pèrdues d’energia i calor.
En aquesta tesi, en primer lloc, es formula un controlador SMC d’ordre sencer per extreure la màxima potència d’un sistema solar fotovoltaic en condicions climàtiques variables que utilitzen l’esquema MPPT de pertorbació i observació (P \ & O) del sistema fotovoltaic autònom proposat. El sistema proposat consta de dos esquemes de bucles, a saber, el bucle de cerca i el bucle de seguiment. P&O MPPT s’utilitza al bucle de cerca per generar el senyal de referència i un controlador SMC de seguiment s’utilitza a l’altre bucle per extreure la màxima potència fotovoltaica. El sistema fotovoltaic es connecta amb la càrrega mitjançant el convertidor d’alimentació electrònic DC-DC de potència. Primer es deriva un model matemàtic del convertidor d’augment i, basat en el model derivat, es formula un SMC per controlar els impulsos de la porta del commutador del convertidor d’augment. L’estabilitat del sistema de bucle tancat es verifica mitjançant el teorema d’estabilitat de Lyapunov. L’esquema de control proposat es prova amb diferents nivells d’irradiació i els resultats de la simulació es comparen amb el controlador de derivades integrals proporcionals clàssiques (PID).
El SMC clàssic representa fenòmens indesitjables com el xerramec, inherent al fet que provoca pèrdues d’energia i calor. A la següent part d’aquesta tesi, es discuteix el disseny del controlador de mode lliscant adaptatiu (ASMC) per al sistema fotovoltaic proposat. El control adoptat s’executa mitjançant un ASMC i la millora s’actualitza mitjançant un algorisme d’optimització MPPT de mètode de cerca de patrons millorats (IPSM). S’utilitza un MPPT IPSM per generar la tensió de referència per tal de comandar el controlador ASMC subjacent. S’ha dut a terme una comparació amb altres dos algoritmes d’optimització, a saber, Perturb \ & Observe (P&O) i Particle Swarm Optimization (PSO) amb IPSM per MPPT. Com a estratègia no lineal, l’estabilitat del controlador adaptatiu es garanteix mitjançant la realització d’una anàlisi de Lyapunov. El rendiment de les arquitectures de control proposades es valida comparant les propostes amb la del conegut i àmpliament utilitzat controlador PID.La creciente demanda de energía, el agotamiento de los combustibles fósiles y el aumento del calentamiento global debido a la emisión de carbono han hecho surgir la necesidad de un sistema energético alternativo, de eficiencia general y respetuoso con el medio ambiente. La energía solar se considera una de las formas de energía más inagotables de este universo, pero tiene el problema de la baja eficiencia debido a las diferentes condiciones ambientales. El panel solar exhibe un comportamiento no lineal en condiciones climáticas reales y la potencia de salida fluctúa con la variación de la irradiancia solar y la temperatura. Las condiciones climáticas cambiantes y el comportamiento no lineal de los sistemas fotovoltaicos plantean un desafío en el seguimiento de la variación máxima de PowerPoint. Por lo tanto, para extraer y entregar continuamente la máxima potencia posible del sistema fotovoltaico, en determinadas condiciones ambientales, se debe formular la estrategia de control de seguimiento del punto de máxima potencia (MPPT) que opere continuamente el sistema fotovoltaico en su MPP. Se requiere un controlador no lineal robusto para asegurar MPPT manejando las no linealidades de un sistema y haciéndolo robusto frente a condiciones ambientales cambiantes. El control de modo deslizante (SMC) se usa ampliamente en sistemas de control no lineales y se ha implementado en sistemas fotovoltaicos (PVC) para rastrear MPP. SMC es robusto contra perturbaciones, incertidumbres del modelo y variaciones paramétricas. Representa fenómenos indeseables como el parloteo, inherentes a él, que provocan pérdidas de energía y calor. En esta tesis, en primer lugar, se formula un controlador SMC de orden entero para extraer la máxima potencia de un sistema fotovoltaico solar en condiciones climáticas variables empleando el esquema MPPT de perturbar y observar (P&O) para el sistema fotovoltaico autónomo propuesto. El sistema propuesto consta de dos esquemas de bucles, a saber, el bucle de búsqueda y el bucle de seguimiento. P&O MPPT se utiliza en el bucle de búsqueda para generar la señal de referencia y se utiliza un controlador SMC de seguimiento en el otro bucle para extraer la máxima potencia fotovoltaica. El sistema fotovoltaico está conectado con la carga a través del convertidor elevador DC-DC electrónico de potencia. Primero se deriva un modelo matemático del convertidor elevador y, en base al modelo derivado, se formula un SMC para controlar los pulsos de puerta del interruptor del convertidor elevador. La estabilidad del sistema de circuito cerrado se verifica mediante el teorema de estabilidad de Lyapunov. El esquema de control propuesto se prueba bajo diferentes niveles de irradiancia y los resultados de la simulación se comparan con el controlador clásico proporcional integral derivado (PID). El SMC clásico describe fenómenos indeseables como el parloteo, inherente a él, que causa pérdidas de energía y calor. En la siguiente parte de esta tesis, se analiza el diseño del controlador de modo deslizante adaptativo (ASMC) para el sistema fotovoltaico propuesto. El control adoptado se ejecuta utilizando un ASMC y la mejora se actualiza utilizando un algoritmo de optimización MPPT del Método de búsqueda de patrón mejorado (IPSM). Se utiliza un IPSM MPPT para generar el voltaje de referencia para controlar el controlador ASMC subyacente. Se ha realizado una comparación con otros dos algoritmos de optimización, a saber, Perturb \ Observe (P&O) y Particle Swarm Optimization (PSO) con IPSM para MPPT. Como estrategia no lineal, la estabilidad del controlador adaptativo está garantizada mediante la realización de un análisis de Lyapunov.
The increasing energy demands, depleting fossil fuels, and increasing global warming due to carbon emission has arisen the need for an alternate, overall efficiency, and environment-friendly energy system. Solar energy is considered to be one of the most inexhaustible forms of energy in this universe, but it has the problem of low efficiency due to varying environmental conditions. Solar panel exhibits nonlinear behavior under real climatic conditions and output power fluctuates with the variation in solar irradiance and temperature. Changing weather conditions and nonlinear behavior of PV systems pose a challenge in the tracking of varying maximum PowerPoint. Hence, to continuously extract and deliver the maximum possible power from the PV system, under given environmental conditions, the maximum power point tracking (MPPT) control strategy needs to be formulated that continuously operates the PV system at its MPP. A robust nonlinear controller is required to ensure MPPT by handling nonlinearities of a system and making it robust against changing environmental conditions. Sliding mode control (SMC) is extensively used in non-linear control systems and has been implemented in photovoltaic systems (PV) to track MPP. SMC is robust against disturbances, model uncertainties, and parametric variations. It depicts undesirable phenomena like chattering, inherent in it causing power and heat losses. In this thesis, first, an integer order SMC controller is formulated for extracting maximum power from a solar PV system under variable climatic conditions employing the perturb and observe (P&O) MPPT scheme for the proposed stand-alone PV system. The proposed system consists of two loops schemes, namely the searching loop and the tracking loop. P&O MPPT is utilized in the searching loop to generate the reference signal and a tracking SMC controller is utilized in the other loop to extract the maximum PV power. PV system is connected with load through the power electronic DC-DC boost converter. A mathematical model of the boost converter is derived first, and based on the derived model, an SMC is formulated to control the gate pulses of the boost converter switch. The closed-loop system stability is verified through the Lyapunov stability theorem. The proposed control scheme is tested under varying irradiance levels and the simulation results are compared with the classical proportional integral derivative (PID) controller. Classical SMC depicts undesirable phenomena like chattering, inherent in it causing power and heat losses. In the next part of this thesis, the design of the adaptive sliding mode controller (ASMC) is discussed for the proposed PV system. The adopted control is executed utilizing an ASMC and the enhancement is actualized utilizing an Improved Pattern Search Method (IPSM) MPPT optimization algorithm. An IPSM MPPT is used to generate the reference voltage in order to command the underlying ASMC controller. Comparison with two other optimization algorithms, namely, a Perturb & Observe (P&O) and Particle Swarm Optimization (PSO) with IPSM for MPPT has been conducted. As a non-linear strategy, the stability of the adaptive controller is guaranteed by conducting a Lyapunov analysis. The performance of the proposed control architectures is validated by comparing the proposals with that of the well-known and widely used PID controller. The simulation results validate that the proposed controller effectively improves the voltage tracking, system power with reduced chattering effect, and steady-state error. A tabular comparison is provided at the end of each optimization algorithm category as a resume quantitative comparison. It is anticipated that this work will serve as a reference and provides important insight into MPPT control of the PV systems.
Книги з теми "Limited power point tracking":
1
Eltamaly, Ali M., and Almoataz Y. Abdelaziz, eds. Modern Maximum Power Point Tracking Techniques for Photovoltaic Energy Systems. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-05578-3.
2
Great Britain. Her Majesty's Inspectorate of Pollution. Radioactive Substances Act 1993: Decisions by the Chief Inspector and the Minister on applications by the AGR & PWR Company Limited to dispose of radioactive wastes from the Dungeness B, Hartlepool, Heysham 1, Heysham 2, Hinkley Point B and Sizewell B nuclear power stations. [London]: Her Majesty's Inspectorate of Pollution and Ministry of Agriculture, Fisheries and Food, 1996.
3
Furst, Eric M., and Todd M. Squires. Interferometric tracking. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199655205.003.0006.
Анотація:
The purpose of this chapter is to present a survey of passive microrheology techniques that are important complements to more widely used particle tracking and light scattering methods. Such methods include back focal plane interferometry and extensions of particle tracking to measure the rotation of colloidal particles. Methods of passive microrheology using back focal plane interferometry are presented, including the experimental design and detector sensitivity and limits in frequency bandwidth and spatial resolution. The Generalized Stokes Einstein relation is derived from linear response theory of the particle position power spectrum and complex susceptibility. Applications of interoferometric tracking include high frequency microrheology and two-point measurements. Lastly, the chapter includes a discussion of rotational passive microrheology and the rotational GSER.
4
Hébert, Maurice. Maximum Power Point Tracking: Background, Implementation and Classification. Nova Science Publishers, Incorporated, 2020.
5
Eltamaly, Ali M., and Almoataz Y. Abdelaziz. Modern Maximum Power Point Tracking Techniques for Photovoltaic Energy Systems. Springer, 2019.
6
Sharma, Kamalkant, Sahil Attri, and Inderpreet Kaur. Maximum Power Point Tracking for Partially Shaded Photovoltaic Arrays Using ANN. Independently Published, 2019.
7
Generation of Sinusoidal Voltage for Grid Connected Systems Using Maximum Power Point Tracking Technique. Karur, India: ASDF International, 2017.
8
Fukuyama, Francis, and Francesca Recanatini. Beyond Measurement. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198817062.003.0003.
Анотація:
Since the 1990s, governance and anti-corruption have become preoccupations of the international development and research communities, leading to the proliferation of sophisticated measures, which, while a critical starting point, have not had significant impact at the country level. This chapter examines approaches to reducing corruption, including structural state reform, simplification and reduction of administrative discretion, transparency and accountability, international agreements and conventions, and anti-corruption bodies. While some approaches have produced results in specific areas, their impact has been limited. The chapter argues that we should think about corruption differently, not as a market distortion or unethical behaviour but as a misallocation of power. To address corruption requires interventions that reallocate power among stakeholders. The limited success in addressing corruption suggests that policy-makers and the international community have not been able to reallocate power, mostly due to lack of political leverage to discipline entrenched local actors.
9
Tourneau, Thierry Le, Luis Caballero, and Tsai Wei-Chuan. Right atrium. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0024.
Анотація:
The right atrium (RA) is located on the upper right-hand side of the heart and has relatively thin walls. From an anatomical point of view, the RA comprises three basic parts, the appendage, the vestibule of the tricuspid valve, and the venous component (superior and inferior vena cava, and the coronary sinus) receiving the deoxygenated blood. The RA is a dynamic structure dedicated to receive blood and to assist right ventricular (RV) filling. The three components of atrial function are the reservoir function during ventricular systole, the conduit function which consists in passive blood transfer from veins to the RV in diastole, and the booster pump function in relation to atrial contraction in late diastole to complete ventricular filling. Right atrial function depends on cardiac rhythm (sinus or atrial fibrillation), pericardial integrity, RV load and function, and tricuspid function. Right atrial dimension assessment is limited in two-dimensional (2D) echocardiography. Right atrial planimetry in the apical four-chamber view is commonly used with an upper normal value of 18-20 cm2. Minor and major diameters can also be measured. Three-dimensional (3D) echocardiography could overcome the limitation of conventional echocardiography in assessing RA size. Right atrial function has been poorly explored by echocardiography both in physiological and pathological contexts. Although tricuspid inflow and tissue Doppler imaging of tricuspid annulus can be used in the exploration of RA function, 2D speckle tracking and 3D echocardiography appear promising tools to dissect RA function and to overcome the limitations of standard echocardiography.
10
Jennings, Jeremy. Early Nineteenth-Century Liberalism. Edited by George Klosko. Oxford University Press, 2011. http://dx.doi.org/10.1093/oxfordhb/9780199238804.003.0020.
Анотація:
The broad outline of liberal doctrine across Europe in the first half of the nineteenth century can be easily delineated: liberals shared a fundamental commitment to individual liberty; to religious toleration; to limited government and the rule of law. Drawing on the discussion of forms of arbitrary power as a thread, this article highlights certain key themes in liberal thought up to the mid-nineteenth century. It focuses on liberalism in France and concludes with a discussion of liberalism in Britain, specifically with an analysis of the writings of John Stuart Mill. By way of background, the article first examines the account of despotism as rule by fear provided by Montesquieu in the mid-eighteenth century. It then shows how Alexis de Tocqueville was able to formulate a new concept of the oppression most likely to occur in modern societies. It does this by suggesting that we might take the concept of usurpation, formulated by Benjamin Constant, as a point of transition.
Частини книг з теми "Limited power point tracking":
1
Abdel-Salam, Mazen, Mohamed-Tharwat EL-Mohandes, and Mohamed Goda. "History of Maximum Power Point Tracking." In Modern Maximum Power Point Tracking Techniques for Photovoltaic Energy Systems, 1–29. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05578-3_1.
2
Yadav, Dilip, and Nidhi Singh. "Intelligent Techniques for Maximum Power Point Tracking." In Artificial Intelligence for Solar Photovoltaic Systems, 105–27. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003222286-5.
3
Yadav, Shilpi, Kamlesh K. Bharti, Vijay Kumar Tewari, Santosh Kumar Tripathi, and Rajesh Kumar. "Conventional Techniques for Maximum Power Point Tracking." In Artificial Intelligence for Solar Photovoltaic Systems, 79–103. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003222286-4.
4
Lyden, Sarah, M. Enamul Haque, and M. Apel Mahmud. "Maximum Power Point Tracking Methods for PV Systems." In Advances in Solar Photovoltaic Power Plants, 79–105. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-50521-2_4.
5
Guan, Ti, Lin Lin, Dawei Wang, Xin Liu, Wenting Wang, Jianpo Li, and Pengwei Dong. "Global Maximum Power Point Tracking Algorithm for Solar Power System." In Advances in Intelligent Information Hiding and Multimedia Signal Processing, 249–58. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9710-3_26.
6
Škamo, Aida, Mirza Šarić, and Lejla Vuić. "Comparison of Different Maximum Power Point Tracking Algorithms." In Lecture Notes in Networks and Systems, 117–32. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-90055-7_10.
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Mojallizadeh, M. R., and M. A. Badamchizadeh. "Application of Sliding-Mode Control for Maximum Power Point Tracking of PV Systems." In Power Systems, 25–43. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-6151-7_2.
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Xu, Wei, Chaoxu Mu, and Lei Tang. "Advanced Control Techniques for PV Maximum Power Point Tracking." In Advances in Solar Photovoltaic Power Plants, 43–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-50521-2_3.
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Wang, Meng-Hui, Wei-Jhe Jiang, and Mei-Ling Huang. "An Intelligence Maximum Power Point Tracking Controller for Human Power System." In Intelligent Information and Database Systems, 573–82. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15702-3_55.
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Fan, Rong, XiuXia Zhang, and ShunXian Bai. "A Maximum Power Point Tracking Method for Photovoltaic Systems." In Proceedings of the Second International Conference on Mechatronics and Automatic Control, 221–28. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13707-0_25.
Тези доповідей конференцій з теми "Limited power point tracking":
1
Venturini, R. P., V. V. R. Scarpa, G. Spiazzi, and S. Buso. "Analysis of limit cycle oscillations in maximum power point tracking algorithms." In 2008 IEEE Power Electronics Specialists Conference - PESC 2008. IEEE, 2008. http://dx.doi.org/10.1109/pesc.2008.4591959.
2
Jeon, Woongsun, and Rajesh Rajamani. "Active Sensing on a Bicycle for Accurate Tracking of Rear Vehicle Maneuvers." In ASME 2016 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/dscc2016-9772.
Анотація:
This paper focuses on development of an active sensing system for a bicycle to accurately track rear vehicles. Cost, size and power constraints highly limit the type of sensor that can be used on a bicycle for measurement of distances to vehicles. A single beam laser sensor mounted on a rotationally controlled platform is proposed for this sensing mission. The rotational orientation of the laser sensor needs to be controlled in real-time in order to focus on a target point on the vehicle, as the vehicle’s lateral and longitudinal distances change. This tracking problem involves two challenges: Controlling the real-time angular position of the laser sensor based on very limited information and tracking the vehicle’s position for different types of maneuvers. The first challenge is addressed by developing an algorithm to detect whether a reflection is from the front or side of the target vehicle and then controlling sensor orientation to alternately obtain both lateral and longitudinal distance measurements. The second challenge is addressed by using an interacting multiple model observer that incorporates straight and turning vehicle motion models. Simulation results are presented to show the advantages of the developed tracking control system compared to simpler alternatives.
3
Jani, Kavan, Hong Zhou, and Chung Leung. "Linkage Synthesis for Solar Tracking." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86471.
Анотація:
Solar trackers orient solar panels toward the Sun to increase solar energy harvesting. To enhance solar energy capture, solar trackers change solar panels’ orientation throughout the day to follow the Sun’s path and make solar panels normal to the solar ray. The current solar trackers make solar panels perpendicular to the solar ray because of the active motion control of the solar panels. However, they also consume considerable power since the motion of solar panels is usually generated by two motors simultaneously and continuously. The merits of the existing sensor-based dual-axis solar trackers are compromised by their motor power consumption. In this research, the Sun’s location relative to an arbitrary point on Earth is determined at any time on any day in any year. Because of the determined solar location and path, only one axis is needed for the proposed solar tracker since it does not rely on any sensor to determine the Sun’s location. The current single-axis solar trackers face challenges on the limited oscillation range of the solar panels and the potential interference between an oscillating solar panel and its corresponding ground. In this paper, a sensor-free single-axis solar tracking linkage is designed to surmount these challenges. The solar tracking motion of the designed linkage is simulated. The designed linkage is fabricated and tested. The motion of the fabricated linkage is controlled by a microcontroller to generate the desired intermittent solar tracking motion.
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Esfandiari, Masoumeh, and Nariman Sepehri. "Design and Stability Analysis of a QFT Pressure Controller of a Hydraulic Actuator Using Takagi-Sugeno Fuzzy Model." In ASME/BATH 2015 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/fpmc2015-9636.
Анотація:
In this paper, a robust, fixed-gain, and linear controller is designed for the output pressure of an electro-hydraulic actuator with parametric uncertainties. Quantitative feedback theory (QFT) is selected as the design technique. The objective is to satisfy specified performance criteria in terms of tracking, stability, and disturbance rejection. To design the QFT controller, the required family of frequency responses is obtained by linearizing the hydraulic nonlinear function around operating points of interest, and constructing an equivalent linear plant set. As a result, the stability of the closed-loop system is guaranteed only around the limited number of operating points, and specified values for system parameters. To overcome this limitation, Takagi-Sugeno (T-S) fuzzy modeling is employed. This way the nonlinear stability of the closed-loop system is investigated and ensured for a continuous range of parametric uncertainties and region of operating points. Having successful results from stability analysis, the QFT controller is applied on the experimental set-up. The experimental results are in accordance with the specified criteria.
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Davis, Edward P., R. Cengiz Ertekin, and H. Ronald Riggs. "A Buoy-Based WEC Device to Provide Low Power to Sensors." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-80091.
Анотація:
Remote ocean instrumentation and monitoring techniques often rely on floating buoys with a variety of sensors to acquire time series measurements such as ambient noise, acoustic tracking or communications. The operating lifetime of small remote buoys is limited by onboard battery power. Remote acoustic sensors with hydrophone arrays, onboard RF transmitters, GPS receivers and other support electronics can draw up to 100–200W of continuous power in operation, limiting battery life in many cases to 12 to 24 hours between recharge. Recharging is inconvenient, and often impractical to the point that many compact sonobuoys are designed to scuttle themselves after about a day. The associated cost, as well as the environmental impact of sending large amounts of battery and electronic hardware to the bottom of the ocean, is a strong driver for developing renewable ocean power sources for semi-permanent unattended buoy deployments. In support of this vision, a simple, low-cost buoy size platform capable of generating power by scavenging energy from ocean wave motion is developed and demonstrated. The phase 1 prototype is designed to deliver a minimum of 50W of average power from the wave motion characteristics. The motions and the resulting tension in the mooring line are calculated through a linear potential-based computer program. The heaving-body WEC (Wave Energy Converter) design and the modeling are discussed. The design data and the calculations are presented as part of proof of concept of the power generation mechanism and the buoy.
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MacAlpine, Sara M., Michael J. Brandemuehl, Leonor L. Linares, and Robert W. Erickson. "Effect of Distributed Power Conversion on the Annual Performance of Building-Integrated PV Arrays With Complex Roof Geometries." In ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90377.
Анотація:
Building-integrated photovoltaic (BIPV) systems have gained greater popularity in recent years; however, their effectiveness is often limited by nonuniform operating conditions. To increase potential for energy capture in PV systems, particularly those with series string configurations, an improved module integrated dc-dc converter (MIC) with maximum power point tracking has been proposed. This paper investigates the potential power gain provided by these MICs in situations where the architecture or surroundings of a building necessitate that a PV array include panels with differing orientations, which can significantly reduce system efficiency. A flexible, comprehensive simulation model for BIPV systems is developed, which allows for variations in insolation and temperature at the PV cell level, while accurately modeling MICs and their effect on array performance. This model is used to simulate various directional array combinations in series string and parallel configurations for a representative set of climates around the US. Results of these simulations show power gains attributed to both the photovoltaic generator/converter portion of the system and to increased inverter efficiency arising from a constant, controlled string voltage. When differing panel orientations within an array are considered, there is potential for annual power output gains of over 10% for a system with MICs when compared to conventional approaches. Further opportunities for increased energy capture in a BIPV system with MICs are identified and discussed.
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MacAlpine, Sara M., Michael J. Brandemuehl, and Robert W. Erickson. "Analysis of Potential for Mitigation of Building-Integrated PV Array Shading Losses Through Use of Distributed Power Converters." In ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90261.
Анотація:
Partial shading of building-integrated photovoltaic (BIPV) arrays is very common, as they are limited by building geometry and most often installed in crowded urban or suburban environments. Power losses in shaded BIPV systems tend to be disproportionately large, due in large part to mismatches in operating conditions between panels. Maximum power point tracking at a modular level, which can be achieved through the use of module integrated dc-dc converters (MICs), may be used to mitigate some of these losses. This paper investigates the potential power gain provided by MICs for several representative partially shaded BIPV array scenarios. A flexible, comprehensive simulation model for BIPV systems is developed, which allows for variations in insolation and temperature at the PV cell level, while accurately modeling MICs and their effect on array performance. Shadows from nearby objects are mapped onto the modeled BIPV arrays and simulated on an annual, hourly basis, with varying array configuration as well as object size and placement. Results of these simulations show that the impact of MICs on system power output varies depending on factors such as radiation availability, time shaded throughout the year, shadow size and distribution on the array, and inverter design. Annual power gains of 3–30% are realized for a moderately shaded system with MICs when compared to conventional approaches. Further opportunities for increased energy capture in a BIPV system with MICs are identified and discussed.
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Restrepo, Bernardo, Larry E. Banta, and David Tucker. "Simulation of Model Predictive Control for a Fuel Cell/Gas Turbine Power System Based on Experimental Data and the Recursive Identification Method." In ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2016 Power Conference and the ASME 2016 10th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fuelcell2016-59378.
Анотація:
A Model Predictive Control (MPC) strategy has been suggested and simulated with the empirical dynamic data collected on the Hybrid Performance (HyPer) project facility installed at the National Energy Technology Laboratory (NETL), U.S. Department of Energy, in Morgantown, WV. The HyPer facility is able to simulate gasifier/fuel cell power systems and uses hardware-based simulation approach that couples a modified recuperated gas turbine cycle with hardware driven by a solid oxide fuel cell model. Dynamic data was collected by operating the HyPer facility continuously during five days. Bypass valves along with electric load of the system were manipulated and variables such as mass flow, turbine speed, temperature, pressure, among others were recorded for analysis. This work was developed by focusing on a multivariable recursive system identification structure fitting measured transient data. The results showed that real-time or online data is a viable means to provide a dynamic model for controller design. The excursion dynamic data collected between the setup changes of the experiments was processed off-line to determine the feasibility of applying an adaptive Model Predictive Control strategy. One of the strengths of MPC is that it can allow the designer to impose strict limits on inputs and outputs in order to keep the system within known safe bounds. Two identification structures, ARX and a State-Space model, were used to fit the measured data to dynamic models of the HyPer facility. The State-Space identification was very accurate with a second order model. Visual inspection of the tracking accuracy shows that the ARX approach was approximately as accurate as the State-Space structure in its ability to reproduce measured data. However, by comparing the Loss Function and the FPE parameters, the State-Space approach gives better results. The MPC proved to be a good strategy to control the HyPer facility. The airflow valves and the electric load were used to control the turbine speed and the cathode airflow. For the ARX/State Space models, the MPC was very robust in tracking set-point variations. The anticipation feature of the MPC was revealed to be a good tool to compensate time delays in the output variables of the facility or to anticipate eventual set-point moves in order to achieve the objectives very quickly. The MPC also displayed good disturbance rejection on the output variables when the fuel flow was set to simulate FC heat effluent disturbances. Different off-design scenarios of operation have been tested to confirm the estimated implementation behavior of the plant-controller dynamics.
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Xiaodong Zhang, Wenlong Li, and Jiangui Li. "Thermoelectric power generation with maximum power point tracking." In 8th International Conference on Advances in Power System Control, Operation and Management (APSCOM 2009). IET, 2009. http://dx.doi.org/10.1049/cp.2009.1787.
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Moreno-Torres, Pablo, Jorge Torres, Marcos Lafoz, Miguel Yeguas, and Jaime R. Arribas. "Minimum losses point tracking and minimum current point tracking in interior PMSMs." In 2016 18th European Conference on Power Electronics and Applications (EPE'16 ECCE Europe). IEEE, 2016. http://dx.doi.org/10.1109/epe.2016.7695526.