To see the other types of publications on this topic, follow the link: Electronic load control.
Dissertations / Theses on the topic 'Electronic load control'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 33 dissertations / theses for your research on the topic 'Electronic load control.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Jadric, Ivan. "Modeling and Control of a Synchronous Generator With Electronic Load." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36549.
Full textAbstract:
Design and analysis of a system consisting of a variable-speed synchronous generator that supplies an active dc load (inverter) through a three-phase diode rectifier requires adequate modeling in both time and frequency domain. In particular, the system's control-loops, responsible for stability and proper impedance matching between generator and load, are difficult to design without an accurate small-signal model. A particularity of the described system is strong non-ideal operation of the diode rectifier, a consequence of the large value of generator's synchronous impedance. This non-ideal behavior influences both steady state and transient performance. This thesis presents a new, average model of the system. The average model accounts, in a detailed manner, for dynamics of generator and load, and for effects of the non-ideal operation of diode rectifier. The model is non-linear, but time continuous, and can be used for large- and small-signal analysis.
The developed model was verified on a 150 kW generator set with inverter output, whose dc-link voltage control-loop design was successfully carried out based on the average model.Master of Science
2
Han, Yunong. "Load-aware traffic control in software-defined enterprise Wireless Local Area Networks." Thesis, University of Essex, 2018. http://repository.essex.ac.uk/22379/.
Full textAbstract:
With the growing popularity of Bring Your Own Device (BYOD), modern enterprise Wireless Local Area Networks (WLANs) deployments always consist of multiple Access Points (APs) to meet the fast-increasing demand for wireless access. In order to avoid network congestion which leads to issues such as suboptimal Quality of Service (QoS) and degraded user Quality of Experience (QoE), intelligent network traffic control is needed. Software Defined Networking (SDN) is an emerging architecture and intensively discussed as one of the most promising technologies to simplify network management and service development. In the SDN architecture, network management is directly programmable because it is decoupled from forwarding layer. Leveraging SDN to the existing enterprise WLANs framework, network services can be flexibly implemented to support intelligent network traffic control. This thesis studies the architecture of software-defined enterprise WLANs and how to improve network traffic control from a client-side and an AP-side perspective. By extending an existing software-defined enterprise WLANs framework, two adaptive algorithms are proposed to provide client-based mobility management and load balancing. Custom protocol messages and AP load metric are introduced to enable the proposed adaptive algorithms. Moreover, a software-defined enterprise WLAN system is designed and implemented on a testbed. A load-aware automatic channel switching algorithm and a QoS-aware bandwidth control algorithm are proposed to achieve AP-based network traffic control. Experimental results from the testbed show that the designed system and algorithms significantly improve the performance of traffic control in enterprise WLANs in terms of network throughput, packet loss rate, transmission delay and jitter.
3
Boesak, C. D. "Controller design via H[infinity] optimal control, quantitative feedback theory and fuzzy logic control : an application to load frequency control." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/5249.
Full textAbstract:
Bibliography: leaves 104-112.This thesis describes the application of robust controller design techniques namely H[infinity] optimal control, fuzzy logic control and quantitative feedback theory to the load frequency control problem of power systems. It thus forms a comparative study of these design methods. Load frequency control is the closed loop control of electrical generating units to regulate the system frequency at its nominal value in the presence of load disturbances. Load frequency control also includes the regulation of the tie-line interchange powers.
4
Akpolat, Zuhtu Hakan. "Application of fuzzy-sliding mode control and electronic load emulation to the robust control of motor drives." Thesis, University of Nottingham, 1999. http://eprints.nottingham.ac.uk/28390/.
Full textAbstract:
This thesis is concerned with the experimental investigation of robust speed control strategies for the industrial motor drive systems. The first objective of the thesis is to implement a high performance programmable dynamometer which can provide desired linear and non-linear mechanical loads for the experimental validation of the robust control methods. The discrete time implementation of the conventional dynamometer control strategy (the inverse model approach) is analysed and it is shown that this method suffers from the stability and noise problems. A new dynamometer control strategy, based on speed tracking and torque feedforward compensation, is developed and successfully implemented in the experimental system. The emulation is placed in a closed loop speed control system and the experimental results are compared with the corresponding ideal simulated results for the validation of the dynamometer control strategy. The comparisons show excellent agreement for a variety of linear and nonlinear mechanical load models and such a high performance experimental load emulation results are reported for the first time in research literature. The second objective of the project is to investigate the Fuzzy Logic Control (FLC) and the Sliding Mode Control (SMC) approaches in order to develop a simple,• algorithmic and practical robust control design procedure for industrial speed drive control systems. The Reaching Law Control (RLC) method, which is an approach to SMC design, and the FLC are used together in order to develop a practical robust speed control strategy. The robustness of the proposed control approach is tested for a variety of linear and non-linear mechanical loads provided by the dynamometer. Using the new robust control method, good output responses are obtained for large parameter variations and external disturbances.
5
Skvorchevsky, A. Y. "ELS capacity control system for axial-piston pumps." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/46920.
Full text
6
Pandolfo, Massimiliano. "Modeling and control of a suspended load lifted by two aerial vehicles." Thesis, KTH, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206174.
Full textAbstract:
In this thesis we discuss the problem of lifting and stabilizing a bar-shaped slungload, held by two UAVs (Unmanned Aerial Vehicles) which are connected to it throughcables. A mathematical model of the system is presented. After describing the systemdynamics, we identify a set of equilibrium poses and discuss the stability of a point inthis set. Then, the Gazebo simulator is used to develop and test a controller capableof stabilizing the system, rejecting disturbances, and following basic trajectories.I denna avhandling diskuterar vi problemet med att lyfta och stabilisera en stavformadhängande last, hållen av två UAV:er (obemannade luftfarkoster) vilka är anslutnatill den genom kablar. En matematisk modell av systemet presenteras. Efter attbeskriva systemdynamiken identifierar vi en uppsättning jämviktslägen och diskuterarstabiliteten i en punkt i denna uppsättning. Sedan används Gazebo-simulatorn föratt utveckla och testa en regulator med förmåga att stabilisera systemet, hanterastörningar, och följa grundläggande flygbanor.
7
Joy, Dawn, and Karthik Sekaran. "Electronic Pump Control and Benchmarking of Simulation Tools : AMESim and GT Suite." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69567.
Full textAbstract:
Load sensing pumps in hydraulic system of wheel loaders helps in increasing the energy efficiency of wheel loaders. Present day machines have hydro mechanical load sensing system. After the advent of hydro mechanical load sensing concept, over the years, lots of research has been carried out relevant to electro hydraulic load sensing, trying to control the pump electronically. Currently, Volvo Construction Equipments (VCE) is interested in investigating the possibility of implementing electro hydraulic load sensing system in the wheel loaders. Research works has shown existence of several configurations of electro hydraulic load sensing pumps. Successful simulation results of an electro hydraulic load sensing pump configuration would provide a backing for the proposal of building and testing that configuration of electro hydraulic load sensing pump prototype. Also, the thesis work aims in benchmarking hydraulic system simulation capabilities of AMESim and GT- Suite by simulating the existing hydro mechanical load sensing system in both in both the simulation packages.The thesis work has been carried out at Virtual Product Development (VPD) division of Volvo Construction Equipments (VCE), Eskilstuna, Sweden.
8
Adolfsson, Mattias. "Developing a Graphical Application to Control Stepper Motors with Sensorless Load Detection." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-452735.
Full textAbstract:
For positioning of linear stages in absolute coordinates, there is a general need to find a reference position since the initial one is unknown. This is commonly called homing. To reduce costs and facilitate assembly, homing can be performed without additional sensors, known as sensorless homing. This thesis delves into sensorless homing, specifically with respect to stepper motors, and develops a graphical application for control of them. The commercial technology StallGuard is applied inconjunction with exploration into how it – and sensorless load detectionin general – functions. The resulting graphical application can be used to configure the stepper motors, perform homing using StallGuard, and automatically tune StallGuard to work despite varying conditions. In addition, rudimentary sensorless load detection independent from StallGuard is developed, demonstrating how it could work in practice. Testing shows homing with StallGuard resulting in a position within a ±5μm window in 94% of cases, less than 1/7 the width of an average strand of human hair. Additionally, homing is easily performed with a single button press from the graphical interface, with optional additional configuration available.
9
Bordovský, Tomáš. "Elektronická zátěž s digitálním řízením." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220250.
Full textAbstract:
This diploma thesis deals with analysis and exploration of design options, how to design and produce an electronic load. The paper discussed the possibilities of digital control. It also describes the principles of structural components and there was chosen one type variant which is designed to circuits and printed circuit boards. Moreover, the thesis also include technical drawings of mechanical parts. At the end of this paper, final soulution with measurements and parameters are presented.
10
Gandhi, Shubham. "Out-of-Loop Compensation Method for Op-Amps Driving Heavy Capacitive Loads." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1543.
Full textAbstract:
It is well known that real op-amps do not share most of the desirable characteristics of an ideal one, particularly those of gain and output impedance. When presented with a capacitive load, such as a MOSFET or ADC, feedback in an op-amp circuit can quickly become unstable. This thesis studies and characterizes an op-amp’s output impedance and how its interaction with this type of load creates a parasitic pole which leads to instability. Applying ideas from feedback control theory, a model for studying the problem is developed from which a generalized method for compensating the undesirable circumstance is formulated.
Even in a zero-input state, many real op-amps driving capacitive loads can experience unforced oscillations. A case study is performed with three commonly used devices. First, the output impedance is determined by its dependence on the unity-gain bandwidth, load capacitance, and oscillation frequency. It is fitted into a second-order feedback control model that allows for an analytical study of the problem. It is then shown that a carefully designed passive network can be introduced between the load and op-amp to obtain a properly damped system free of oscillation and well-behaved.
Using a shunt resistor is a known and commonly used method for lowering an op-amp’s output impedance to gain stability. This work considers the converse addition of a series capacitor to instead lower the load capacitance seen by the op-amp, a seemingly complementary method that achieves the same goal. A generalized, composite compensation method is developed that uses both the shunt resistor and series capacitor– a strategy not yet found in literature. Relevant formulas for damping ratio and natural frequency are derived that allow the design of a passive compensation network. Furthermore, tradeoffs between compensation, voltage swing, current consumption, and power usage are considered.
An emphasis is placed on comparing simulated versus real circuits to highlight the fact that any problem is much worse in real-life than in a simulation. SPICE models and programs aim to de-idealize certain device characteristics, but often cannot account for environmental conditions and manufacturing variance. Thus, an importance is placed on experimental verification guided by simulations.
11
Скворчевський, Олександр Євгенович. "Нове покоління гідравлічних приводів для мобільних машин на основі принципу e-LOAD SENSING (e-LS)." Thesis, Харківський національний автомобільно-дорожній університет, 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41789.
Full text
12
Navid-Azarbaijani, Nivad. "Load model and control of residential appliances." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39974.
Full textAbstract:
This thesis is dedicated to the study of load models and control of residential appliances. A load model base on computing an average dwelling augmented by a diversification process is introduced. This model is well-suited for studying the load group's natural and controlled dynamics. To validate this model, extensive simulations are employed. Two different strategies are proposed for the control of residential appliances: (1) aperiodic ON/OFF switching of the appliances; (2) continuous control of the thermostat temperature settings.A mathematical framework based on Pulse Width Modulation theory is developed for the remote ON/OFF switching of residential appliances. Load Management System performs the switching actions on load groups in such a way that the resulting net demand of the appliances matches with a Load Reduction Target. The Load Reduction Target is obtained by modelling load groups as new generation resources into generation scheduling functions. The results of the proposed approach are compared with the results of the current practices and it is shown that the proposed scheme is an effective and flexible method that not only can realize the general form of Load Reduction Targets but also it is capable of error compensation, payback power regulation, switching schedules, incremental update and handling unequal peak powers of load groups.
For continuous control schemes, it is shown that during the control period, diversified states of the appliances do not change drastically and room temperatures within each load group are largely similar. Optimal control strategies are generated by employing Priority List, Linear Programming and Forward Dynamic Programming. The results show a close match between the Load Reduction Target and appliances' demand during control period.
Both methods are efficient and flexible. They allow incremental updating of schedules. Therefore, they are good candidates for use in real time operations.
13
Barros, Neto José Paulo de. "Projeto e implementação de um controle modular HCC para integração de fontes alternativas de energia." Universidade Federal de Santa Maria, 2006. http://repositorio.ufsm.br/handle/1/8478.
Full textAbstract:
The experience of electric energy shortage in 2001 demonstrated that our dependence almost exclusively on hydroelectricity could fetch great problems to Brazil. Thus being, the existence of trustworthy alternatives of energy must exist, at the very least, as a reserve. For this
reason, the perspective of decentralizing the energy production as a form of promoting the socioeconomic
development of remote communities not connected to the public distribution system as well for mass production of electricity, are the motivations of this work. Such situation justified the analysis of performance and development of the integration of diverse types of alternative primary sources by transforming them into current sources as a means of preventing the circulation of current due to voltage differences across the sources. Control of the load voltage
uses the modulation of a secondary load in parallel with a primary load in such a way that current excesses from the current sources are drained only through the secondary load, remaining unchanged the conditions for the primary load. To manage the voltage and current distribution in the main load, a module, dedicated and expandable controller is proposed for hybrid systems of electric energy generation such as those using wind-solar-storage for generation of electric energy in a trustworthy form, unassisted and independent. The proposed integrated system of energy does allow the control and integration of the most usual forms of energy generation such
as hydraulic, wind, storage of energy, specially, in batteries. The control program is also adjusted to integrate other forms of generation, independent of its origin. The control as a whole is based on the algorithm "Hill Climbing Control" (HCC) for individual maximization of the generated power and rotation in each source and regulating the voltage across the load, in order to get the best advantage from the installations. In this dissertation is also shown some practical results about the proposed theory on a prototype of control based on the micro controller PIC18F452 for distribution of energy from a power plant of electric energy generation installed and operating in the CEEMA-UFSM campus. Furthermore, the controller module of power as presented in this work is more useful among others because it allows the use of hybrid electronics and microelectronics that are able of concentrating several circuits in a only "chip", including control
functions for power conversion, A/D devices, program memory, data memory, modules for capture and comparison, timers and PWM modules.A experiência do racionamento de energia elétrica no ano de 2001 no Brasil demonstrou que nossa dependência quase que exclusivamente da hidroeletricidade pode nos trazer grandes problemas. Assim sendo, a existência de alternativas de energia confiáveis deve existir, no mínimo, como reserva. Por esse motivo, a perspectiva da descentralização da produção de energia como forma de promoção do desenvolvimento sócio-econômico de comunidades não atendidas pelas formas convencionais de energia bem como para produção em massa de energias alternativas para grandes sistemas de potência, foram as motivações deste trabalho. A necessidade de um conhecimento melhor da integração entre as fontes de energia. Tais temas justificaram a realização da análise do desempenho e o desenvolvimento de tecnologia para a integração de diversos tipos de fontes alternativas transformadas em fontes de corrente como forma de se evitar a circulação de correntes entre as fontes por diferenças individuais de tensão. O controle da tensão de carga usa a modulação de uma carga secundária em paralelo com outra primária tal que os excessos de corrente das fontes sejam drenados apenas para a carga secundária mantendo-se inalteradas as condições da carga primária. Para gerenciar a distribuição das correntes e a tensão na carga principal, utilizou-se um controlador modular, dedicado e expansível para sistemas híbridos de geração de energia elétrica tais como o eólico-solararmazenamento para geração de energia elétrica de forma confiável, desassistida e autônoma. O sistema de energia desenvolvido permite o controle e o acionamento integrados das formas mais conhecidas de geração de energia envolvendo fontes como a hidráulica, a eólica, armazenadores de energia, em especial, as baterias. O programa de controle é adequado para integrar outras formas de geração, independente de sua origem. O controle como um todo, baseia-se no algoritmo "Hill Climbing Control" (HCC) para maximização individual da potência gerada em cada fonte e para o contingenciamento da rotação pela carga, de modo a se obter o melhor proveito das instalações. Por outro lado, a tensão de saída é modulada através da carga secundária de tal forma a compor uma impedância a ser vista pela fonte de corrente resultante das fontes primárias que estabilize em torno da tensão nominal. Esta dissertação mostra os resultados práticos relativos a um protótipo de controle baseado no PIC18F452 para distribuição de energia a partir de uma central de geração de energia elétrica instalado e funcionando no campus da UFSM. O módulo controlador de potência como se apresenta, presta-se para a utilização dos recursos da eletrônica híbrida e da microeletrônica que podem concentrar num único "chip" diversos circuitos, incluindo conversores de potência, conversores A/D, memória de programa, memória de dados, módulos de captura e comparação, temporizadores e módulos PWM, entre outros.
14
Nguyen, H. M. "Design and Control of a Modular Resonant DC-DC Converter for Point-of-Load Applications." Thesis, University of Colorado at Boulder, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3635889.
Full textAbstract:
Point-of-load (POL) power supplies are high-output-current, low-output-voltage, DC-DC converters that are placed near the electronic components, such as memory chips and microprocessors, on a computer motherboard. They have to meet challenging requirements of high efficiency over a wide load range, and fast transient responses to very dynamic load profiles. The most popular POL topology is based on single-phase or multi-phase buck converters. Buck converters have limitations in large step-down applications due to very low duty cycle requirements for the control MOSFET(s), and relatively high switching losses at high frequencies.
This work proposes a new converter architecture and control method for POL applications—a modular converter based on active-clamp LLC resonant modules, designed to work with an on/off digital controller. The active clamp LLC converter inherits advantages of the standard LLC resonant converter, including soft-switching and 50%-duty-cycle operation of all switching devices. The active clamp addresses the voltage oscillation across the rectifier devices caused by transformer secondary-side leakage inductances and MOSFET output capacitances by clamping the voltage to approximately twice the output dc voltage. In addition, the active clamp helps to reduce the output capacitor current ripple. The converter is well suited for a multiple-parallel-module configuration in which each module, when on, operates at its maximum efficiency. The output voltage is regulated by turning on/off one module in a pulse-width-modulation (PWM) manner while the other modules are either fully on or fully off, depending on the load power demand.
Analysis, modeling, design and control methods are described for the modular active-clamp LLC converter and the results are verified on experimental prototypes. It is found that the proposed converter and the corresponding control approach yield high overall efficiency and fast step-load transient responses. The approach is suitable for single or multi-module high-frequency high-step-down low-voltage point-of-load applications where secondary-side devices and control circuitry can be integrated in a low-voltage CMOS process.
15
Glamheden, Mikael. "Stabilization of Constant Power Loads Using Model Predictive Control." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284685.
Full textAbstract:
This thesis considers stabilization of constant power loads (CPLs) fed by a dcpower source through an input filter, using model predictive control (MPC).Train propulsion systems generally utilize electrical motors whose output torqueis tightly regulated by power converters. Often, these systems behave as CPLs.When a CPL is coupled with an input filter it can lead to a stability problemknown as the negative impedance instability problem. Current state ofthe art regulators deal with this problem using classical frequency domainoptimization-based controllers, such asH1. This thesis instead proposes a linearparameter-varying model predictive controller (LPV-MPC). This advancedcontrol method solves the negative impedance instability problem while alsobeing capable of explicitly addressing signal constraints, which often exist inpower converter applications. The regulator is evaluated in MATLAB/Simulinkas well as in a software-in-the-loop (SIL) simulator. It has furthermore beenrealized in a real-time hardware-in-the-loop (HIL) simulator and tested in apower laboratory. Theoretical results show improved performance over conventionalH1 controllers, in terms of damping and control input use, undercertain operating conditions where the control input is limited. The resultscan be used as a benchmark of theoretical performance limits for design ofother regulators.Detta examensarbete avhandlar stabilisering av konstanta effektlaster (CPL)matade med dc-effekt via ett ingångfilter, med hjälp av modellprediktiv reglering(MPC). Drivsystem i tåg använder vanligen elektriska motorer varsmoment regleras hårt utav effektomriktare. Dessa system beter sig ofta somen CPL. När en CPL sammankopplas med ett ingångfilter kan det leda till ettstabilitetsproblem känt som the negative impedance instability problem (ung.negativ-impedans-instabilitetsproblemet). Dagens främsta regulatorer angriperdetta problem genom att använda klassiska regulatorer baserade på optimeringi frekvensdomän, till exempel H1. I detta examensarbete föreslås iställeten linjär parametervarierande modellprediktiv regulator (LPV-MPC). Dennaavancerade reglermetod löser stabilitetsproblemet och kan samtidigt hanterasignalbegränsningar explicit. Signalbegränsningar är något som ofta finnsi tillämpningar som involverar kraftomriktare. Regulatorn utvärderas i MATLAB/Simulink samt i en mjukvarusimuleringsmiljö. Regulatorn har dessutomförverkligats i en hårvarusimuleringsmiljö och testats i ett labb för kraftelektronik.Teoretiska resultat visar på förbättrad prestanda i jämförelse med konventionellaH1-regulatorer, vad gäller dämpning och användning av styrsignal,i vissa arbetsfall när styrsignalen är begränsad. Resultaten kan användassom ett riktmärke som visar på gränser för teoretisk prestanda vid design avandra regulatorer.
16
Webborn, Ellen. "The dynamics of thermostatically controlled loads for power system frequency control." Thesis, University of Warwick, 2018. http://wrap.warwick.ac.uk/103934/.
Full textAbstract:
Major changes are under way in our power grids. Until very recently, a few hundred, very large, dependable fossil-fuelled power stations were supplying power to consumers whose only role was to use energy whenever they wanted. Today we have wind farms, solar farms, solar panels on millions of roofs, smart metering. Electric vehicles are on the rise and storage technologies are developing rapidly. Achieving a low-carbon, affordable, and secure electricity system, the so-called `energy trilemma,' presents many challenges and opportunities. As energy becomes more dependent on volatile resources such as the wind and sun, flexibility will become increasingly important for maintaining system security at palatable costs. One new source of flexibility could come from domestic appliances. Thermostatically-controlled loads (TCLs), such as fridges, freezers, air-conditioners and hot-water tanks are effectively energy stores that can be adapted to meet the needs of the grid with negligible impact on consumers. By allowing their operating set points to vary (a little) according to the electricity frequency, they could provide a valuable resource to the grid. However, a thorough understanding of their potential to exhibit synchronisation will be needed to understand and mitigate against the potential risks of a decentralised response provider. In this thesis I outline the operation of the electricity grid in Great Britain and describe the existing research into using TCLs for demand-side response. I present a new continuum model for a population of deterministic frequency-sensitive TCLs that is sufficiently tractable to allow for our stability analysis. I also solve for the long-term behaviour of a fully synchronised group of TCLs and analyse its stability to splitting into two groups, and hypothesise about the stability of N groups. Using system data from National Grid, the operation of the GB electricity system is simulated over ten-day periods with, and without, a population of fridges providing frequency response to determine their impact. I find that synchronisation issues should always be expected when the fridge population is identical, but with even very low levels of parameter diversity, such issues are eradicated in our simulations. Given the inherent diversity in a population of TCLs, this research shows that decentralised, deterministic control schemes are a viable option for using TCLs for frequency response, and that such a scheme could provide a valuable resource.
17
Chan, Kristen Y. "MULTIPLE INPUT SINGLE OUTPUT CONVERTER WITH UNEVEN LOAD SHARING CONTROL FOR IMPROVED SYSTEM EFFICIENCY." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2139.
Full textAbstract:
This paper presents the development and study of multiple-input single-output converter (MISO) for the DC House project that utilizes a controller to maximize the overall converter’s efficiency. The premise of this thesis is to create uneven load current sharing between the converters at different loading conditions in order to maximize the efficiency of the overall MISO converter. The goal is to find a proper ratio of current from each converter to the total load current of the MISO system to achieve the greatest efficiency. The Arduino microcontroller is implemented to achieve this goal. The design and operation of the MISO converter with the proposed controller will be explained in this paper. The design and operation of the converter was tested and verified through simulation in LTSpice in addition to hardware implementation. Different ratios of current from each converter were used to fully test the MISO converter. For the 5A and 6A load current, the maximum efficiencies were reached with the 70% / 30% ratio case, with efficiencies of 94.91% and 95.07%, respectively. For 7A load current, the maximum efficiency was reached with the 60% / 40% ratio case, with an efficiency of 94.59%. The results were then compared with those obtained from the equal current sharing cases. For the cases tested, the efficiency of the unequal current sharing outperforms that obtained from the equal current sharing method.
18
Dushku, Mergim, and Ekholm Julius Kokko. "Charge into the Future Grid : Optimizing Batteries to Support the Future Low-Voltage Electrical Grid." Thesis, Linköpings universitet, Fordonssystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157358.
Full textAbstract:
The increase in electric vehicles and photovoltaic power production may introduce problems to the low-voltage distribution grid. With a higher number of electric vehicles, their accumulated charging power might breach the lowest allowed voltage level of the grid. Photovoltaic-modules can on the other hand exceed the highest allowed voltage level, by producing high accumulated power when the solar irradiance is high. Normally, electric distribution companies in Sweden reinforce the existing grid with more resilient infrastructure, such as stronger and larger cables or transformer stations. This is however a costly and time-consuming solution, which could be solved by using alternative means such as already existing resources. This Master's Thesis investigates how smart charging of batteries can support the low-voltage electrical grid with the increase in electric vehicles and photovoltaic power production. To do this, an optimization tool has been developed in Matlab. An existing model of a low-voltage grid is combined with the developed tool, where controllable batteries and photovoltaic-modules can be placed at specific households in the grid. The controllable batteries belong to either electric vehicles or stationary battery systems, and are intended to support the grid by the means of either reducing peak load powers, voltage variations, or a trade-off between them. Furthermore, this thesis investigates the maximum electric vehicle capability for a specific low-voltage electrical grid in Sweden. From the results, it can be concluded that smart charging of batteries can reduce the peak loads as well as voltage variations. The reduction of voltage variations for the entire low-voltage grid is greatest during the summer, when photovoltaic production generally is at its highest. The results also show that a stationary battery system can reduce the voltage variations to a greater extent, compared to an electric vehicle. Also, the introduction of multiple controllable batteries allows further support of the low-voltage grid. Regarding the maximum electric vehicle capability, the results show that the placement of the vehicles and the charging power strongly affect the maximum number of electric vehicles the low-voltage grid can manage.Ökningen av elbilar och elproduktion från solceller kan ge problem i lågspänningsnätet. Med ett ökat antal elbilar kan den sammanlagrade effekten vid laddning underskrida den minsta tillåtna spänningsnivån i nätet. Solpaneler kan däremot leda till att den högsta tillåtna spänningsnivån överskrids, genom att producera en hög sammanlagrad effekt när solstrålningen är som högst. Vanligtvis förstärker elnätsbolag i Sverige det befintliga nätet med motståndskraftigare infrastruktur, såsom kraftigare och större kablar eller transformatorstationer. Detta är dock en kostsam och tidskrävande lösning, som skulle kunna lösas med alternativa medel, till exempel redan existerande resurser. Detta examensarbete undersöker hur smart laddning av batterier kan ge stöd till lågspänningsnätet, med en ökning av elbilar samt solcellsproduktion. För att undersöka detta har ett optimeringsverktyg utvecklats i Matlab. En befintlig modell av ett lågspänningsnät har kombinerats med det utvecklade optimeringsverktyget, där styrbara batterier samt solcellsproduktion kan placeras vid specifika hushåll i elnätet. De styrbara batterierna är antingen elbilar eller stationära batterisystem, och är ämnade till att stödja lågspänningsnätet genom att antingen reducera effekttoppar, spänningsvariationer eller en kompromiss av båda. Vidare undersöker detta examensarbete det maximala antalet elbilar som ett specifikt lågspänningsnät i Sverige kan hantera. Resultaten visar att smart laddning av batterier kan reducera effekttoppar samt spänningsvariationer. Reduceringen av spänningsvariationerna för hela lågspänningsnätet visar sig vara högst under sommaren, vilket är då solcellsproduktionen generellt är som högst. Resultaten visar även att stationära batterisystem kan reducera spänningsvariationer ytterligare, jämfört med en elbil. Att introducera flera styrbara batterier tillåter ett ännu större stöd till lågspänningsnätet. Angående det maximala antalet av elbilar som ett lågspänningsnät kan hantera visade resultaten att placeringen av elbilarna samt laddningseffekten har en stor påverkan.
19
Forbes, Daniel. "Efficiency Performance Improvement Using Parallel DC-DC Converters with a Digital Controller." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/736.
Full textAbstract:
A system to improve efficiency performance of a DC-DC converter is simulated and built. The proposed system combines multiple DC-DC converters in parallel and implements a digital control scheme and load-share controller. A model of the system is developed in MATLAB Simulink and the model demonstrates the improved converter’s efficiency particularly at low load conditions. This simulation is then designed into a hardware system running three DC-DC converters in parallel, controlled by a microcontroller and a load-share controller. The hardware also confirms the simulation results, although some hardware refinements are evident as simulation results are superior. The system is designed to be scalable in the number of converters and the total output power, as well as being DC-DC converter topology-independent. Simulation results show the system maintaining better than 88 % efficiency over almost 90 % of the load range of the system. This system could be implemented where dynamic loads typically occur, such as in electric vehicle charging.
20
Salomonsson, Daniel. "Modeling, Control and Protection of Low-Voltage DC Microgrids." Doctoral thesis, Stockholm : Elektriska energisystem, Electric Power Systems, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4666.
Full text
21
Seyed, Hossein Seyed Sharafedin. "Control of an inverter driven induction motor : optimisation of the efficiency of an inverter driven induction motor over a wide range of loads and speeds by a microprocessor-based slip and power measurement system." Thesis, University of Bradford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358911.
Full text
22
Darden, Kelvin S. "Smart Microgrid Energy Management Using a Wireless Sensor Network." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404560/.
Full textAbstract:
Modern power generation aims to utilize renewable energy sources such as solar power and wind to supply customers with power. This approach avoids exhaustion of fossil fuels as well as provides clean energy. Microgrids have become popular over the years, as they contain multiple renewable power sources and battery storage systems to supply power to the entities within the network. These microgrids can share power with the main grid or operate islanded from the grid. During an islanded scenario, self-sustainability is crucial to ensure balance between supply and demand within the microgrid. This can be accomplished by a smart microgrid that can monitor system conditions and respond to power imbalance by shedding loads based on priority. Such a method ensures security of the most important loads in the system and manages energy by automatically disconnecting lower priority loads until system conditions have improved. This thesis introduces a prioritized load shedding algorithm for the microgrid at the University of North Texas Discovery Park and highlight how such an energy management algorithm can add reliability to an islanded microgrid.
23
Suliman, Ahmad. "A test case for implementing feedback control in a micro hydro power plant." Kansas State University, 2010. http://hdl.handle.net/2097/6847.
Full textAbstract:
Master of ScienceDepartment of Electrical and Computer Engineering
Dwight D. Day
Micro-hydro turbines generate power for small villages and industries in Afghanistan. They usually produce less than 100 kW of power. Currently the flow into the turbine is controlled manually and the voltage is controlled automatically with an electronic load controller. Excess power not used by the village is dumped into a community water heater. For larger sites that have a reservoir and/or large variable load throughout the day and night, the turbine needs to be fitted with an automatic flow control system to conserve water in the reservoir or deal with the variable loads. Large turbines usually use hydraulic governors that automatically adjust the flow of water into the turbine. For micro-hydro sized plants this method would be too expensive and be difficult to build and maintain locally. For this reason, a 3 phase AC induction motor will be used to move the internal flow control valve of the turbine. Because a sudden change in load is possible (30 – 40%) for micro-hydro plants, the electronic load controller will also be needed to respond to quick changes in load so that the village voltage does not exceed 220V. This report documents the process of building a test system comprising of a dynamic resistive load, microcontroller controlled resistive load, a three phase AC generator and a DC Motor. Where the dynamic resistive load represents the load of the village, the computer controlled resistive load would represent the community water heater, the three phase AC generator represents the Generator on site and the DC Motor together with its DC input voltage would emulate the turbine and its water flow respectively. The DC input voltage would be also controlled with a PWM signal through a delay loop to represent the water gate delay effects on the turbine as close as possible. With this, it would be possible to completely build and test a control system that emulates the dynamics of a water turbine generator.
24
Klein, Rafael Luís. "Carga eletrônica CA programável com regeneração de energia." Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/1856.
Full textAbstract:
Made available in DSpace on 2016-12-12T17:38:31Z (GMT). No. of bitstreams: 1
RAFAEL LUIS KLEIN.pdf: 5183881 bytes, checksum: c72755a48cf9cf0f75f8a8c73a4fe23c (MD5)
Previous issue date: 2012-02-28Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This study is about the design and implementation of a programmable ac electronic load with power regeneration capability. This equipment can be used in burn-in tests and at the development of switching power supplies. The main advantages of this kind of emulator is the power consumption reduction, lower volume compared to conventional loads, no cooling additional costs, peak load reduction, agility and easiness of non-linear and linear current load profile configuration. The emulator is composed by a current controlled rectifier, which drains from the equipment under test the desired current profile, and a current controlled inverter connected to the grid, which is responsible for power regenerating. Initially, a study for applications of the emulator is shown, where standards and tests requirements are analyzed. Afterward, the power structure of the emulator is shown. After that, the high frequencies filters are analyzed and designed, the circuit mathematical models are obtained, then a control project methodology based on frequency is shown. Simulation results complement the study and prove the applied methodology. Finally, a 4.5kVA prototype is developed and tested. The experimental results are analyzed and discussed.
Este estudo trata do projeto e implementação de uma carga eletrônica ca programável com regeneração de energia. Este equipamento pode ser empregado nos testes de Burn-in ou ensaios de desenvolvimento de fontes chaveadas. Dentre as principais vantagens na utilização do emulador, destacam-se: redução do consumo de energia elétrica, redução da área ocupada pelos dispositivos de testes com cargas convencionais, redução dos custos de instalação e de consumo de energia dos sistemas de refrigeração, redução dos picos de demanda de potência, facilidade e agilidade na configuração dos mais variados tipos de cargas lineares e nãolineares. O emulador é formado por um retificador controlado em corrente, responsável por drenar do EST o perfil de corrente desejado, e um inversor controlado em corrente, responsável pela injeção de corrente na rede elétrica, em contra-fase com a tensão, caracterizando a regeneração de energia. Inicialmente é apresentado um estudo das aplicações para o emulador, onde são analisadas as normas vigentes para testes de equipamentos com carga. Em seguida são apresentadas as estruturas de potência do emulador. Após isto são analisados e projetados os filtros de alta frequência, obtidos os modelos matemáticos dos circuitos necessários para o projeto dos controladores, assim como é apresentada uma metodologia de projeto de controle baseado na resposta em frequência. Resultados de simulação complementam o estudo e comprovam a metodologia apresentada. Para finalizar, um protótipo de 4,5kVA é desenvolvido e ensaiado, onde os resultados experimentais são analisados e discutidos.
25
HSU, CHUN-NUNG, and 許峻農. "Remote Control and Monitor for DC Electronic Load." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/73761627244484689242.
Full textAbstract:
碩士明新科技大學
電機工程系碩士在職專班
103
The theme of this thesis is to integrate a Bluetooth module, a microcontroller system, and a DC electronic load into a remotely controlled DC electronic load. The thesis begins with the study of the principles of the DC electronic load, Bluetooth module, and microcontroller, and then combines them together into a complete system with the verification of completeness and feasibility through practical applications. The resulting system can remotely control and monitor a DC electronic tensile load current with a microcontroller. Either smart phones (mobile phones) or tablet PCs can be used as the main control interface to transfer commands and data to and from the microcontroller system via the Bluetooth module. In the aspect of remotely controlled DC electronic load, the main interface can control the tensile load current of the DC electronic load. In the aspect of monitoring DC load current, the main interface can display the amount of tensile load current in the DC electronic load detected by the microcontroller system transmitted by the remote Bluetooth module.
26
Cardoso, Andre Daniel Magalhaes. "use of active load control for congestion management." Dissertação, 2013. https://repositorio-aberto.up.pt/handle/10216/69243.
Full text
27
Cardoso, Andre Daniel Magalhaes. "use of active load control for congestion management." Master's thesis, 2013. https://repositorio-aberto.up.pt/handle/10216/69243.
Full text
28
Chisholm, Robin Lynn. "Emergency physician documentation quality and cognitive load : comparison of paper charts to electronic physician documentation." Thesis, 2014. http://hdl.handle.net/1805/5809.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)Reducing medical error remains in the forefront of healthcare reform. The use of health information technology, specifically the electronic health record (EHR) is one attempt to improve patient safety. The implementation of the EHR in the Emergency Department changes physician workflow, which can have negative, unintended consequences for patient safety. Inaccuracies in clinical documentation can contribute, for example, to medical error during transitions of care. In this quasi-experimental comparison study, we sought to determine whether there is a difference in document quality, error rate, error type, cognitive load and time when Emergency Medicine (EM) residents use paper charts versus the EHR to complete physician documentation of clinical encounters. Simulated patient encounters provided a unique and innovative environment to evaluate EM physician documentation. Analysis focused on examining documentation quality and real-time observation of the simulated encounter. Results demonstrate no change in document quality, no change in cognitive load, and no change in error rate between electronic and paper charts. There was a 46% increase in the time required to complete the charting task when using the EHR. Physician workflow changes from partial documentation during the patient encounter with paper charts to complete documentation after the encounter with electronic charts. Documentation quality overall was poor with an average of 36% of required elements missing which did not improve during residency training. The extra time required for the charting task using the EHR potentially increases patient waiting times as well as clinician dissatisfaction and burnout, yet it has little impact on the quality of physician documentation. Better strategies and support for documentation are needed as providers adopt and use EHR systems to change the practice of medicine.
29
Gouveia, Clara Sofia Teixeira. "Experimental validation of microgrids: exploiting the role of plug-in electric vehicles, active load control and micro-generation units." Tese, 2015. https://repositorio-aberto.up.pt/handle/10216/78808.
Full text
30
Gouveia, Clara Sofia Teixeira. "Experimental validation of microgrids: exploiting the role of plug-in electric vehicles, active load control and micro-generation units." Doctoral thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/78808.
Full text
31
Banerjee, Debmalya. "Load Commutated SCR Current Source Inverter Fed Induction Motor Drive With Sinusoidal Motor Voltage And Current." Thesis, 2008. http://hdl.handle.net/2005/744.
Full textAbstract:
This thesis deals with modeling, simulation and implementation of Load Commutated SCR based current source Inverter (LCI) fed squirrel cage induction motor drive with sinusoidal voltage and sinusoidal current. In the proposed system, the induction motor is fed by an LCI. A three level diode clamped voltage source inverter (VSI) is connected at the motor terminal with ac chokes connected in series with it. The VSI currents are controlled in such a manner that it injects the reactive current demanded by the induction motor and the LCI for successful commutation of the SCRs in the LCI. Additionally, it absorbs the harmonic frequency currents to ensure that the induction motor draws sinusoidal current. As a result, the nature of the motor terminal voltage is also sinusoidal.
The concept of load commutation of the SCRs in the LCI feeding an induction motor load is explained with necessary waveforms and phasor diagrams. The necessity of reactive compensation by the active filter connected at the motor terminal for the load commutation of the thyristors, is elaborated with the help of analytical equations and phasor diagrams. The requirement of harmonic compensation by the same active filter to achieve sinusoidal motor current and motor voltage, is also described. Finally, to achieve the aforementioned induction motor drive, the VA ratings of the active filter (VSI) and the CSI with respect to VA rating of the motor, are determined theoretically. The proposed drive scheme is simulated under idealized condition. Simulation results show good steady state and dynamic response of the drive system. Load commutation of the SCRs in the LCI and the sinusoidal profile of motor current and voltage, have been demonstrated.
As in LCI fed synchronous motor drives, a special mode of operation is required to run up the induction motor from standstill. As the SCRs of the LCI are load commutated, they need motor terminal voltages for commutation. At standstill these voltages are zero. So, a starting strategy has been proposed and adopted to start the motor with the aid of the current controlled VSI to accelerate until the motor terminal voltages are high enough for the commutation of the SCRs in the LCI.
The proposed drive is implemented on an experimental setup in the laboratory. The IGBT based three level diode clamped VSI has been fabricated following the design of the standard module in the laboratory. A generalized digital control platform is also developed using a TMS320F2407A DSP. Two, three phase thyristor bridges with necessary firing pulse circuits have been used as the phase controlled rectifier and the LCI respectively. Appropriate protection scheme for such a drive is developed and adopted to operate the drive. Relevant experimental results are presented. They are observed to be in good agreement with the simulation results.
The effect of capacitors connected at the output of the LCI in the commutation process of the SCRs in the LCI is studied and analyzed. From the analysis, it is understood that the capacitors form a parallel resonating pair with filter inductor and the motor leakage inductance, which results in an undesired oscillation in the terminal voltage during each of the commutation intervals leading to commutation failure. So, in the final system, the capacitors are removed to eliminate any chance of commutation failure of the SCRs in the LCI. It is shown by experiment that the commutation of the SCRs takes place reliably in the absence of the capacitors also. The commutation process is studied and analyzed without the capacitors to understand the motor terminal voltage waveform of the experimental results.
32
Kuo, Chao-Shun, and 郭肇勳. "Using an FPGA Chip to Design a High-speed Control System for Multiple Sets of Programmable DC Electronic Loads." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/62854311717059008126.
Full textAbstract:
碩士輔仁大學
電子工程學系
95
The purpose of this paper is to design a high-speed control system for programmable DC electronic loads by combining an FPGA chip and a MCU (microcontroller unit). VHDL (Very High Speed Integrated Circuit Hardware Description Language) is used to devise a configurable control mechanism for a DCS (dynamic control system). Utilizing a programmable design and effective formulation in memory modules to design the commutation interface between MCU and FPGA chip, we replace the hardware design by the software controls of the peripheral circuits that add to the elasticity of the circuit design and lessen the resource demand by the MCU, to further simplify the procedure of the software design and to improve the design efficiency. By means of simulation and verification using the FPGA chip as our development tool we carry out experiments with the dynamic control system for programmable DC electronic loads. Our design provides the advantage of speeding the process of the hardware carrying out the concurrent output control for many peripheral circuits, allowing the setting of the programmable parameters of 100 sets to send out each datum synchronously when the Run Program Mode is in high data rate. This high data rate provides the timing demand of many peripheral circuits which are controlled by a time-sharing process. The shortest duration of each set reaches 25 µS, using our design which provides a constant current to sink stably under the Constant Load Mode with the error rate under 1%. The Dynamic Load Mode provides accuracy of duration, and switching frequency can reach 20 KHz.
33
Radic, Aleksandar. "Practical Volume-reduction Strategies for Low-power High-frequency Switch Mode Power Supplies." Thesis, 2014. http://hdl.handle.net/1807/44131.
Full textAbstract:
The miniaturization of dc–dc switch-mode power supplies (SMPS) is of a key importance in volume-sensitive portable devices, such as cell phones, tablet computers, and digital cameras. In these systems, multiple SMPS are required to provide well regulated voltage and power to various electronic components such as the central processing unit (CPU) and random-access memory (RAM). The combined volume, weight, and surface area footprint of these SMPS is usually the largest component.
Traditionally, SMPS volume reduction has been achieved through increased switching frequencies; however, for power-sensitive applications this is undesirable due to the increased switching losses. This thesis presents two alternative, power-efficient, SMPS miniaturization methods: one control and one topology based.
The presented controller recovers from load transients with virtually minimum possible output voltage deviation, reducing the reactive component size. The controller utilizes a simple algorithm, requiring no knowledge of the converter parameters and virtually no processing power. The simplicity of the control concept enabled the design of an area and power efficient integrated circuit (IC) implementation.
The entire IC is implemented in a CMOS 0.18µm process on a 0.26 mm2 silicon area, which is comparable to the state-of-the-art analog solutions. For the experimental system the deviation (output capacitor size) is about four times smaller than that of a fast PID compensator having a 1/10th of the switching frequency bandwidth.
The second solution is a complementary converter topology that has a smaller output filter volume, improved dynamic response, and lower switching losses compared to the state-of-the-art solutions. To reduce the volume and switching losses, the input-to-output voltage difference is decreased with a capacitive attenuator that replaces the input filter capacitor and has approximately the same volume. Both the attenuator and the downstream buck converter share the same set of switches, minimizing conduction losses. A single multi-mode digital controller governs operation of both stages, seamlessly regulating the output and input center-tap voltages. Experiments with a 5–1.5-V, 2.5-A, 1-MHz prototype show that, compared to the conventional buck, the merged topology has 43% smaller inductor, 36% smaller output capacitor, up to 30% lower power losses, and a 25% faster transient response.