Dissertations / Theses: 'Proportional Integral Resonant controller'

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Chopra, Shubham. "Evolved Design of a Nonlinear Proportional Integral Derivative (NPID) Controller." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/512.

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This research presents a solution to the problem of tuning a PID controller for a nonlinear system. Many systems in industrial applications use a PID controller to control a plant or the process. Conventional PID controllers work in linear systems but are less effective when the plant or the process is nonlinear because PID controllers cannot adapt the gain parameters as needed. In this research we design a Nonlinear PID (NPID) controller using a fuzzy logic system based on the Mamdani type Fuzzy Inference System to control three different DC motor systems. This fuzzy system is responsible for adapting the gain parameters of a conventional PID controller. This fuzzy system's rule base was heuristically evolved using an Evolutionary Algorithm (Differential Evolution). Our results show that a NPID controller can restore a moderately or a heavily under-damped DC motor system under consideration to a desired behavior (slightly under-damped).

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Chin, Hui Hui. "ALL DIGITAL DESIGN AND IMPLEMENTAION OF PROPORTIONAL-INTEGRAL-DERIVATIVE (PID) CONTROLLER." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_theses/272.

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Due to the prevalence of pulse encoders for system state information, an all-digital proportional-integral-derivative (ADPID) is proposed as an alternative to traditional analog and digital PID controllers. The basic concept of an ADPID stems from the use of pulse-width-modulation (PWM) control signals for continuous-time dynamical systems, in that the controllers proportional, integral and derivative actions are converted into pulses by means of standard up-down digital counters and other digital logic devices. An ADPID eliminates the need for analog-digital and digital-analog conversion, which can be costly and may introduce error and delay into the system. In the proposed ADPID, the unaltered output from a pulse encoder attached to the systems output can be interpreted directly. After defining a pulse train to represent the desired output of the encoder, an error signal is formed then processed by the ADPID. The resulting ADPID output or control signal is in PWM format, and can be fed directly into the target system without digital-to-analog conversion. In addition to proposing an architecture for the ADPID, rules are presented to enable control engineers to design ADPIDs for a variety of applications.

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McCluskey, Emmet Gerard. "Rule-based automatic PID controller tuning." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335433.

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Bhambhani, Varsha. "Optimal Fractional Order Proportional And Integral Controller For Processes With Random Time Delays." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/246.

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This thesis developed a new practical tuning method for fractional order proportional and integral controllers (FO-PI) for varying time-delay systems like networked control systems (NCS), sensor networks, etc. Based on previously proposed FO-PI controller tuning rules using fractional Ms constrained integral gain optimization (F-MIGO), simultaneous maximization of the jitter margin and integrated time weighted absolute error (ITAE) performance for a set of hundred gain delay time-constant (KLT) systems having different time-constants and time-delay values are achieved. A multi-objective optimization algorithm is used to simultaneously maximize the ITAE factor and jitter margin of the plants at initial F-MIGO gain parameters. The new values of controller gain parameters are generalized to give a new set of optimal fractional order proportional integral (OFOPI) tuning rules such that the jitter margin and system performance of closed-loop KLT systems are maximized and yet the closed-loop feedback system is stable. This is further tested and verified by simulation techniques. Comparisons are made with other existing proportional integral derivative (PID) and fractional order proportional integral (PI) tuning rules to prove the efficiency of the new technique. It is further shown that OFOPI tuning rules perform better than traditional tuning methods for lag-dominated FOPDT systems, because it can take the varying time-delay better into account. The tuning method is modified to work with discrete-time controllers in the context of NCSs. Furthermore, experimental results in a NCS platform, Stand-alone Smart Wheel (omnidirectional networked control robot wheel), are reported using the tuning rules developed in this thesis. The optimization tuning method performed almost equally well in practice as in simulations. The thesis also shows that the tuning rule development procedure for OFOPI is not only valid for FOPDT systems but is also applicable for other general classes of plants which could be reduced to first order plant systems. Temperature control in heat flow apparatus and water-level control in a coupled tank system using FO-PI tuning rules are other major contributions of this thesis work.

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Cong, Jun. "Enhancing TCP traffic flow performance with a proportional and integral rate controller: Theory, design, and performance evaluation." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26615.

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This thesis proposes a new network traffic congestion control algorithm---the PIR (Proportional and Integral Rate) controller. It is designed to overcome the shortcomings of RED and some other related AQM (Active Queue Management) techniques developed in recent years. That is to avoid unnecessary packet losses and stabilize the queue length in the router. It can also prevent the throughput reduction in the presence of wireless links. We proved the stability of the PIR controller theoretically and conducted the performance analysis and comparison for the PIR controller and some other common traffic congestion control schemes.

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Gogoi, Manoj. "Proportional-Integral-Derivative (PID) controller design for robust stability of arbitrary order plants with time-delay and additive uncertainty." Thesis, Wichita State University, 2010. http://hdl.handle.net/10057/3478.

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In the process control industry, majority of control loops are based on Proportional-Integral-Derivative (PID) controllers. The basic structure of the PID controllers makes it easy to regulate the process output. Design methods leading to an optimal and effective operation of the PID controllers are economically vital for process industries. Robust control has been a recent addition to the field of control engineering that primarily deals with obtaining system robustness in presences of uncertainties. In this thesis, a graphical design method for obtaining the entire range of PID controller gains that robustly stabilize a system in the presence of time delays and additive uncertainty is introduced. This design method primarily depends on the frequency response of the system, which can serve to reduce the complexities involved in plant modeling. The fact that time-delays and parametric uncertainties are almost always present in real time processes makes our controller design method very vital for process control. We have applied our design method to a DC motor model with a communication delay and a single area non-reheat steam generation unit. The results were satisfactory and robust stability was achieved for the perturbed plants. Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

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Samaranayake, Lilantha. "Distributed control of electric drives via Ehernet." Licentiate thesis, KTH, Electrical Systems, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1656.

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This report presents the work carried out aiming towardsdistributed control of electric drives through a networkcommunication medium with temporal constraints, i.e, Ethernet.A general analysis on time delayed systems is carried out,using state space representation of systems in the discretetime domain. The effect of input time delays is identified andis used in the preceding controller designs. The main hardwareapplication focused in this study is a Brushless DC servomotor, whose speed control loop is closed via a 10 MbpsSwitched Ethernet network. The speed control loop, which isapproximately a decade slower than the current control loop, isopened and interfaced to the network at the sensor/actuatornode. It is closed at the speed controller end at another nodein the same local area network (LAN) forming a distributedcontrol system (DCS).The Proportional Integral (PI) classical controller designtechnique with ample changes in parameter tuning suitable fortime delayed systems is used. Then the standard Smith Predictoris tested, modified with the algebraic design techniqueCoefficient Diagram Method (CDM), which increases the systemdegrees of freedom. Constant control delay is assumed in thelatter designs despite the slight stochastic nature in thetiming data observations. Hence the poor transient performanceof the system is the price for the robustness inherited to thespeed controllers at the design stage. The controllability andobservability of the DCS may be lost, depending on the range inwhich the control delay is varying. However a state feedbackcontroller deploying on-line delay data, obtained by means ofsynchronizing the sensor node and controller node systemclocks, results in an effective compensation scheme for thenetwork induced delays. Hence the full state feedbackcontroller makes he distributed system transient performanceacceptable for servo applications with the help of poleplacement controller design.Further, speed synchronizing controllers have been designedsuch that a speed fluctuation caused by a mechanical loadtorque disturbance on one motor is followed effectively by anyother specified motor in the distributed control network with aminimum tracking or synchronizing error. This type ofperformance is often demanded in many industrial applicationssuch as printing, paper, bagging, pick and place and materialcutting.Keywords:Brushless DC Motor, Control Delay, DistributedMotion Control Systems, Proportional Integral Controller, SmithPredictor, Speed Synchronization, State Feedback Controller,Stochastic Systems, Switched-Ethernet, Synchronizing Error,Time Delayed Systems, Tracking Error

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Park, Sung Yeul. "A Wide Range and Precise Active and Reactive Power Flow Controller for Fuel Cell Power Conditioning Systems." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28645.

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This dissertation aims to present a detailed analysis of the grid voltage disturbance in frequency domain for the current control design in the grid-tie inverter applications and to propose current control techniques in order to minimize its impact and maximize feasibility of the power conditioning system in distributed generations. Because the grid voltage is constantly changing, the inverter must be able to response to it. If the inverter is unable to respond properly, then the grid voltage power comes back to the system and damages the fuel cell power conditioning systems. A closed-loop dynamic model for the current control loop of the grid-tie inverter has been developed. The model explains the structure of the inverter admittance terms. The disturbance of the grid voltages has been analyzed in frequency domain. The admittance compensator has been proposed to prevent the grid voltage effect. The proposed lead-lag current control with admittance compensator transfers current properly without system failure. In order to get rid of the steady-state error of the feedback current, a proportional-resonant controller (PR) has been adopted. A PR control with admittance compensation provides great performance from zero power to full power operation. In addition, active and reactive power flow controller has been proposed based on the PR controller with admittance compensation. The proposed active and reactive power flow control scheme shows a wide range power flow control from pure leading power to pure lagging power. Finally, the proposed controller scheme has been verified its feasibility in three phase grid-tie inverter applications. First of all, a half-bridge grid-tie inverter has been designed with PR controller and admittance compensation. Then three individual grid-tie inverters has been combined and produced three phase current to the three phase grid in either balanced condition or unbalanced condition. The proposed control scheme can be applied not only single phase grid-tie inverter application, but also three phase grid-tie inverter application. This research can be applicable to the photovoltaic PCS as well. This technology makes renewable energy source more plausible for distributed generations. Ph. D.

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Selby, Normajean. "STATE-VARIABLE FEEDBACK CONTROL OF A MAGNETICALLY SUSPENDED CENTRIFUGAL BLOOD PUMP." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1185567515.

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Jebelli, Ali. "Design of an Autonomous Underwater Vehicle with Vision Capabilities." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35358.

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In the past decade, the design and manufacturing of intelligent multipurpose underwater vehicles has increased significantly. In the wide range of studies conducted in this field, the flexibility and autonomy of these devices with respect to their intended performance had been widely investigated. This work is related to the design and manufacturing of a small and lightweight autonomous underwater vehicle (AUV) with vision capabilities allowing detecting and contouring obstacles. It is indeed an exciting challenge to build a small and light submarine AUV, while making tradeoffs between performance and minimum available space as well as energy consumption. In fact, due to the ever-increasing in equipment complexity and performance, designers of AUVs are facing the issues of limited size and energy consumption. By using a pair of thrusters capable to rotate 360o on their axis and implementing a mass shifter with a control loop inside the vehicle, this later can efficiently adapt its depth and direction with minimal energy consumption. A prototype was fabricated and successfully tested in real operating conditions (in both pool and ocean). It includes the design and embedding of accurate custom multi-purpose sensors for multi-task operation as well as an enhanced coordinated system between a high-speed processor and accustomed electrical/mechanical parts of the vehicle, to allow automatic controlling its movements. Furthermore, an efficient tracking system was implemented to automatically detect and bypass obstacles. Then, fuzzy-based controllers were coupled to the main AUV processor system to provide the best commands to safely get around obstacles with minimum energy consumption. The fabricated prototype was able to work for a period of three hours with object tracking options and five hours in a safe environment, at a speed of 0.6 m/s at a depth of 8 m.

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Jowkar, Saeid. "The Application of Programmable Logic Controller (PLC) to Control Temperature in Cold-room Based on TIA PORTAL Software." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.

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A temperature sensor is a device to measure the temperature through an electrical signal. It requires a thermocouple or resistance temperature detectors (RTD) and will interface with a programmable logic controller (PLC). A temperature transmitter is a device that connects to a temperature sensor to transmit the signal elsewhere for monitoring and control purposes that its role is to convert the temperature sensor's signal to a 0-10V DC voltage in the PLC. The PLC voltage signal setting is compared to the temperature deviation after the Proportional Integral Derivative (PID) operation. Then, the system will issue a temperature control signal to achieve the cooling system voltage control so that it implements continuous monitoring and temperature control. The temperature control system in the industrial field has a certain value that it is an important factor for controlling temperature. A certain value of the temperature of the desired environment has to be set with a minimum and maximum set-point temperature which is suitable for that environment and the set-point value can be variable and can be changed with Human Machine Interface (HMI) easily.

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Holgersson, Anton, and Johan Gustafsson. "Trajectory Tracking for Automated Guided Vehicle." Thesis, Linköpings universitet, Reglerteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176423.

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The purpose of this thesis is to investigate different control strategies on a differential drive vehicle. The vehicle should be able to drive in turns at high speed and slowly when it should park next to a charger. In both these cases, good precision in both orientation and distance to the path is important. A PID and an LQ controller have been implemented for this purpose. The two controllers were first implemented in a simulation environment. After implementing the controllers on the system itself, tests to evaluate the controllers were made to imitate real-life situations. This includes tests regarding driving with different speeds in different turns, tests with load distributions, and tests with stopping accuracy. The existing controller on the system was also tested and compared to the new controllers. After evaluating the controllers, it was stated that the existing controller was the most robust. It was not affected much by the load distribution compared to the new controllers. However, the LQ controller was slightly better in most cases, even though it was highly affected by the load distribution. The PID controller performed best regarding stopping accuracy but was the least robust controller by the three. Since the existing controller has a similar performance as the LQ controller but is more robust, the existing controller was chosen as the best one.

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Catata, Elmer Osman Hancco. "Controlador PI FUZZY aplicado ao controle direto de potência do gerador de relutância variável de 12/8 conectado à rede elétrica." reponame:Repositório Institucional da UFABC, 2016.

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Orientador: Prof. Dr. José Luis Azcue Puma Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2016. Este trabalho apresenta o controle direto de potencia do gerador de relutancia variavel de 12/8 utilizando o controlador fuzzy PI auto-ajustavel e o controle vetorial do inversor conectado à rede eletrica. Inicialmente são estudados os principios de operação da maquina e a topologia do conversor eletronico de potencia que sera utilizado para aciona-lo. Usando o software de simulaçãoMatlab/Simulink é implementado o modelo da maquina de relutancia variavel utilizando as curvas caracteristicas, de corrente e torque, que foram extraídas utilizando dados experimentais. Utilizando o modelo da maquina é projetado o controlador de velocidade para sua operação no modo motor. Tambem sera projetado o controlador de potência PI utilizando o modelo estimado do sistema de conversão de energia eólica. A partir dos ganhos do controlador PI é projetado o controlador fuzzy PI autoajustavel com o objetivo de melhorar a resposta em regime permanente da potencia controlada. A potencia gerada pelo gerador de relutancia variavel é injetada à rede eletrica, atraves do controle independente das potencias ativa e reativa, para este proposito é utilizado um conversor trifasico de dois níveis. Na parte experimental deste trabalho foi implementado o controle de corrente por histerese para maquina operando no modo motor, posteriormente foi implementado o controle de corrente e controle da tens~ao no barramento CC para a máquina operando no modo gerador. Os resultados de simulação e experimentais se mostraram coerentes validando os controladores propostos. This work presents the direct power control of the switched reluctance generator of 12/8 using the self-tuning fuzzy PI controller and the vector control for inverter connected to the grid. Initially, the machine's operating principles and the topology of the power electronics converter used to drive this machine are studied. The model of switched reluctance machine is implemented in Matlab/Simulink simulation software using the characteristic curves of current and torque extracted using experimental data. Using the machine's model, It is designed the speed controller for its operation in motor mode. Also, the PI controller is designed for the power control loop based on the estimation of the wind energy conversion system. Using the gains of the PI controller, It is designed the self-tuning fuzzy PI controller, in order to improve the steady state response of the power control loop. The power generated by the switched reluctance generator is injected into the power grid through the independent control of active and reactive power, for this purpose is used a three-phase two level converter. In the experimental part of this work was implemented the hysteresis current control for machine operating in motor mode, also, It was implemented the current and DC bus voltage control for the machine operating in generator mode. The simulation and experimental results were proved consistent and these results validate the proposed controllers.

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Enbiya, Saleh A. "Automatic Control Strategies of Mean Arterial Pressure and Cardiac Output. MIMO controllers, PID, internal model control, adaptive model reference, and neural nets are developed to regulate mean arterial pressure and cardiac output using the drugs sodium Nitroprusside and dopamine." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/13421.

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High blood pressure, also called hypertension is one of the most common worldwide diseases afflicting humans and is a major risk factor for stroke, myocardial infarction, vascular disease, and chronic kidney disease. If blood pressure is controlled and oscillations in the hemodynamic variables are reduced, patients experience fewer complications after surgery. In clinical practice, this is usually achieved using manual drug delivery. Given that different patients have different sensitivity and reaction time to drugs, determining manually the right drug infusion rates may be difficult. This is a problem where automatic drug delivery can provide a solution, especially if it is designed to adapt to variations in the patient’s conditions. This research work presents an investigation into the development of abnormal blood pressure (hypertension) controllers for postoperative patients. Control of the drugs infusion rates is used to simultaneously regulate the hemodynamic variables such as the Mean Arterial Pressure (MAP) and the Cardiac Output (CO) at the desired level. The implementation of optimal control system is very essential to improve the quality of patient care and also to reduce the workload of healthcare staff and costs. Many researchers have conducted studies earlier on modelling and/or control of abnormal blood pressure for postoperative patients. However, there are still many concerns about smooth transition of blood pressure without any side effect. The blood pressure is classified in two categories: high blood pressure (Hypertension) and low blood pressure (Hypotension). The hypertension often occurred after cardiac surgery, and the hypotension occurred during cardiac surgery. To achieve the optimal control solution for these abnormal blood pressures, many methods are proposed, one of the common methods is infusing the drug related to blood pressure to maintain it at the desired level. There are several kinds of vasodilating drugs such as Sodium Nitroprusside (SNP), Dopamine (DPM), Nitro-glycerine (NTG), and so on, which can be used to treat postoperative patients, also used for hypertensive emergencies to keep the blood pressure at safety level. A comparative performance of two types of algorithms has been presented in chapter four. These include the Internal Model Control (IMC), and Proportional-Integral-Derivative (PID) controller. The resulting controllers are implemented, tested and verified for three sensitivity patient response. SNP is used for all three patients’ situation in order to reduce the pressure smoothly and maintain it at the desire level. A Genetic Algorithms (GAs) optimization technique has been implemented to optimise the controllers’ parameters. A set of experiments are presented to demonstrate the merits and capabilities of the control algorithms. The simulation results in chapter four have demonstrated that the performance criteria are satisfied with the IMC, and PID controllers. On the other hand, the settling time for the PID control of all three patients’ response is shorter than the settling time with IMC controller. Using multiple interacting drugs to control both the MAP and CO of patients with different sensitivity to drugs is a challenging task. A Multivariable Model Reference Adaptive Control (MMRAC) algorithm is developed using a two-input, two-output patient model. Because of the difference in patient’s sensitivity to the drug, and in order to cover the wide ranges of patients, Model Reference Adaptive Control (MRAC) has been implemented to obtain the optimal infusion rates of DPM and SNP. This is developed in chapters five and six. Computer simulations were carried out to investigate the performance of this controller. The results show that the proposed adaptive scheme is robust with respect to disturbances and variations in model parameters, the simulation results have demonstrated that this algorithm cannot cover the wide range of patient’s sensitivity to drugs, due to that shortcoming, a PID controller using a Neural Network that tunes the controller parameters was designed and implemented. The parameters of the PID controller were optimised offline using Matlab genetic algorithm. The proposed Neuro-PID controller has been tested and validated to demonstrate its merits and capabilities compared to the existing approaches to cover wide range of patients. Libyan Ministry of Higher Education scholarship

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Enbiya, Saleh Abdalla. "Automatic control strategies of mean arterial pressure and cardiac output : MIMO controllers, PID, internal model control, adaptive model reference, and neural nets are developed to regulate mean arterial pressure and cardiac output using the drugs Sodium Nitroprusside and Dopamine." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/13421.

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High blood pressure, also called hypertension is one of the most common worldwide diseases afflicting humans and is a major risk factor for stroke, myocardial infarction, vascular disease, and chronic kidney disease. If blood pressure is controlled and oscillations in the hemodynamic variables are reduced, patients experience fewer complications after surgery. In clinical practice, this is usually achieved using manual drug delivery. Given that different patients have different sensitivity and reaction time to drugs, determining manually the right drug infusion rates may be difficult. This is a problem where automatic drug delivery can provide a solution, especially if it is designed to adapt to variations in the patient’s conditions. This research work presents an investigation into the development of abnormal blood pressure (hypertension) controllers for postoperative patients. Control of the drugs infusion rates is used to simultaneously regulate the hemodynamic variables such as the Mean Arterial Pressure (MAP) and the Cardiac Output (CO) at the desired level. The implementation of optimal control system is very essential to improve the quality of patient care and also to reduce the workload of healthcare staff and costs. Many researchers have conducted studies earlier on modelling and/or control of abnormal blood pressure for postoperative patients. However, there are still many concerns about smooth transition of blood pressure without any side effect. The blood pressure is classified in two categories: high blood pressure (Hypertension) and low blood pressure (Hypotension). The hypertension often occurred after cardiac surgery, and the hypotension occurred during cardiac surgery. To achieve the optimal control solution for these abnormal blood pressures, many methods are proposed, one of the common methods is infusing the drug related to blood pressure to maintain it at the desired level. There are several kinds of vasodilating drugs such as Sodium Nitroprusside (SNP), Dopamine (DPM), Nitro-glycerine (NTG), and so on, which can be used to treat postoperative patients, also used for hypertensive emergencies to keep the blood pressure at safety level. A comparative performance of two types of algorithms has been presented in chapter four. These include the Internal Model Control (IMC), and Proportional-Integral-Derivative (PID) controller. The resulting controllers are implemented, tested and verified for three sensitivity patient response. SNP is used for all three patients’ situation in order to reduce the pressure smoothly and maintain it at the desire level. A Genetic Algorithms (GAs) optimization technique has been implemented to optimise the controllers’ parameters. A set of experiments are presented to demonstrate the merits and capabilities of the control algorithms. The simulation results in chapter four have demonstrated that the performance criteria are satisfied with the IMC, and PID controllers. On the other hand, the settling time for the PID control of all three patients’ response is shorter than the settling time with IMC controller. Using multiple interacting drugs to control both the MAP and CO of patients with different sensitivity to drugs is a challenging task. A Multivariable Model Reference Adaptive Control (MMRAC) algorithm is developed using a two-input, two-output patient model. Because of the difference in patient’s sensitivity to the drug, and in order to cover the wide ranges of patients, Model Reference Adaptive Control (MRAC) has been implemented to obtain the optimal infusion rates of DPM and SNP. This is developed in chapters five and six. Computer simulations were carried out to investigate the performance of this controller. The results show that the proposed adaptive scheme is robust with respect to disturbances and variations in model parameters, the simulation results have demonstrated that this algorithm cannot cover the wide range of patient’s sensitivity to drugs, due to that shortcoming, a PID controller using a Neural Network that tunes the controller parameters was designed and implemented. The parameters of the PID controller were optimised offline using Matlab genetic algorithm. The proposed Neuro-PID controller has been tested and validated to demonstrate its merits and capabilities compared to the existing approaches to cover wide range of patients.

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Braga, Mateus Freitas. "Projeto e simulação de um filtro híbrido monofásico para correção do fator de potência e compensação harmônica em uma rede industrial." Universidade Federal de Juiz de Fora (UFJF), 2017. https://repositorio.ufjf.br/jspui/handle/ufjf/5361.

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Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-07-03T11:17:42Z No. of bitstreams: 1 mateusfreitasbraga.pdf: 1732565 bytes, checksum: f8ebb1cc4fe4d9ecbd9cc50ba3eb3f2a (MD5) Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T21:17:21Z (GMT) No. of bitstreams: 1 mateusfreitasbraga.pdf: 1732565 bytes, checksum: f8ebb1cc4fe4d9ecbd9cc50ba3eb3f2a (MD5) Made available in DSpace on 2017-08-07T21:17:21Z (GMT). No. of bitstreams: 1 mateusfreitasbraga.pdf: 1732565 bytes, checksum: f8ebb1cc4fe4d9ecbd9cc50ba3eb3f2a (MD5) Previous issue date: 2017-03-20 Cresce a cada dia o n úmero de cargas não lineares conectadas aos diversos sistemas el étricos, seja em ní vel de transmissão ou distribui ção. Como consequência desse crescimento, e possí vel encontrar casos de consumidores enfrentando problemas relacionados a desarmes de disjuntores e sobreaquecimento de condutores, entre outros efeitos indesejados. Tomando um desses casos como base para este estudo, esta disserta ção tem o objetivo de avaliar e propor uma solu ção para uma rede monof asica real, que possivelmente e comum a outros consumidores. A carga monof ásica composta por lumin árias a LED (t picas cargas não lineares) e cargas indutivas se apresenta aos terminais da fonte com um comportamento de elevado conte udo harmônico (THD) de corrente e baixo fator de potência. Essa condi ção adversa pode ser mitigada de diversas maneiras, como por exemplo pela a ção de um fi ltro passivo,fi ltro ativo ou ainda fi ltro h brido (o qual e composto por uma combina ção dos dois primeiros). Ser a proposto nesta disserta ção uma metodologia de projeto relacionada a aplica ção de um fi ltro hi brido monof ásico visando corrigir o fator de potência e reduzir o conte udo harmônico de corrente presente na fonte, tomando como base as caracterí sticas do sistema avaliado em uma ind ústria gr áfi ca t ípica. Serão investigadas algumas con gura ções de filtros com o objetivo de mitigar problemas de Qualidade de Energia El étrica. Como consequência, ser a desenvolvida a an álise matem atica da topologia adotada e o projeto do controlador, baseado em um controlador proporcional-ressonante e na Teoria p-q Monof asica. A veri ca ção da solu ção proposta e sustentada pelos resultados de simula ção obtidos via software PSIM. The amount of non-linear loads connected to the various electrical systems grows on a daily basis, regardless those loads are tied to a transmission or distribution bar. As a consequence of this growth, it is possible to nd cases of consumers facing problems such as tripping of breakers and cables overheating, among other undesired e ects. Taking one of these cases as the focus of this study, this dissertation aims to evaluate and propose a solution to a real single-phase system, which could be considered similar to other consumers. The single-phase load composed of LED luminaires (typical non-linear load) and inductive loads presents high THD and low power factor behavior at source terminals. This condition can be mitigated by using some well-known techniques, such as passive lters, active lters or hybrid lters, (which are composed by the combination of the former two). This Master document Thesis proposes a design methodology of a single-phase hybrid lter aiming power factor correction and reduction of the harmonic content of the current delivered by the AC power supply when feeding a typical printing factory. It will be reviewed and discussed some possible lter con gurations aimed to solve the case under evaluation. It is also included the mathematical analysis of the proposed topology, along with the design of the control system of the inverter. The Single-Phase p-q Theory is reviewed in order to design the control. The closed-loop control is desinged by a proportional-resonant compensator. Simulation results, by employing the PSIM software, are provided aiming to validate the solution proposed.

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Chaves, Eric Nery. "Otimização meta heurística e controle baseado no modelo interno aplicados em sistemas de geração fotovoltaica conectados à rede elétrica monofásica." Universidade Federal de Uberlândia, 2016. https://repositorio.ufu.br/handle/123456789/17965.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Este trabalho apresenta o estudo, desenvolvimento e aplicação de novas técnicas de controle aos sistemas de geração de energia fotovoltaica, conectados à rede elétrica monofásica, visando a melhoria da eficiência destes sistemas em relação aos métodos de controle tipicamente utilizados. O trabalho é dividido em duas partes principais, as quais estão relacionadas ao rastreamento do ponto de máxima potência (Maximum Power Point Tracking – MPPT) e, depois, ao controlador interno dos conversores boost-quadrático – lado dos painéis fotovoltaicos – assim como aos controladores do inversor de tensão, no lado da rede elétrica monofásica. A primeira parte do trabalho consiste no desenvolvimento de um algoritmo de meta heurística para o MPPT, o qual é baseado no método do recozimento simulado (Simulated Annealing - SA) e tem como objetivo a determinação do ponto de máximo global, buscando soluções fora de uma vizinhança próxima, de modo a evitar o atracamento em máximos locais da curva de potência de saída do arranjo de painéis fotovoltaicos, melhorando, assim, o aproveitamento da energia em situações de sombreamento parcial. A segunda parte do trabalho apresenta o projeto de controladores baseados no modelo interno (Internal Model Control – IMC) com 1 grau de liberdade (1 Degree of Freedom – 1 DOF) aplicados, primeiramente, ao conversor CC-CC Boost Quadrático, utilizado para o MPPT, e, posteriormente, a um inversor de tensão com filtro LCL, conectado à rede elétrica monofásica, operando no modo de injeção de corrente. É apresentada a modelagem matemática de ambos os conversores e analisada a compensação da realimentação interna ao sistema do inversor de tensão, correspondente ao desacoplamento da tensão da rede, através da estratégia de alimentação à frente (Feedforward). Visando-se uma base de comparação, para a análise de desempenho do conversor IMC – 1DOF, também é aplicado ao sistema de injeção de corrente, o controlador Proporcional-Ressonante (P+Res). São apresentados resultados de simulação computacional e experimentais de ambos os 8 controladores, os quais permitem verificar o desempenho do sistema em situação de rede fraca e carga local não-linear. This paper presents the study, development and application of new control techniques for photovoltaic power generation systems, connected to single-phase power grid in order to improve the efficiency of these systems in relation to control methods typically used. The work is divided into two main parts, which are related to tracking the maximum power point (Maximum Power Point Tracking - MPPT) and then the internal controller of boost quadratic converters - side of the photovoltaic panels - as well as the controllers the voltage inverter, the side of the single-phase mains. The first part of the work is the development of a heuristic goal algorithm for MPPT, which is based on the method of simulated annealing (Simulated Annealing - SA) and aims at determining the overall maximum point, seeking out solutions in a close vicinity, so as to prevent the docking local maxima in the curve of power output of the photovoltaic array, thereby improving the utilization of energy in partial shading situations. The second part presents the design of controllers based on internal model (Internal Model Control - IMC) with 1 degree of freedom (1 Degree of Freedom - 1 DOF) applied, first, the DC-DC Boost Quadratic converter, used for MPPT, and thereafter, a voltage inverter with LCL filter connected to the single phase power supply operating in current injection mode. A mathematical modeling of both converters and analyzed the compensation of internal feedback to the voltage inverter system corresponding to the disconnection of the mains voltage through the power strategy a head (feedforward). A basis of comparison for the performance analysis of IMC-1DOF converter is aiming at, is also applied to the current injection system, Proportional-Resonant Controller (P + Res). They are presented computer simulation and experimental results of both controllers, which allow you to check the system performance in low and non-linear local load network situation. Tese (Doutorado)

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Benigno, Tayara Crystina Pereira. "Modelagem matemática e controle de atitude e posição do quadrotor." Universidade Federal Rural do Semi-Árido, 2015. http://bdtd.ufersa.edu.br:80/tede/handle/tede/538.

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Made available in DSpace on 2016-08-31T13:33:46Z (GMT). No. of bitstreams: 1 TayaraCPB_Dissert.pdf: 1984521 bytes, checksum: 5a46c1781124a49b404a083b87b969bd (MD5) Previous issue date: 2015-08-28 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior With advances in technology and the popularization of the use of Unmanned Aerial Vehicles (UAV's) so does the need to use more robust and more effective control techniques. Among the various types of unmanned aerial vehicles, this paper will focus on quadrotor model, which has a mechanical structure in the form of x, whose ends have an engine and propeller assembly, where the rotation of this group is responsible for the lift and the movements developed by quadrotor. This feeling, aiming to apply drivers that provide stability to the dynamic system. This study aims to conduct mathematical modeling using the Euler-Lagrange. With this, it is proposed a PID controller (Proportional Integral Derivative) to maintain stable the three orientation angles and height to a desired value. The development of the proposed controller will be validated via simulation confirming the application feasibility of the technique presented stability Com o avanço tecnológico e a popularização do uso dos Veículos Aéreos Não Tripulados (VANT s) cresce também a necessidade do uso de técnicas de controle mais robustas e mais eficazes. Dentre os mais diversos tipos de veículos aéreos não tripulados, este trabalho irá focar no modelo do quadrotor, que possui uma estrutura mecânica em forma de cruz, cujas extremidades têm um conjunto de motor e hélice, onde a rotação desse conjunto é responsável pela força de sustentação e pelos movimentos desenvolvidos pelo mesmo. Objetivando aplicar controladores que proporcione estabilidade ao sistema dinâmico deste veiculo aéreo. O presente trabalho tem como objetivo realizar a modelagem matemática deste sistema usando as equações de Euler-Lagrange. Tendo isso, é proposto um controlador PID (Proporcional Integral Derivativo) para manter os três ângulos de orientação estáveis e a altura em um valor desejado. O desenvolvimento do controlador proposto será validado via simulação confirmando a viabilidade da aplicação da técnica de estabilidade apresentada

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Jebelli, Ali. "Development of Sensors and Microcontrollers for Underwater Robots." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31283.

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Nowadays, small autonomous underwater robots are strongly preferred for remote exploration of unknown and unstructured environments. Such robots allow the exploration and monitoring of underwater environments where a long term underwater presence is required to cover a large area. Furthermore, reducing the robot size, embedding electrical board inside and reducing cost are some of the challenges designers of autonomous underwater robots are facing. As a key device for reliable operation-decision process of autonomous underwater robots, a relatively fast and cost effective controller based on Fuzzy logic and proportional-integral-derivative method is proposed in this thesis. It efficiently models nonlinear system behaviors largely present in robot operation and for which mathematical models are difficult to obtain. To evaluate its response, the fault finding test approach was applied and the response of each task of the robot depicted under different operating conditions. The robot performance while combining all control programs and including sensors was also investigated while the number of program codes and inputs were increased.

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Cordero, Bautista Luis Gustavo. "Aplicação do algoritmo genético adaptativo com hipermutação no ajuste dos parâmetros dos controladores suplementares e dispositivo FACTS IPFC /." Ilha Solteira, 2019. http://hdl.handle.net/11449/182292.

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Orientador: Percival Bueno de Araujo Resumo: As perturbações ou variações de carga produzem oscilações eletromecânicas que devem ser amortecidas o mais rápido possível para garantir confiabilidade e estabilidade da rede. Neste trabalho apresenta-se uma análise do dispositivo FACTS Interline Power Flow Controller (IPFC) e o controlador Proporcional Integral (PI) no gerenciamento dos fluxos de potência e a influência dos Estabilizadores do Sistema de Potência (ESP) e do IPFC Power Oscillation Damping (POD) sobre a estabilidade do sistema elétrico de potência. Neste trabalho enfoca-se nos estudos de estabilidade a pequenas perturbações usando um Algoritmo Genético Adaptativo com Hiper-mutação (AGAH) para ajustar os parâmetros dos controladores suplementares de amortecimento, o Estabilizador de sistema de potência (ESPs) e o Power Oscillation Damping (POD) em forma coordenada. O AGAH tem como objetivo encontrar os parâmetros ótimos do controlador para melhorar o amortecimento fraco das oscilações de baixa frequência locais e inter-área. Neste trabalho representa-se o sistema de elétrico de potência com a inclusão do dispositivo Interline Power Flow Controller com o modelo de sensibilidade de corrente (MSC). Considera-se como sistema teste o sistema Simétrico de Duas Áreas e o sistema New England como o intuito de avaliar o algoritmo proposto. As simulações são feitas no ambiente do MatLab. Por fim, apresenta-se a comparação do algoritmo genético com o desempenho do algoritmo proposto. Abstract: Small-magnitude disturbances happen to produce electro-mechanical oscillations which should be damped as quickly as possible to ensure reliability and stability of the network. This work presents an analysis of Interline Power Flow Controller (IPFC) FACTS device and PI controller to control and manage power flow and also how Power System Stabilizers and IPFC Power Oscillations Damping (POD) controller influence over an electric power system stability. This work focuses on small-signal stability studies using an Adaptive Genetic Algorithm with Hyper-mutation (AGAH) in order to tune controller parameters in a coordinated way ensuring proper damping. AGAH aims to find optimal controller parameters to enhance the poor damping of local and inter-area low frequency oscillations. This works represents the electric power system and Interline Power Flow Controller device by a current sensitivity model (CSM). This paper considers two areas 14 bus symmetrical power system and New England power system in order to assess proposed algorithm. Coding and Simulations take place in MatLab platform. AGAH and GA get compared by time convergence and performance. This paper shows AGAH is an interesting optimization technique which outweighs GA. Mestre

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Sola, Yoann. "Contributions to the development of deep reinforcement learning-based controllers for AUV." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2021. http://www.theses.fr/2021ENTA0015.

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L’environnement marin est un cadre très hostile pour la robotique. Il est fortement non-structuré, très incertain et inclut beaucoup de perturbations externes qui ne peuvent pas être facilement prédites ou modélisées. Dans ce travail, nous allons essayer de contrôler un véhicule sous-marin autonome (AUV) afin d’effectuer une tâche de suivi de points de cheminement, en utilisant un contrôleur basé sur de l’apprentissage automatique. L’apprentissage automatique a permis de faire des progrès impressionnants dans de nombreux domaines différents ces dernières années, et le sous-domaine de l’apprentissage profond par renforcement a réussi à concevoir plusieurs algorithmes très adaptés au contrôle continu de systèmes dynamiques. Nous avons choisi d’implémenter l’algorithme du Soft Actor-Critic (SAC), un algorithme d’apprentissage profond par renforcement régularisé en entropie permettant de simultanément remplir une tâche d’apprentissage et d’encourager l’exploration de l’environnement. Nous avons comparé un contrôleur basé sur le SAC avec un contrôleur Proportionnel-Intégral-Dérivé (PID) sur une tâche de suivi de points de cheminement et en utilisant des métriques de performance spécifiques. Tous ces tests ont été effectués en simulation grâce à l’utilisation de l’UUV Simulator. Nous avons décidé d’appliquer ces deux contrôleurs au RexROV 2, un véhicule sous-marin téléguidé (ROV) de forme cubique et à six degrés de liberté converti en AUV. Grâce à ces tests, nous avons réussi à proposer plusieurs contributions intéressantes telles que permettre au SAC d’accomplir un contrôle de l’AUV de bout en bout, surpasser le contrôleur PID en terme d’économie d’énergie, et réduire la quantité d’informations dont l’algorithme du SAC a besoin. De plus nous proposons une méthodologie pour l’entraînement d’algorithmes d’apprentissage profond par renforcement sur des tâches de contrôle, ainsi qu’une discussion sur l’absence d’algorithmes de guidage pour notre contrôleur d’AUV de bout en bout The marine environment is a very hostile setting for robotics. It is strongly unstructured, very uncertain and includes a lot of external disturbances which cannot be easily predicted or modelled. In this work, we will try to control an autonomous underwater vehicle (AUV) in order to perform a waypoint tracking task, using a machine learning-based controller. Machine learning allowed to make impressive progress in a lot of different domain in the recent years, and the subfield of deep reinforcement learning managed to design several algorithms very suitable for the continuous control of dynamical systems. We chose to implement the Soft Actor-Critic (SAC) algorithm, an entropy-regularized deep reinforcement learning algorithm allowing to fulfill a learning task and to encourage the exploration of the environment simultaneously. We compared a SAC-based controller with a Proportional-Integral-Derivative (PID) controller on a waypoint tracking task and using specific performance metrics. All the tests were performed in simulation thanks to the use of the UUV Simulator. We decided to apply these two controllers to the RexROV 2, a six degrees of freedom cube-shaped remotely operated underwater vehicle (ROV) converted in an AUV. Thanks to these tests, we managed to propose several interesting contributions such as making the SAC achieve an end-to-end control of the AUV, outperforming the PID controller in terms of energy saving, and reducing the amount of information needed by the SAC algorithm. Moreover we propose a methodology for the training of deep reinforcement learning algorithms on control tasks, as well as a discussion about the absence of guidance algorithms for our end-to-end AUV controller

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Dam, Shimul Kumar. "Power Electronic Converters for Condition Monitoring and Voltage Equalization of Batteries." Thesis, 2019. https://etd.iisc.ac.in/handle/2005/4534.

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Power converters are used in battery-based storage systems in many applications. Apart from the task of regulating the charging and discharging, the power electronic converters can also help to monitor battery condition and to avoid over-charge or over-discharge of any battery cell. One approach to monitoring the cell condition is by measuring its impedance. The power converter for charging and discharging of the cell stack can be used for online measurement of cell impedances. The challenges involved in control, measurement, and the hardware requirements for impedance measurement are analyzed in this work, and suitable solutions are proposed. A Proportional Integral Resonant (PIR) controller-based control scheme and a DAC based measurement method are proposed for impedance measurement over the required frequency range. Two di erent approaches are proposed to achieve su cient output voltage resolution for generating small amplitude voltage perturbation. One approach achieves high voltage resolution by replacing the single-leg buck converter with a multi-leg interleaved converter. The other approach uses a low-power rated auxiliary converter in series with the main converter to achieve high voltage resolution. Both of the methods are experimentally veri ed and compared with commercial equipment and the advantages of each approach are evaluated. A voltage equalizer is a power electronic circuit that equalizes the cell voltages in a series- connected cell stack to avoid over-charge and over-discharge of any individual cell. A low- cost voltage equalizer using selection switches for a cell to cell equalization is proposed. This equalizer uses capacitive voltage level shifting to avoid bulky and lossy isolation transformer and to reduce cost. A new approach with a lower number of low-frequency selection switches further reduces the equalizer cost. A high-performance voltage equalizer is also proposed to achieve fast equalization by direct multi-cell to multi-cell charge transfer. This topology is shown to provide soft-switching with high e ciency. The equalizer is controlled in an open loop. The equalization currents do not reduce with progress in voltage equalization, making this topology faster than the existing open-loop multi-cell to multi-cell topologies. A modularization method is proposed for this topology to provide a direct path for charge transfer from any cell in one module to any cell in another module. The operation of both the equalizers and the modularization technique are experimentally veri ed which con rms the theoretical analysis.

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Lee, Ping-Hui, and 李炳輝. "Using Grey Proportional Integral Controller forPrecision Time Synchronization Protocol." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/17532358044805043883.

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碩士 國立臺灣大學 電機工程學研究所 96 IEEE1588 standard is a precision time synchronization protocol (PTP). It is designed to synchronize real-time clocks in the nodes of a distributed system that communicate using a network. Within a subnet, the PTP system is expected to achieve the synchronization accuracy in sub-microsecond range. Thus, it is applicable to traditional measurement and control systems, industrial automation systems, communication systems, electrical power systems and many other areas of modern technology.The unit of clock servo plays important roles in the PTP system. It is usually implemented by proportional integral (PI) controller. The time offsets between the master and the slave clock are fed into the PI controller. The output of the PI controller is used to steer the slave clock to synchronize with the master clock. Therefore, the relative tick-rate of the slave clock can be stabilized. In order to improve the performance of the PI controller, this study adopts the gray theory to determine the parameter of the proportional term of the PI controller. The drift of the time offset from master clock can be obtained by using the gray prediction algorithm. Accordingly, the gray PI controller makes the system reduce the time to reach steady state. To assess the performance of the system, this study integrates the PTP software and the network interface with timestamper to establish a subnet. For the stability analysis of the system under tests, this paper utilizes the ITU-T recommended Allan deviation. Experimental results show that the performance of the gray PI controller is better than the traditional one. The transient response time of the system is significantly reduced by introducing the proposed gray PI controller.

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Li, Huang-Yi, and 李皇儀. "Applied Particle Swarm Optimization Algorithms to Parameters Tuning of Digital Proportional - Integral Controller." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/30502467646046001582.

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碩士 龍華科技大學 工程技術研究所 99 PID controller can be divided into traditional PID and digital PID. The latter is consisted in the time series form. In this paper, applied Particle Swarm Optimization algorithm to parameters tuning of the digital PI controller, and compared with the Weighting Ziegler – Nichols (Z-N) algorithm. Particle Swarm Optimization algorithm uses a continuous iterative method to optimize, as genetic algorithm. Particle Swarm Optimization only processes the optimal solution and refreshing formula. It is easier than those steps of genetic algorithm. So, in the reasonable searching range, the speed of searching optimal solution of Particle Swarm Optimization algorithm is more quick than that of genetic algorithm. The paper uses permanent magnet synchronous motor as a controlled plant. The simulation program uses Matlab software. Simulation results confirm that the Particle Swarm Optimization applied to parameters tuning of the digital PI controller is better than weighted Z-N PI controller.

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Liao, Kuo-Yuan, and 廖國淵. "Design of a Single-Phase Inverter using Trapezoidal Integration-Based Proportional Integral Derivative Controller." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/2vsau7.

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碩士 義守大學 電機工程學系 103 Traditional PID (proportional-integral-derivative) controllers have been broadly applied to single-phase inverters due to their simple structures and easy designs. Yet, the integral term of traditional PID controllers is based on rectangular integration. If the load of the inverter is highly non-linear, the precision of calculations will be low, and there will be steady-state errors. This thesis proposed a PID controller based on trapezoidal integration. Unlike rectangular integration, trapezoidal integration does not underestimate the error area, which can further result in calculation errors. Thus, the proposed single-phase inverter can achieve low total harmonic distortion (THD) output voltage and fast dynamic response. The problem with inverters using traditional PID controller of possible tracking errors in cases with highly non-linear loads can be resolved. To verify the effectiveness of the proposed controller, this thesis used the software MATLAB to run simulations. And the results showed that the AC output voltage of the proposed single-phase inverter is of high quality in any case with resistive load, step load change, or non-linear load.

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Chen, Chih-Hao, and 陳志豪. "Dynamically Adjusted Proportional-Integral Technology in Servo Speed Mode for Roll-to-Roll Controller." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/72102580678738095726.

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碩士 逢甲大學 資訊電機工程碩士在職專班 104 In this study, the application of the R2R (roll to roll) tension control of the speed, capability and stability is proposed. The system is based on proportional - integral compensation control the servo motor speed to obtainfixed speed and tension. In the control system architecture, consists of unwinding system, fixed speed system, and winding system. Systems begin with plastic bag lamination off axis tension, each independent tension detection device can individually feedback. In addition to fixed speed systems, winding and rewinding system because there are roll diameter changes, so roll diameter calculation can be applied to obtain the line speed. Tension detection and feedback units use a proportional - integral servo motor speed adjustment of the system to get a high stability of tension and speed control. Traditional control method is via the AD / DA module feedback tension value changes with severally servo motor torque control mode to reach a certain tension. This study proposed proportional - integral pre-integrated system to compensate servo motor speed and precise diameter calculation to obtain higher and more precise control accuracy and stability.

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Jheng, Hao-Yi, and 鄭浩逸. "An Adaptive Proportional-Integral Controller for Power Management of 3D Graphics System-On-Chip." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/aw3jbr.

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碩士 國立中山大學 資訊工程學系研究所 97 In the past few years, due to the rapid advance in technology and the aid of 3D graphics applications the world of 3D graphics is rapidly expanding from desktop computers and dedicated gaming consoled to handheld devices, such as cellular phones, PDAs, laptops etc.,. However, unlike traditional desktop computers and gaming consoles, mobile computing devices typically have slower processors that have less capability for handling large computation-intensive workloads like 3D graphics application. In addition, the power consumption is one of the major design specifications to realize the 3D graphics accelerating engine for mobile devices because handheld batteries have limited lifetimes. Moreover, the size of chip is depend on the Moore’s Law: The number of transistors in a chip are double in every eighteen months. Even though the produce cost is decrease, but the capacity of battery cannot increase like the transistors. Therefore, how to reduce power consumption by using efficient power management techniques has become a very important research topic in 3D graphics SoC design. For 3D graphics applications, dynamic voltage and frequency scaling (DVFS) is a good candidate to reduce the power consumption of 3D graphics accelerating engine. So many relative papers have researched in how to accurately predict the workload and scale the voltage and frequency. The prediction policy can divide into History-based predictor [1] and Frame-structure predictor [2-4]. The History-based predictor predicts the latter frame workload by previous frame workload to scale the voltage, and the frame-structure predictor performs offline and then determine the different kind of frame for an application. A table is used to save the mapping of different kind of frame to the voltage, and then the voltage is scaled according to the mapping table. A lot of researchers put the power management policy in software i.e. processors, but our proposed workload prediction scheme has been realized into the hardware circuit. Therefore, it can not only reduce the overhead of processor but also quickly adjust the voltage and frequency of 3D graphics accelerating engine. Our prediction policy is one of the History-based predictor ,and it is an adaptive PID predictor [5-6] in which the parameters of Proportional controller and Integral controller can be adaptively adjusted so that it can obtain more accurate prediction results than non-adaptive predictor. In general, the workload that the selected voltage can handle is usually over than the predicted workload. That is, actual workload is usually less than predicted workload. So that the slack time will be generated. We can utilize the slack time through Inter-frame compensation [7-10] to save more energy while maintaining the similar output quality. We use a simple policy to adaptively select the parameters for compensation between the frames to simplify the hardware architecture of the power management policy. Experimental results show that, we can get more energy saving and more accurate workload prediction when the adaptive PI predictor and adaptive Inter-frame compensation are utilized.

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Chuang, Chih-Hsien, and 莊志賢. "Design of Proportional Integral Derivative Controller with Feedforward Control and Dead Zone for PWM Inverters." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/s59srs.

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碩士 義守大學 電機工程學系 103 Traditional proportional-integral-derivative (PID) controllers have been broadly applied to pulse-width modulation (PWM) inverters due to their simple structures and easy designs. However, traditional PID controllers are sensitive to parameter changes and load interferences. This fact may result in high total harmonic distortion (THD) and slow dynamic response in cases with an inverter of highly non-linear load. Thus, this thesis proposes a (PID) controllers with feedforward control and dead zone. With the dead zone PID controller, the sensitivity to large parameter changes and highly non-linear load can be reduced. And the feedforward control can enhance dynamic response, that in cases with an inverter of highly non-linear load, there can be low THD and fast dynamic response. To verify the effectiveness of the proposed controller, this thesis used the software MATLAB to run simulations. And the results showed that the proposed inverter can achieve low THD and fast dynamic response in cases with non-linear load.

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Nkwanyana, Thamsanqa Bongani. "Multi-input multi-output proportional integral derivative controller tuning based on improved particle swarm optimization." Diss., 2021. http://hdl.handle.net/10500/27692.

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The PID controller is regarded as a dependable and reliable controller for process industry systems. Many researchers have devoted time and attention to PID controller tuning and they all agree that PID controllers are very important for control systems. A PID equation is very sensitive; its parameters must always be varied following the specific application to increase performance, such as by increasing the system’s responsiveness. PID controllers still have many problems despite their importance for control systems in industries. The problem of big overshoot on the conventional gain tuning is one of the serious problems. Researchers use the PSO algorithm to try and overcome those problems. The tuning of the MIMO PID controller based on the PSO algorithm shows many disadvantages such as high-quality control with a short settle time, steady-state error, and periodical step response. The traditional PSO algorithm is very sensitive and it sometimes affects the quality of good PID controller tuning. This research has proposed a new equation for improving the PSO algorithm. The proposed algorithm is the combination of linearly decreasing inertia weight and chaotic inertia weight, after which a control factor was introduced as an exponential factor. This was very useful for simulations as it is adjustable. The Matlab simulation results of the experiments show that the simulations as it is adjustable. The Matlab simulation results of the experiments show that the new proposed equation converges faster and it gives the best fitness compared to linear inertia weight and oscillating inertia weight and other old equations. The MIMO PID controller system that consists of four plants was tuned based on the new proposed equation for the PSO algorithm (LCPSO). The optimized results show the best rise time, settling time, time delays, and steady-state compared to the systems that are tuned using the old equations. The exploration was directed at considering the impact of using the PSO calculation as an instrument for MIMO PID tuning. The results obtained in the examination reveal that the PSO tuning output improved reactions and can be applied to various system models in the measure control industry. The results for the MIMO PID controller tuned using PSO were assessed using integral square error (ISE), integral absolute error (IAE), and the integral of time expanded by absolute error (ITAE). The five well-known benchmark functions were also used to endorse the feasibility of the improved PSO and excellent results in terms of convergence and best fitness were attained. Electrical and Mining Engineering M. Tech. (Electrical Engineering)

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徐德君. "Fuzzy Proportional-Integral Control on Automatic Gain Controller Design for the Wireless Local Area Networks." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/30337529838349966052.

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碩士 國立中興大學 電機工程學系 91 This thesis aims at the automatic gain controller (AGC) design for a IEEE 802.11b baseband processor receiver. We propose Fuzzy PI control strategy to regulate the amplitude of the input signal to the baseband A/D converter. The operational delay and the system convergence are analyzed through a software package Synopsys and FPGA emulators Altera FLEX10K50E. Robustness and fault tolerance are verified through experimental results.

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Zhan, Xun Xain, and 詹勳賢. "A Hybrid Particle Swarm Optimization / Proportional Integral controller for the Low Earth Orbit Satellite Tracking System." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36628114084058869344.

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碩士 國立高雄應用科技大學 電子工程系碩士班 101 The purpose of this thesis is to develop an intelligent algorithm of control system to track low-orbit satellites. Satellite tracking methods rely on SGP4 orbit forecasting model generated by the antenna pointing database and follow the point coordinates to command the rotation of the axes. Gears rotation gap will affect the strength of the received signal. The PI controller can adjust the error values caused by the drive shaft mechanism. Particle swarm optimization has fewer parameter settings and the advantages of fast convergence used for parameter optimization and variable selection. And particle swarm optimization algorithm can be used to search for the PI controller parameters, k_p and k_i. In the search process using resolver feedback mechanism of actual angle indicator as a basis to judge the fitness value of pros and cons. The experimental results demonstrate the reliability of proposed system and the function of program track mode.

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Lin, Yenku, and 林彥谷. "Design and Implementation of Modified Proportional Integral Derivative Controller with Differential Forward for DC-AC Inverters." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/56116073130236878859.

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碩士 義守大學 電機工程學系 101 Due to simple structure and good dynamic property, Differential forward PID (DFPID) controller is widely used in DC-AC inverters control. However, the conventional DFPID controller is difficult to inhibit the disturbance of output signal, thus causing the deterioration of the inverter performance. In order to inhibit the disturbance of output signal and enhance the system robustness, a modified differential forward PID (MDFPID) controller for the DC-AC inverter design is proposed in this thesis. The performances of the DC-AC output are low total harmonic distortion, and fast dynamic response under linear and non-linear loading. In addition to retaining the advantages of simple structure and good dynamic property as the conventional DFPID controller, the MDFPID controller has also allowed easy adjustment of control parameters and significant inhibition of disturbance of output signal. To verify the effectiveness of this proposed controller, the Psim software is used to simulate the inverter and the experiment is also realized with digital signal processor. Finally, a high-quality AC output voltage can be obtained under non-linear loading.

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33

Chang, Chin-Ping, and 張進評. "DESIGN OF A HYBRID FUZZY LOGIC PROPORTIONAL PLUS INTEGRAL-DERIVATIVE CONTROLLER FOR A CLASS OF NONLINEAR SYSTEMS." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/02072317454608048046.

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碩士 大同大學 電機工程學系(所) 93 In this thesis, we used PID-type controller as the foundation, to develop a hybrid fuzzy logic proportional term plus conventional integral and derivative terms (FUZZY P+ID) controller for improving the control response. This kind of controller is constructed by using an incremental fuzzy logic controller in place of the proportional term in the conventional PID controller. This thesis basic principle of this study is to reduce the parameters of a fuzzy controller to be tuned so that, in comparison with the PID-type controller, only one additional parameter should be adjusted. Using conventional PID controller, however, it is difficult to achieve a desired tracking control performance since the dynamic equations of a plant for the manipulator are tightly coupled, highly nonlinear and uncertain. In order to improve the tracking control performance under uncertainty, we propose a new hybrid control scheme for the nonlinear plants, which consists of a fuzzy logic proportional controller and a conventional integral and derivative controller (FUZZY P+ID). Finally, detailed numerical design processes and simulation results are performed to illustrate the effectiveness of the proposed scheme.

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Wang, Hung-Kai, and 王宏鍇. "A Dynamic Adjusted Proportional-Integral Controller for Semiconductor Manufacturing and an Empirical Study of Critical Dimension and Overlay Errors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/64556414674496491360.

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碩士 國立清華大學 工業工程與工程管理學系 98 Semiconductor industry and its products change fast with time. There are about 300 to 500 processes in semiconductor manufacturing, and there are many factors affecting each process. Therefore, it is hard to estimate the input-output model for one process, and also hard to estimate the process disturbance distribution or model. However, in most of fabs in semiconductor industry, they use EWMA controller to control the process, which cannot adjust the control parameter with process disturbance. This research considers the situation that it is hard to estimate the process disturbance model, and propose a framework for the Dynamic Adjusted Proportional-Integral (DAPI) controller. By adjusting the control parameters lot by lot, we can effectively solve the problems mentioned above. And we will illustrate an empirical study of critical dimension control and overlay errors reduction of photolithography, both consider the time series disturbance model and real process disturbance. We will compare the output result with traditional EWMA (Exponentially Weighted Moving Average) controller, and show that DAPI controller can make the process closer to target and reduce the process output variance than EWMA controller. In addition, in real semiconductor manufacturing situation, there exists process sudden Shift and metrology Delay problems, which make the controller performs worse. Since DAPI controller adjusts input value slowly, it will not be affect by process sudden Shift. We will show that DAPI controller can solve those problems, and can be used to a real semiconductor manufacturing situation. Finally, in the real process disturbance situation, for critical dimension control, DAPI can improve 10% on Process Capability Ratio and improve 11% on process standard deviation. Also, for overlay errors reduction, DAPI can improve 16% on Range and improve 11% on root Mean squared error. For all scenarios and two real problems, DAPI can perform better than EWMA controller.

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35

Mendes, Carlos Hugo Ribeiro. "Robust Controller Design for an Autonomous Underwater Vehicle." Master's thesis, 2017. http://hdl.handle.net/10400.6/7956.

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Worldwide there has been a surge of interest in Autonomous Underwater Vehicles (AUV). The ability to operate without human intervention is what makes this technology so appealing. On the other hand, the absence of the human narrows the AUV operation to its control system, computing, and sensing capabilities. Therefore, devising a robust control is mandatory to allow the feasibility of the AUV. Motivated by this fact, this thesis aims to present, discuss and evaluate two linear control solutions being proposed for an AUV developed by a consortium led by CEiiA. To allow the controller design, the dynamic model of this vehicle and respective considerations are firstly addressed. Since the purpose is to enable the vehicle’s operation, devising suitable guidance laws becomes essential. A simple waypoint following and station keeping algorithm, and a path following algorithms are presented. To devise the controllers, a linear version of the dynamic model is derived considering a single operational point. Then, through the decoupling of the linear system into three lightly interactive subsystems, four Proportional Integral Derivative controllers (PIDs) are devised for each Degree Of Freedom (DOF) of the vehicle. A Linear Quadratic Regulator (LQR) design, based on the decoupling of the linear model into longitudinal and lateral subsystems is also devised. To allocate the controller output throughout the actuators, a control allocation law is devised, which improves maneuverability of the vehicle. The results present a solid performance for both control methods, however, in this work, LQR proved to be slightly faster than PID. É visível, a nível mundial, um aumento considerável do interesse em Veículos Autónomos Subaquáticos (Autonomous Underwater Vehicles - AUV). O que torna esta tecnologia tão atraente é a capacidade de operar sem intervenção humana. Contudo, a ausência do ser humano restringe a operação do AUV ao seu sistema de controlo, computação e capacidades de detecção. Desta forma, conceber um controlo robusto é obrigatório para viabilizar o AUV. Motivado por este facto, esta tese tem como objetivo apresentar, discutir e avaliar duas soluções de controlo linear, a propor a um AUV desenvolvido por um consórcio liderado pelo CEiiA. Para que o projeto do controlador seja possível, o modelo dinâmico deste veículo e respectivas considerações são primeiramente abordados. Com a finalidade de possibilitar a operação do veículo, torna-se essencial a elaboração de leis de guidance adequadas. Para este efeito são apresentados algorítmos de Waypoint following e Station keeping, e de path following. Para a projeção dos controladores é derivada uma versão linear do modelo dinâmico, considerando um único ponto operacional. Através da separação do modelo linear em três subsistemas são criados quatro controladores Proporcional Integral Derivativo (PID) para cada grau de liberdade (Degree Of Freedom - DOF) do veículo. É também projetado um Regulador Linear Quadrático (LQR), baseado na separação do modelo linear em dois subsistemas, longitudinal e lateral. É ainda apresentada uma lei de alocação de controlo para distribuir o sinal de saída dos controladores pelos diferentes atuadores. Esta provou melhorar a manobrabilidade do veículo. Os resultados finais apresentam um desempenho sólido para ambos os métodos de controlo. No entanto, neste trabalho, o LQR provou ser mais rápido do que o PID.

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36

Ghoshal, Anirban. "Operation of Three Phase Four Wire Grid Connected VSI Under Non-Ideal Conditions." Thesis, 2013. http://etd.iisc.ernet.in/2005/3386.

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The necessity to incorporate renewable energy systems into existing electric power grid and need of efficient utilization of electrical energy are growing every day. A shunt connected Voltage Source Inverter(VSI) capable of bidirectional power flow and fast control has become one of the building block to address such requirements. However with growing number of grid connected VSI, new requirements related to harmonic injection, higher overall efficiency and better performances during short term grid disturbances have emerged as challenges. For this purpose a grid connected three phase four wire VSI with LCL filter can be considered as a general module to study different control approaches and system behavior under ideal and non-ideal grid conditions. This work focuses on achieving enhanced performance by analyzing effect of non-ideal conditions on system level and relating it to individual control blocks. In this work a phase locked loop structure has been proposed which is capable of extracting positive sequence fundamental phase information under non-ideal grid conditions. It can also be used in a single phase system without any structural modification. The current control for the three phase four wire VSI system has been implemented using Proportional Resonant (PR) controller in a per phase basis in stationary reference frame. A simplified controller design procedure based on asymptotic representation of the system transfer function is proposed. Using this method expressions for controller gains can be derived. A common mode model of the inverter system has been derived for low frequencies. Using this model a controller is designed to mitigate DC bus imbalance caused by sensor and ADC channel offsets. A multi-rate approach for digital implementation of PR controller with low resource consumption, that is suitable for an FPGA like digital controller ,is proposed. This multi-rate method can maintain resonance frequency accuracy even at low sampling frequency and can easily be frequency adaptive. Anti-wind up methods for PI controller have been studied to find suitable anti-wind up methods for PR controller. The tracking anti-wind up method is shown to be suitable for use with a PR controller. The effectiveness of this method under sudden disconnection and reconnection of VSI from grid is experimentally verified. A resonant integrator based second order filter is shown to be useful for active damping of LCL filter resonance with a wide range of grid inductance variation. The proposed method utilizes the LCL filter capacitor voltage to estimate resonance frequency current. Suitability of fundamental current PR controller for active damping alone, and with the proposed method show the superiority of the proposed method especially for low switching frequencies. Design oriented analysis of the above topics are included in the thesis. The theoretical understandings developed have been verified through experiments in the laboratory and can be readily implemented in industrial power electronic systems.

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37

Kumar, M. Prasanna. "Studies On Application Of Control Systems For Urban Water Networks." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/874.

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Management and supply of water in an urban water distribution system is a complex process, which include various complexities like pressure variations across the network depending on topography, demand variations depending on customers’ requirement and unaccounted water etc. Applying automatic control methods to water distribution systems is a way to improve the management of water distribution. There have been some attempts in recent years to develop optimal control algorithms to assist in the operation of complex water distribution systems. The difficulties involved by these hydraulic systems such as non-linearity, and diurnal demand patterns make the choice of a suitable automatic control method a challenge. For this purpose, this study intends to investigate the applicability of different controllers which would be able to meet the targets as quickly as possible and without creating undue transients. As a first step towards application of different controllers, PD and PID linear controllers have been designed for pump control and valve control in water distribution systems. Then a Dynamic Inversion based nonlinear controller has been designed by considering the non-linearities in the system. Here, different cases considering the effects of initial conditions used, linearization methods used, time step used for integration and selection of gains etc., have been studied before arriving at best controller. These controllers have been designed for both the flow control problems and level control problems. It is found that Dynamic Inversion-based nonlinear controller outperforms other controllers. It is well known that the performance of controllers is much dependent on the tuning of the gains (parameters). Thus in this study various alternative techniques such as Ziegler--Nichols rules (ZNPID), Genetic algorithms (GAPID) and fuzzy algorithms (FZPID) have been studied and a comparative study has been made Although with all the three gain tuning methods, required states have reached their target values, but the responses vary much in reaching to final targets. The self-tuned FZPID controller outperforms other two controllers, especially with regard to overshoots and the time taken to tune the gains for each problem. Further, an optimal DI controller is developed for the over determined case with more controls and less targets. Energy loss is considered as an objective function and normal DI controller equations are considered as constraints. Hence, an attempt is made to reduce the energy minimization in water distribution system by formulating an optimal control problem using optimal Dynamic Inversion concept. Finally, leakage reduction model is developed based on excessive pressure minimization problem by locating valves optimally as well as by setting valves optimally. For this purpose, optimization problem is solved using Pattern search algorithms and hydraulic analysis is carried out using EPANET program.

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38

Kumar, M. Prasanna. "Studies On Application Of Control Systems For Urban Water Networks." Thesis, 2008. http://hdl.handle.net/2005/874.

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Management and supply of water in an urban water distribution system is a complex process, which include various complexities like pressure variations across the network depending on topography, demand variations depending on customers’ requirement and unaccounted water etc. Applying automatic control methods to water distribution systems is a way to improve the management of water distribution. There have been some attempts in recent years to develop optimal control algorithms to assist in the operation of complex water distribution systems. The difficulties involved by these hydraulic systems such as non-linearity, and diurnal demand patterns make the choice of a suitable automatic control method a challenge. For this purpose, this study intends to investigate the applicability of different controllers which would be able to meet the targets as quickly as possible and without creating undue transients. As a first step towards application of different controllers, PD and PID linear controllers have been designed for pump control and valve control in water distribution systems. Then a Dynamic Inversion based nonlinear controller has been designed by considering the non-linearities in the system. Here, different cases considering the effects of initial conditions used, linearization methods used, time step used for integration and selection of gains etc., have been studied before arriving at best controller. These controllers have been designed for both the flow control problems and level control problems. It is found that Dynamic Inversion-based nonlinear controller outperforms other controllers. It is well known that the performance of controllers is much dependent on the tuning of the gains (parameters). Thus in this study various alternative techniques such as Ziegler--Nichols rules (ZNPID), Genetic algorithms (GAPID) and fuzzy algorithms (FZPID) have been studied and a comparative study has been made Although with all the three gain tuning methods, required states have reached their target values, but the responses vary much in reaching to final targets. The self-tuned FZPID controller outperforms other two controllers, especially with regard to overshoots and the time taken to tune the gains for each problem. Further, an optimal DI controller is developed for the over determined case with more controls and less targets. Energy loss is considered as an objective function and normal DI controller equations are considered as constraints. Hence, an attempt is made to reduce the energy minimization in water distribution system by formulating an optimal control problem using optimal Dynamic Inversion concept. Finally, leakage reduction model is developed based on excessive pressure minimization problem by locating valves optimally as well as by setting valves optimally. For this purpose, optimization problem is solved using Pattern search algorithms and hydraulic analysis is carried out using EPANET program.

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39

Pita, Duarte da Silva. "Interligação de microrredes híbridas com um conversor multinível." Master's thesis, 2021. http://hdl.handle.net/10400.13/3979.

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Nos tempos atuais a eficiência energética e a coordenação inteligente dos recursos da rede são tópicos de maior importância. As microrredes híbridas apresentam-se como uma solução interessante para a integração coordenada de fontes de geração e cargas DC ou AC nos barramentos DC ou AC respetivamente. Isto permite eliminar algumas etapas de conversão que tradicionalmente existem nas redes AC, aumentando assim a eficiência energética. Neste trabalho utilizou-se um conversor multinível para interligar uma microrrede AC a uma microrrede DC. O conversor de interligação é capaz de realizar o controlo das correntes AC, da tensão DC ou da tensão AC, dependendo dos cenários de funcionamento da microrrede híbrida. As correntes AC do conversor foram controladas através das técnicas de controlo por modo de deslizamento (MD) e modulação por largura de impulsos (PWM), partindo dos modelos das variáveis de estado do conversor. As tensões das microrredes AC e DC foram controladas utilizando malhas externas com controladores PI (Proporcional-Integral). O conversor de interligação foi simulado na plataforma MATLAB/Simulink nos três cenários de funcionamento. Os resultados de simulação foram posteriormente confirmados em laboratório através de um protótipo de baixa potência. Os resultados obtidos demonstraram uma resposta dinâmica rápida das correntes AC em ambos os métodos de controlo, com a técnica PWM a apresentar harmónicas mais reduzidas. O controlo de tensão da microrrede DC foi bem efetuado e permitiu reagir adequadamente a mudanças de referência e ao aumento do consumo da microrrede DC. No caso em que existe geração local o conversor foi capaz de realizar o equilíbrio entre a potência produzida e a potência consumida, transferindo o excesso de potência para a microrrede AC. O controlo de tensão da microrrede AC, permitiu regular de forma adequada as tensões trifásicas e reagir a mudanças de referência e variações do consumo. Energy efficiency and smart coordination of grid resources are issues of utmost importance nowadays. Hybrid microgrids are an interesting solution for the integration of AC and DC loads and generation sources in their respective AC or DC buses. This allows for a reduction of voltage conversion stages that are prevalent in the more traditional AC grid, leading to a higher efficiency. In the scope of this work a multilevel converter was used to interconnect an AC microgrid to a DC microgrid. The interlinking converter can control either the AC currents, the DC bus voltage, or the AC bus voltage, depending on the hybrid microgrid operation mode. The converter AC currents were controlled using sliding mode and pulse width modulation (PWM) techniques starting from the converter state variable representation. The AC and DC microgrid voltages were controlled by outer loop PI (Proportional Integral) controllers. The three operation modes of the interlinking converter were simulated using MATLAB/Simulink. A low power laboratory prototype was later used to further confirm the simulations results. The results showed a fast dynamic response of the AC currents, using both control techniques. PWM however resulted in reduced harmonics. The DC microgrid voltage control was successfully implemented and resulted in a good response following changes in voltage reference and DC microgrid consumption. When local power production was available, the converter was able to transfer the excess power to the AC microgrid, thus balancing the produced and consumed local power. The AC microgrid voltage control was capable of adequately regulate the three phase AC voltages and react to changes in voltage reference and local power consumption.

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40

Ghoshal, Anirban. "Operation of Three Phase Four Wire Grid Connected VSI Under Non-Ideal Conditions." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3386.

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Abstract:

The necessity to incorporate renewable energy systems into existing electric power grid and need of efficient utilization of electrical energy are growing every day. A shunt connected Voltage Source Inverter(VSI) capable of bidirectional power flow and fast control has become one of the building block to address such requirements. However with growing number of grid connected VSI, new requirements related to harmonic injection, higher overall efficiency and better performances during short term grid disturbances have emerged as challenges. For this purpose a grid connected three phase four wire VSI with LCL filter can be considered as a general module to study different control approaches and system behavior under ideal and non-ideal grid conditions. This work focuses on achieving enhanced performance by analyzing effect of non-ideal conditions on system level and relating it to individual control blocks. In this work a phase locked loop structure has been proposed which is capable of extracting positive sequence fundamental phase information under non-ideal grid conditions. It can also be used in a single phase system without any structural modification. The current control for the three phase four wire VSI system has been implemented using Proportional Resonant (PR) controller in a per phase basis in stationary reference frame. A simplified controller design procedure based on asymptotic representation of the system transfer function is proposed. Using this method expressions for controller gains can be derived. A common mode model of the inverter system has been derived for low frequencies. Using this model a controller is designed to mitigate DC bus imbalance caused by sensor and ADC channel offsets. A multi-rate approach for digital implementation of PR controller with low resource consumption, that is suitable for an FPGA like digital controller ,is proposed. This multi-rate method can maintain resonance frequency accuracy even at low sampling frequency and can easily be frequency adaptive. Anti-wind up methods for PI controller have been studied to find suitable anti-wind up methods for PR controller. The tracking anti-wind up method is shown to be suitable for use with a PR controller. The effectiveness of this method under sudden disconnection and reconnection of VSI from grid is experimentally verified. A resonant integrator based second order filter is shown to be useful for active damping of LCL filter resonance with a wide range of grid inductance variation. The proposed method utilizes the LCL filter capacitor voltage to estimate resonance frequency current. Suitability of fundamental current PR controller for active damping alone, and with the proposed method show the superiority of the proposed method especially for low switching frequencies. Design oriented analysis of the above topics are included in the thesis. The theoretical understandings developed have been verified through experiments in the laboratory and can be readily implemented in industrial power electronic systems.

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