Dissertations / Theses on the topic 'Optimum power point tracking'

Growing energy demand, depleting fossil fuels, and increasing environmental concerns lead to adaptation to clean and sustainable energy sources. Renewable energy sources are now believed to play a critical role in diminishing the deteriorating environment, supplying power to remote areas with no access to the grid, and overcoming the energy crisis by reducing the stress on existing power networks. Therefore, an upsurge in renewablesbased energy systems development has been observed during the previous few decades. In particular, solar PV technology has demonstrated extraordinary growth due to readily available solar energy, technological advancement, and a decline in costs. However, its low power conversion efficiency, intermittency, high capital cost, and low power quality are the major challenges in further uptake. This research intends to enhance the overall performance of PV systems by providing novel solutions at all levels of a PV system hierarchy. The first level investigated is the solar energy to PV power conversion, where an efficient maximum power point tracking (MPPT) method is developed. Secondly, the dc to ac power conversion is explored, and an optimal PV system sizing approach with abidance to power quality constraints is developed. Finally, smart power management strategies are investigated to utilise the energy produced by solar PV efficiently, such that the minimum cost of energy can be achieved while considering various technical constraints. The methods involve Genetic Algorithm (GA) for finding the optimal parameters, mathematical models, MATLAB/Simulink simulations of solar PV system (including PV arrays, dc/dc converter with MPPT, batteries, dc/ac inverter, and electric load), and experimental testing of the developed MPPT method and power management strategies at the smart energy lab, Edith Cowan University. Highly dynamic weather and electricity consumption data encompassing multiple seasons are used to test the viability of the developed methods. The results exhibit that the developed hybrid MPPT technique outperforms the conventional techniques by offering a tracking efficiency of above 99%, a tracking speed of less than 1s and almost zero steady-state oscillations under rapidly varying environmental conditions. Additionally, the developed MPPT technique can also track the global maximum power point during partial shading conditions. The analyses of power quality at the inverter’s terminal voltage and current waveforms revealed that solar PV capacity, battery size, and LC filter parameters are critical for the reliable operation of a solar PV system and may result in poor power quality leading to system failure if not selected properly. On the other hand, the optimal system parameters found through the developed methodology can design a solar PV system with minimum cost and conformance to international power quality standards. The comparison between the grid-connected and stand-alone solar PV system reveals that for the studied case, the grid-connected system is more economical than the stand-alone system but outputs higher life cycle emissions. It was also found that for grid tied PV systems, minimum cost of energy can be achieved at an optimal renewable to grid ratio. Additionally, applying a time varying tariff yields a slightly lower energy cost than the anytime flat tariff. A sensitivity analysis of the reliability index, i.e., loss of power supply probability (LPSP), demonstrates that for the stand-alone PV systems, there is an inverse relationship between LPSP and cost of energy. Contrarily, for grid-connected systems, the cost of energy does not vary significantly with the change in LPSP.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.<br>Includes bibliographical references (p. 79-80).<br>This thesis describes the design, and validation of a maximum power point tracking DC-DC converter capable of following the true global maximum power point in the presence of other local maximum. It does this without the use of costly components such as analog-to-digital converters and microprocessors. It substantially increases the efficiency of solar power conversion by allowing solar cells to operate at their ideal operating point regardless of changes in load, and illumination. The converter switches between a dithering algorithm which tracks the local maximum and a global search algorithm for ensuring that the converter is operating at the true global maximum.<br>by Joseph Duncan.<br>M.Eng.

This thesis begins with providing a basic introduction of electricity requirements for small developing country communities serviced by small scale generating units (focussing mainly on small wind turbine, small Photo Voltaic system and Micro-Hydro Power Plants). Scenarios of these small scale units around the world are presented. Companies manufacturing different size wind turbines are surveyed in order to propose a design that suits the most abundantly available and affordable turbines. Different Maximum Power Point Tracking (MPPT) algorithms normally employed for these small scale generating units are listed along with their working principles. Most of these algorithms for MPPT do not require any mechanical sensors in order to sense the control parameters like wind speed and rotor speed (for small wind turbines), temperature and irradiation (for PV systems), and water flow and water head (for Micro-Hydro). Models for all three of these systems were developed in order to generate Maximum Power Point (MPP) curves. Similarly, a model for Permanent Magnet Synchronous Generators (PMSGs) has been developed in the d-q reference frame. A boost rectifier which enables active Power Factor Correction (PFC) and has a DC regulated output voltage is proposed before implementing a MPPT algorithm. The proposed boost rectifier works on the principle of Direct Power Control Space Vector Modulation (DPC-SVM) which is based on instantaneous active and reactive power control loops. In this technique, the switching states are determined according to the errors between commanded and estimated values of active and reactive powers. The PMSG and Wind Turbine behaviour are simulated at various wind speeds. Similarly, simulation of the proposed PFC boost rectifier is performed in matlab/simulink. The output of these models are observed for the variable wind speeds which identifies PFC and boosted constant DC output voltage is obtained. A buck converter that employs the MPPT algorithm is proposed and modeled. The model of a complete system that consists of a variable speed small wind turbine, PMSG, DPC-SVM boost rectifier, and buck converter implementing MPPT algorithm is developed. The proposed MPPT algorithm is based upon the principle of adjusting the duty ratio of the buck converter in order reach the MPP for different wind speeds (for small wind turbines) and different water flow rates (Micro-Hydro). Finally, a prototype DPC-SVM boost rectifier and buck converter was designed and built for a turbine with an output power ranging from 50 W-1 kW. Inductors for the boost rectifier and buck DC-DC converter were designed and built for these output power ranges. A microcontroller was programmed in order to generate three switching signals for the PFC boost rectifier and one switching signal for the MPPT buck converter. Three phase voltages and currents were sensed to determine active and reactive power. The voltage vectors were divided into 12 sectors and a switching algorithm based on the DPC-SVM boost rectifier model was implemented in order to minimize the errors between commanded and estimated values of active and reactive power. The system was designed for charging 48 V battery bank. The generator three phase voltage is boosted to a constant 80 V DC. Simulation results of the DPC-SVM based rectifier shows that the output power could be varied by varying the DC load maintaining UPF and constant boosted DC voltage. A buck DC-DC converter is proposed after the boost rectifier stage in order to charge the 48 V battery bank. Duty ratio of the buck converter is varied for varying the output power in order to reach the MPP. The controller prototype was designed and developed. A laboratory setup connecting 4 kW induction motor (behaving as a wind turbine) with 1kW PMSG was built. Speed-torque characteristic of the induction motor is initially determined. The torque out of the motor varies with the motor speed at various motor supply voltages. At a particular supply voltage, the motor torque reaches peak power at a certain turbine speed. Hence, the control algorithm is tested to reach this power point. Although the prototype of the entire system was built, complete results were not obtained due to various time constraints. Results from the boost rectifier showed that the appropriate switching were performed according to the digitized signals of the active and reactive power errors for different voltage sectors. Simulation results showed that for various wind speed, a constant DC voltage of 80 V DC is achieved along with UPF. MPPT control algorithm was tested for induction motor and PMSG combination. Results showed that the MPPT could be achieved by varying the buck converter duty ratio with UPF achieved at various wind speeds.

Operating faraway from maximum power point decreases the generated power from photovoltaic (PV) system. For optimum operation, it is necessary to continually track the maximum power point of the PV solar array. However with huge changes in external influences and the nonlinear relationship of electrical characteristics of PV panels it is a difficult problem to identify the maximum power point as a function of these influences. Many tracking control strategies have been proposed to track maximum power point such as perturb and observe, incremental conductance, parasitic capacitance, and neural networks. These proposed methods have some disadvantages such as high cost, difficulty, complexity and nonstability. This thesis presents a novel approach based on Adaptive NeuroFuzzy Inference System (ANFIS) to predict the maximum power point utilising the actual field data, which is performed in different environmental conditions. The short circuit current and open circuit voltage are used as inputs to PV panels instead of solar irradiation and cell junction temperature. The predicted $V_{max}$from ANFIS model is used as a reference voltage for fuzzy logic controller (FLC). The FLC is used to adjust the duty cycle of the electronic switch of two types of DC-DC converter. These DC-DC converters are used to interface between the load voltage and PV panels. The duty cycle of the electronic switch of the DC-DC converter is adjusted until the input voltage of the converter tracks the predicted $V_{max}$of the PV system. FLC rules and membership functions are designed to achieve the most promising performance at different environmental conditions, different load types and different rate of changes in the duty cycle of Buck-Boost and Buck converters. The membership functions and fuzzy rules of FLC are designed to balance between different required features such as quick tracking under different environmental conditions, high accuracy, stability and high efficiency.

In recent years, wind energy technology has become one of the top areas of interest for energy harvesting in the power electronics world. This interest has especially peaked recently due to the increasing demand for a reliable source of renewable energy. In a recent study, the American Wind Energy Association (AWEA) ranked the U.S as the leading competitor in wind energy harvesting followed by Germany and Spain. Although the United States is the leading competitor in this area, no one has been able successfully develop an efficient, low-cost AC/DC convertor for low power turbines to be used by the average American consumer. There has been very little research in low power AC/DC converters for low to medium power wind energy turbines for battery charging applications. Due to the low power coefficient of wind turbines, power converters are required to transfer the maximum available power at the highest efficiency. Power factor correction (PFC) and maximum power point tracking (MPPT) algorithms have been proposed for high power wind turbines. These turbines are out of the price range of what a common household can afford. They also occupy a large amount of space, which is not practical for use in one's home. A low cost AC/DC converter with efficient power transfer is needed in order to promote the use of cheaper low power wind turbines. Only MPPT is implemented in most of these low power wind turbine power converters. The concept of power factor correction with MPPT has not been completely adapted just yet. The research conducted involved analyzing the effect of power factor correction and maximum power point tracking algorithm in AC/DC converters for wind turbine applications. Although maximum power to the load is always desired, most converters only take electrical efficiency into consideration. However, not only the electrical efficiency must be considered, but the mechanical energy as well. If the converter is designed to look like a purely resistive load and not a switched load, a wind turbine is able to supply the maximum power with lower conduction loss at the input side due to high current spikes. Two power converters, VIENNA with buck converter and a Buck-boost converter, were designed and experimentally analyzed. A unique approach of controlling the MPPT algorithm through a conductance G for PFC is proposed and applied in the VIENNA topology. On the other hand, the Buck-boost only operates MPPT. With the same wind profile applied for both converters, an increase in power drawn from the input increased when PFC was used even when the power level was low. Both topologies present their own unique advantages. The main advantage for the VIENNA converter is that PFC allowed more power extraction from the turbine, increasing both electrical and mechanical efficiency. The buck-boost converter, on the other hand, presents a very low component count which decreases the overall cost and volume. Therefore, a small, cost-effective converter that maximizes the power transfer from a small power wind turbine to a DC load, can motivate consumers to utilize the power available from the wind.<br>M.S.E.E.<br>School of Electrical Engineering and Computer Science<br>Engineering and Computer Science<br>Electrical Engineering MSEE

An investigation into the design of a stand-alone photovoltaic water pumping system for supplying rural areas is presented. It includes a study of system components and their modelling. The PV water pumping system comprises a solar-cell-array, DC-DC buck chopper and permanent-magnet DC motor driving a centrifugal pump. The thesis focuses on increasing energy extraction by improving maximum power point tracking (MPPT). From different MPPT techniques previously proposed, the perturb and observe (P&O) technique is developed because of its ease of implementation and low implementation cost. A modified variable step-size P&O MPPT algorithm is investigated which uses fuzzy logic to automatically adjust step-size to better track maximum power point. Two other MPPT methods are investigated: a new artificial neural network (ANN) method and fuzzy logic (FL) based method. These use PV source output power and the speed of the DC pump motor as input variables. Both generate pulse width modulation (PWM) control signals to continually adjust the buck converter to maximize power from the PV array, and thus motor speed and the water discharge rate of a centrifugal pump. System elements are individually modelled in MATLAB/SIMULINK and then connected to assess performance under different PV irradiation levels. First, the MP&O MPPT technique is compared with the conventional P&O MPPT algorithm. The results show that the MP&O MPPT has faster dynamic response and eliminates oscillations around the MPP under steady-state conditions. The three proposed MPPT methods are implemented in the simulated PV water pumping system and compared. The results confirm that the new methods have improved energy extraction and dynamic tracking compared with simpler methods.

<p> The SIUe solar car team lacks a competitive communication system. To enable the competitive edge a major upgrade to the electronics and wiring was required. A new maximum power point tracker and driver support system was developed to give them the competitive edge.</p>

This thesis proposes a new maximum power point tracking (MPPT) method for photovoltaic (PV) systems using Kalman filter. The Perturbation & Observation (P&O) method is widely used due to its easy implementation and simplicity. The P&O usually requires a dithering scheme to reduce noise effects, but the dithering scheme slows the tracking response time. Tracking speed is the most important factor for improving efficiency under frequent environmental change. The proposed method is based on the Kalman filter. An adaptive MPPT algorithm which uses an instantaneous power slope has introduced, but process and sensor noises disturb its estimations. Thus, applying the Kalman filter to the adaptive algorithm is able to reduce tracking failures by the noises. It also keeps fast tracking performance of the adaptive algorithm, so that enables using the Kalman filter to generate more powers under rapid weather changes than using the P&O. For simulations, a PV system is introduced with a 30kW array and MPPT controller designs using the Kalman filter and P&O. Simulation results are provided the comparison of the proposed method and the P&O on transient response for sudden system restart and irradiation changes in different noise levels. The simulations are also performed using real irradiance data for two entire days, one day is smooth irradiance changes and the other day is severe irradiance changes. The proposed method has showed the better performance when the irradiance is severely fluctuating than the P&O while the two methods have showed the similar performances on the smooth irradiance changes.<br>Master of Science

La creixent demanda energètica, l’esgotament dels combustibles fòssils i l’augment de l’escalfament global a causa de l’emissió de carboni ha donat lloc a la necessitat d’un sistema energètic alternatiu, global i respectuós amb el medi ambient. L’energia solar es considera una de les formes d’energia més inesgotables d’aquest univers, però té el problema de la baixa eficiència a causa de les diferents condicions ambientals. El panell solar presenta un comportament no lineal en condicions climàtiques reals i la potència de sortida fluctua amb la variació de la irradiació solar i la temperatura. El canvi de les condicions meteorològiques i el comportament no lineal dels sistemes fotovoltaics suposen un repte en el seguiment de diferents PowerPoint màxims. Per tant, per extreure i lliurar contínuament la màxima potència possible del sistema fotovoltaic, en determinades condicions ambientals, s’ha de formular l’estratègia de control de seguiment del punt de potència màxima (MPPT) que funcioni contínuament el sistema fotovoltaic al seu MPP. Es necessita un controlador no lineal robust per garantir el MPPT mitjançant la manipulació de les línies no lineals d’un sistema i el fa robust contra les condicions ambientals canviants. El control de mode lliscant (SMC) s’utilitza àmpliament en sistemes de control no lineals i s’ha implementat en sistemes fotovoltaics (PVC) per rastrejar MPP. SMC és robust contra les pertorbacions, les incerteses del model i les variacions paramètriques. Representa fenòmens indesitjables com el xerramec, inherent al fet que provoca pèrdues d’energia i calor. En aquesta tesi, en primer lloc, es formula un controlador SMC d’ordre sencer per extreure la màxima potència d’un sistema solar fotovoltaic en condicions climàtiques variables que utilitzen l’esquema MPPT de pertorbació i observació (P \ & O) del sistema fotovoltaic autònom proposat. El sistema proposat consta de dos esquemes de bucles, a saber, el bucle de cerca i el bucle de seguiment. P&O MPPT s’utilitza al bucle de cerca per generar el senyal de referència i un controlador SMC de seguiment s’utilitza a l’altre bucle per extreure la màxima potència fotovoltaica. El sistema fotovoltaic es connecta amb la càrrega mitjançant el convertidor d’alimentació electrònic DC-DC de potència. Primer es deriva un model matemàtic del convertidor d’augment i, basat en el model derivat, es formula un SMC per controlar els impulsos de la porta del commutador del convertidor d’augment. L’estabilitat del sistema de bucle tancat es verifica mitjançant el teorema d’estabilitat de Lyapunov. L’esquema de control proposat es prova amb diferents nivells d’irradiació i els resultats de la simulació es comparen amb el controlador de derivades integrals proporcionals clàssiques (PID). El SMC clàssic representa fenòmens indesitjables com el xerramec, inherent al fet que provoca pèrdues d’energia i calor. A la següent part d’aquesta tesi, es discuteix el disseny del controlador de mode lliscant adaptatiu (ASMC) per al sistema fotovoltaic proposat. El control adoptat s’executa mitjançant un ASMC i la millora s’actualitza mitjançant un algorisme d’optimització MPPT de mètode de cerca de patrons millorats (IPSM). S’utilitza un MPPT IPSM per generar la tensió de referència per tal de comandar el controlador ASMC subjacent. S’ha dut a terme una comparació amb altres dos algoritmes d’optimització, a saber, Perturb \ & Observe (P&O) i Particle Swarm Optimization (PSO) amb IPSM per MPPT. Com a estratègia no lineal, l’estabilitat del controlador adaptatiu es garanteix mitjançant la realització d’una anàlisi de Lyapunov. El rendiment de les arquitectures de control proposades es valida comparant les propostes amb la del conegut i àmpliament utilitzat controlador PID.<br>La creciente demanda de energía, el agotamiento de los combustibles fósiles y el aumento del calentamiento global debido a la emisión de carbono han hecho surgir la necesidad de un sistema energético alternativo, de eficiencia general y respetuoso con el medio ambiente. La energía solar se considera una de las formas de energía más inagotables de este universo, pero tiene el problema de la baja eficiencia debido a las diferentes condiciones ambientales. El panel solar exhibe un comportamiento no lineal en condiciones climáticas reales y la potencia de salida fluctúa con la variación de la irradiancia solar y la temperatura. Las condiciones climáticas cambiantes y el comportamiento no lineal de los sistemas fotovoltaicos plantean un desafío en el seguimiento de la variación máxima de PowerPoint. Por lo tanto, para extraer y entregar continuamente la máxima potencia posible del sistema fotovoltaico, en determinadas condiciones ambientales, se debe formular la estrategia de control de seguimiento del punto de máxima potencia (MPPT) que opere continuamente el sistema fotovoltaico en su MPP. Se requiere un controlador no lineal robusto para asegurar MPPT manejando las no linealidades de un sistema y haciéndolo robusto frente a condiciones ambientales cambiantes. El control de modo deslizante (SMC) se usa ampliamente en sistemas de control no lineales y se ha implementado en sistemas fotovoltaicos (PVC) para rastrear MPP. SMC es robusto contra perturbaciones, incertidumbres del modelo y variaciones paramétricas. Representa fenómenos indeseables como el parloteo, inherentes a él, que provocan pérdidas de energía y calor. En esta tesis, en primer lugar, se formula un controlador SMC de orden entero para extraer la máxima potencia de un sistema fotovoltaico solar en condiciones climáticas variables empleando el esquema MPPT de perturbar y observar (P&O) para el sistema fotovoltaico autónomo propuesto. El sistema propuesto consta de dos esquemas de bucles, a saber, el bucle de búsqueda y el bucle de seguimiento. P&O MPPT se utiliza en el bucle de búsqueda para generar la señal de referencia y se utiliza un controlador SMC de seguimiento en el otro bucle para extraer la máxima potencia fotovoltaica. El sistema fotovoltaico está conectado con la carga a través del convertidor elevador DC-DC electrónico de potencia. Primero se deriva un modelo matemático del convertidor elevador y, en base al modelo derivado, se formula un SMC para controlar los pulsos de puerta del interruptor del convertidor elevador. La estabilidad del sistema de circuito cerrado se verifica mediante el teorema de estabilidad de Lyapunov. El esquema de control propuesto se prueba bajo diferentes niveles de irradiancia y los resultados de la simulación se comparan con el controlador clásico proporcional integral derivado (PID). El SMC clásico describe fenómenos indeseables como el parloteo, inherente a él, que causa pérdidas de energía y calor. En la siguiente parte de esta tesis, se analiza el diseño del controlador de modo deslizante adaptativo (ASMC) para el sistema fotovoltaico propuesto. El control adoptado se ejecuta utilizando un ASMC y la mejora se actualiza utilizando un algoritmo de optimización MPPT del Método de búsqueda de patrón mejorado (IPSM). Se utiliza un IPSM MPPT para generar el voltaje de referencia para controlar el controlador ASMC subyacente. Se ha realizado una comparación con otros dos algoritmos de optimización, a saber, Perturb \ Observe (P&O) y Particle Swarm Optimization (PSO) con IPSM para MPPT. Como estrategia no lineal, la estabilidad del controlador adaptativo está garantizada mediante la realización de un análisis de Lyapunov.<br>The increasing energy demands, depleting fossil fuels, and increasing global warming due to carbon emission has arisen the need for an alternate, overall efficiency, and environment-friendly energy system. Solar energy is considered to be one of the most inexhaustible forms of energy in this universe, but it has the problem of low efficiency due to varying environmental conditions. Solar panel exhibits nonlinear behavior under real climatic conditions and output power fluctuates with the variation in solar irradiance and temperature. Changing weather conditions and nonlinear behavior of PV systems pose a challenge in the tracking of varying maximum PowerPoint. Hence, to continuously extract and deliver the maximum possible power from the PV system, under given environmental conditions, the maximum power point tracking (MPPT) control strategy needs to be formulated that continuously operates the PV system at its MPP. A robust nonlinear controller is required to ensure MPPT by handling nonlinearities of a system and making it robust against changing environmental conditions. Sliding mode control (SMC) is extensively used in non-linear control systems and has been implemented in photovoltaic systems (PV) to track MPP. SMC is robust against disturbances, model uncertainties, and parametric variations. It depicts undesirable phenomena like chattering, inherent in it causing power and heat losses. In this thesis, first, an integer order SMC controller is formulated for extracting maximum power from a solar PV system under variable climatic conditions employing the perturb and observe (P&O) MPPT scheme for the proposed stand-alone PV system. The proposed system consists of two loops schemes, namely the searching loop and the tracking loop. P&O MPPT is utilized in the searching loop to generate the reference signal and a tracking SMC controller is utilized in the other loop to extract the maximum PV power. PV system is connected with load through the power electronic DC-DC boost converter. A mathematical model of the boost converter is derived first, and based on the derived model, an SMC is formulated to control the gate pulses of the boost converter switch. The closed-loop system stability is verified through the Lyapunov stability theorem. The proposed control scheme is tested under varying irradiance levels and the simulation results are compared with the classical proportional integral derivative (PID) controller. Classical SMC depicts undesirable phenomena like chattering, inherent in it causing power and heat losses. In the next part of this thesis, the design of the adaptive sliding mode controller (ASMC) is discussed for the proposed PV system. The adopted control is executed utilizing an ASMC and the enhancement is actualized utilizing an Improved Pattern Search Method (IPSM) MPPT optimization algorithm. An IPSM MPPT is used to generate the reference voltage in order to command the underlying ASMC controller. Comparison with two other optimization algorithms, namely, a Perturb & Observe (P&O) and Particle Swarm Optimization (PSO) with IPSM for MPPT has been conducted. As a non-linear strategy, the stability of the adaptive controller is guaranteed by conducting a Lyapunov analysis. The performance of the proposed control architectures is validated by comparing the proposals with that of the well-known and widely used PID controller. The simulation results validate that the proposed controller effectively improves the voltage tracking, system power with reduced chattering effect, and steady-state error. A tabular comparison is provided at the end of each optimization algorithm category as a resume quantitative comparison. It is anticipated that this work will serve as a reference and provides important insight into MPPT control of the PV systems.

In grid connected photovoltaic (PV) generation systems, inverters are used to convert the generated DC voltage to an AC voltage. An additional dc-dc converter is usually connected between the PV source and the inverter for Maximum Power Point Tracking (MPPT). An iterative MPPT algorithm searches for the optimum operating point of PV cells to maximise the output power under various atmospheric conditions. It is desirable to be able to represent the dynamics of the changing PV power yield within stability studies of the AC network. Unfortunately MPPT algorithms tend to be nonlinear and/or time-varying and cannot be easily combined with linear models of other system elements. In this work a new MPPT technique is developed in order to enable linear analysis of the PV system over reasonable time scales. The new MPPT method is based on interpolation and an emulated-load control technique. Numerical analysis and simulations are employed to develop and refine the MPPT. The small-signal modelling of the MPPT technique exploits the fact that the emulated-load control technique can be linearised and that short periods of interpolation can be neglected. A small-signal PV system model for variable irradiation conditions was developed. The PV system includes a PV module, a dc-dc boost converter, the proposed controller and a variety of possible loads. The new model was verified by component-level time-domain simulations. Be cause measured signals in PV systems contain noise, it is important to assess the impact of that noise on the MPPT and design an algorithm that operates effectively in pr esence of noise. For performance assessment of the new MPPT techniques, the efficiencies of various MPPT techniques in presence of noise were compared. This comparison showed superiority of the interpolation MPPT and led to conclusions about effective use of existing MPPT methods. The new MPPT method was also experimentally tested.

Av den frigjorda energin för en lastbils bränsle är omkring 30% i form avspillvärme i avgassystemet. Med implementation av ett spillvärmeåtervinningsystem går det att återvinna en del av den frigjorda energin i form av elektricitet till lastbilens elsystem. Två termoelektriska generatorer använder avgaserna som värmekälla och ett kylmedel som kall källa för att åstakomma en temperaturdifferans i generatorerna. Med hjälp av Seebeck-effekten går det att omvandla temperaturdifferansen till elektricitet och på så sätt avlastas motorns generator vilket medför en lägre bränsleförbrukning. Detta examensarbete innefattar utvecklandet av en funktion som maximerar nettoeffekten utvunnen från systemet. Funktionen som utvecklats är döpt till Maximum Net-power Point Tracking (MNPT) och har som uppgift att beräkna referensvärden som styrningen av systemet skall uppnå för att få ut maximal nettoeffekt. En simuleringmiljö i Matlab/Simulink är uppbyggd för att kunna implementera en kontrollstrategi för styrningen av kylmedlet samt avgasledning via bypass-ventiler. Systemet har blivit implementerat i en motorstyrenhet på en testrack somkommunicerar via CAN där givare så som temperatur och tryck avläses. Systemet har ej blivit implementerat på lastbilen då samtliga fysiska komponenter ej blev färdigställda under examensarbetets gång. En fallstudie genomfördes i simuleringsmiljön och resultaten visade att användningen av en MNPT-funktion tillät upp till 300% ökning av den återinförda nettoeffekten till lastbilens elsystem jämfört med utan användning av kontrollalgoritmer, och upp till 50% ökning jämfört med statiska referensvärden.<br>About 30% of the released energy of a truck’s fuel is waste heat in the exhaustsystem. It is possible to recover some of the energy with a waste heat recovery system that generates electricity from a temperature difference by utilising the Seebeck-effect. Two thermoelectric generators are implemented on a truck and utilises the exhaust gas as a heat source and the coolant fluid as a cold source to accomplish a temperature difference in the generators. The electricity is reintroduced to the truck’s electrical system and thus reducing the load on the electrical generator in the engine which results in lower fuel consumption. This thesis includes the construction of a function that maximises the netpowerderived from the system. The function developed is named Maximum Net Power Point Tracking (MNPT) and has the task of calculating reference values that the controllers of the system must achieve in order to obtain maximumnet-power. A simulation environment has been developed in Matlab/Simulink in order to design a control strategy to three valves and one pump. The system has been implemented on a engine control unit that has been mounted on a test rack. The engine control unit communicates through CAN to connected devices. The system has not been implemented on the truck due that all the physical components were not completed during the time of the thesis. A case study has been conducted and the results proves that the use of an MNPT-function allows up to 300% increase in regenerated net power into the trucks electrical system compared with no control algorithms, and up to 50% compared with static reference values.

The increase in demand for renewable energy sources has been exponential in recent years and is mainly driven by factors that include the growth of greenhouse emissions and the decline in fossil fuel reservoirs. Photovoltaic (PV) energy, one of the more prominent renewable energy sources, produces electricity directly from sunlight, noiselessly and harmlessly to the environment. Additionally, PV energy systems are easy to install and financially supported by many governments, which has helped disseminate PV technology worldwide. The total generated power from PV installations (and the number of installations) has increased more than two-fold during the past 3 years, so that now more than 177 GW of PV-generated power is delivered per year. Researchers have been led to work on the obstacles facing PV systems from different perspectives, including: installation cost, inconsistency, and conversion and interface efficiency. The aim of this thesis is to design a high-efficiency PV inverter system configuration. The contribution to the knowledge in this thesis can be divided into two parts. The first part contains a critical analysis of different maximum power point tracking (MPPT) techniques. The second part provides a detailed design of the inverter system, which consists of a boost converter and a low-frequency H-bridge. Together, the three parts in this contribution present a complete high efficiency PV inverter system. The proposed system maintains high-efficiency energy delivery by reducing the number of high-frequency switches, which waste a significant amount of energy and reduce system efficiency. In order to show the superiority of the proposed configuration, a power loss analysis comparison with the other existing configurations is presented. In addition, different scenarios have been simulated with Matlab/Simulink. The results of these simulations confirm the distinction of the proposed configuration as well as its low-loss, high-efficiency characteristics which is rated at 98.8%.

This master work was focused on modelling and investigation of a photovoltaic module which operates in non-uniform solar irradiance and temperature changes which is typical to Lithuanian climate. 60 polycrystalline silicon cells were used to model photovoltaic module. Matlab®/Simulink® was used for modelling and calculating the whole system. To generate solar insolation curve, the latitude, longitude of the geographic place and a number of days in a year have to be selected. Buck-boost DC-DC converter and hill-climbing maximum power point tracking algorithm was used to produce maximum power point of the photovoltaic module. Modeled system has reached 93.95 % of maximum power from the photovoltaic module. Structure: introduction, review of maximum power point algorithms, system modelling, research results, conclusions, references. The thesis consists of: 60 pages, 41 figures, 16 tables, 37 references. Appendixes included.<br>Šiame magistro darbe buvo sumodeliuotas ir ištirtas fotovoltinio modulio veikimas, veikiant Lietuvoje būdingiems saulės apšvietos ir temperatūros pokyčiams. Fotovoltinį modulį sudaro 60 polikristalinių silicio celių sujungtų nuosekliai sistema. Modeliavimui ir skaičiavimas atlikti buvo naudojamas Matlab®/Simulink® programinės įrangos paketas. Įvedus vietos ilgumą, platumą ir pasirinkus metų dieną sugeneruojama saulės apšvietos kreivė paros bėgyje. Išgauti maksimalią galią iš fotovoltinio elemento buvo pasirinkta „buck-boost“ tipo įtampos keitiklis ir „Kalno-kilimo“ didžiausios galios taško algoritmas. Naudojant pasirinkto tipo įtampos keitiklį ir algoritmą galima pasiekti iki 93,95 % maksimalios galios. Darbą sudaro 7 dalys: įvadas, maksimalios galios algoritmų literatūros apžvalga, sistemos modeliavimas, maksimalios galios algoritmo sudarymas, rezultatai, išvados, literatūros sąrašas. Darbo apimtis 60 puslapiai, 2 priedai, 41 iliustracijų 16 lentelių, 37 bibliografiniai šaltiniai.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2017.<br>Submitted by Raquel Almeida (raquel.df13@gmail.com) on 2017-07-31T12:20:03Z No. of bitstreams: 1 2017_RamsayRafaelMacDonald.pdf: 4803485 bytes, checksum: 10d4b13dca72d536ac829226796346ba (MD5)<br>Approved for entry into archive by Raquel Viana (raquelviana@bce.unb.br) on 2017-09-11T16:28:58Z (GMT) No. of bitstreams: 1 2017_RamsayRafaelMacDonald.pdf: 4803485 bytes, checksum: 10d4b13dca72d536ac829226796346ba (MD5)<br>Made available in DSpace on 2017-09-11T16:28:58Z (GMT). No. of bitstreams: 1 2017_RamsayRafaelMacDonald.pdf: 4803485 bytes, checksum: 10d4b13dca72d536ac829226796346ba (MD5) Previous issue date: 2017-09-11<br>O projeto Hydro-K tem como objetivo o desenvolvimento de uma turbina hidrocinética. O protótipo ou o modelo preliminar desta certamente apresenta incertezas e para eliminá-las são necessários testes e coleta de dados. Essa coleta foi feita através de uma plataforma instrumental desenvolvida neste trabalho. Um outro desafio foi o controle da turbina. O controle tradicional das turbinas hidrocinéticas com um eixo horizontal, velocidade variável e um angulo da pá fixo, requer o mapeamento da curva CP da turbina com antecedência. Em seguida, a sua velocidade de rotação é medida e manipulada de modo a manter a máxima eficiência do rotor. Recentemente, o controle do Maximum Power Point Tracking (MPPT) foi aplicado às turbinas eólicas. Esse método de controle elimina a necessidade de mapeamento de curva CP medindo a tensão e a saída de corrente do gerador e ajustando periodicamente a carga elétrica no gerador para manter a potência máxima de saída elétrica. Considerando as semelhanças entre as turbinas hidrocinéticas e as eólicas, é provável que o MPPT possa ser aplicado para os hidrogeradores. Um segundo objetivo desta dissertação é avaliar a eficácia do MPPT para turbinas hidrocinéticas comparando uma estratégia de controle convencional com o MPPT usando simulações no "SIMULINK". A carga elétrica no gerador é variada usando o Pulse Width Modulation (PWM). A turbina hidrocinética do Hydro-K desenvolvida na Universidade de Brasília (UnB) é equipada com um gerador síncrono-trifásico com ímã permanente. Os resultados das simulações e experiências são apresentados comparando os dois métodos de controle acima mencionados sob diferentes condições de velocidade da água, e mostram que o controle MPPT fornece uma saída elétrica superior.<br>A project named Hydro-K is aimed at developing a hydrokinetic turbine. The prototype or preliminary model of this turbine will inherently present uncertainties. Eliminating them requires testing and data gathering. The data is acquired using an instrumentation platform designed in this dissertation. Another challenge will be controlling the turbine. Controlling traditional horizontal-axis-variable-speed-fixed-pitch hydrokinetic turbines requires mapping its efficiency at various water and rotor speeds, i.e., the CP curve of the turbine, in advance. Whereafter, its rotational velocity is measured and manipulated in order to maintain maximum efficiency of the rotor. Recently, Maximum Power Point Tracking (MPPT) control has been applied to wind turbines. This control method eliminates the necessity of CP curve mapping by measuring the generator’s voltage and current output, and periodically adjusting the electrical load on the generator to maintain the maximum electrical power output. Considering the similarities between hydrokinetic and wind turbines, it is likely that MPPT can be effectively applied for the hydrokinetic variant. Therefore, a second objective is assessing the effectiveness of MPPT for hydrokinetic turbines by comparing a conventional control strategy with MPPT using simulations in "SIMULINK". The electrical load on the generator is varied by using Pulse Width Modulation (PWM). The Hydro-K turbine developed at the University of Brasilia (UnB) is equipped with a three-phase-permanent-magnet-synchronous- generator (PMSG). The results of the simulations are presented by comparing the two aforementioned control methods under different water velocity conditions, and show that MPPT control delivers a superior electrical output.

In this thesis, a maximum power point tracking (MPPT) for multiple input single output (MISO) converter is presented such that power generated from multiple individual energy sources can be combined to deliver the maximum amount of power to a common resistive load. Typically, MISO converters will employ techniques that yield equal current sharing from each energy source. However, this may not be desirable since each source may be rated at different power ratings and/or may experience different operating conditions, preventing the system MISO converter to acquire the most available total power from the sources. Utilizing MPPT control would therefore be beneficial in maximizing the output power of the MISO converter system. In this thesis, a proposed two-stage converter system is presented to incorporate the MPPT control in the MISO system. The initial stage implements the MPPT, drawing as much power from the corresponding source. The second stage regulates the output voltage of the MPPT. To evaluate the performance and efficiency of the proposed system, simulation with two solar panels as the sources was performed using Simulink with various test cases to fully explore the viability of the system. Simulation results were also used to compare with those obtained from a system without the MPPT. Results show that the proposed system with the MPPT stage is able to improve input regulation and increase the total amount of power acquired from the sources compared to the system without the MPPT. Further testing with hardware setup confirms the simulation results and demonstrates that even with large differences in input powers, the most total amount of power is achieved and utilized.

This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf<br>Bachelors<br>Engineering and Computer Science<br>Electrical Engineering

碩士<br>聖約翰科技大學<br>電機工程系碩士在職專班<br>104<br>This thesis presents a novel maximum power point tracking technique for photovoltaic. The proposed technique adjusts the operating point of a photovoltaic panel based on three physical characteristics of the photovoltaic panel: (a) the incremental surface temperature is positive correlation with the variation of sunlight intensity; (b) the normalized incremental voltage is greater than the normalized incremental current at the left-hand side of the maximum power point; and (c) the normalized incremental current is greater than the normalized incremental voltage at the right-hand side of the maximum power point. The proposed technique can correctly determine the operating point of a photovoltaic panel in rapidly changed irradiation, to improve the misjudgment defect of traditional techniques. The proposed technique enables photovoltaic panels can work close to the maximum power point under different sunlight intensity, to increase the electricity generation and efficiency of photovoltaic panels.

Solar photovoltaic (PV) systems are distributed energy sources that are an environmentally friendly and renewable source of energy. However, solar PV power fluctuates due to variations in radiation and temperature levels. Furthermore, when the solar panel is directly connected to the load, the power that is delivered is not optimal. A maximum peak power point tracker is therefore necessary for maximum efficiency. A complete PV system equipped maximum power point tracking (MPPT) system includes a solar panel, MPPT algorithm, and a DC-DC converter topology. Each subsystem is modeled and simulated in a Matlab/Simulink environment; then the whole PV system is combined with the battery load to assess the overall performance when subjected to varying weather conditions. A PV panel model of moderate complexity based on the Shockley diode equation is used to predict the electrical characteristics of the cell with regard to changes in the atmospheric parameter of irradiance and temperature. In this dissertation, five MPPT algorithms are written in Matlab m-files and investigated via simulations. The standard Perturb and Observe (PO) algorithm along with its two improved versions and the conventional Incremental Conductance (IC) algorithm, also with its two-stage improved version, are assessed under different atmospheric operating conditions. An efficient two-mode MPPT algorithm combining the incremental conductance and the modified constant voltage methods is selected from the five ones as the best model, because it provides the highest tracking efficiencies in both sunny and cloudy weather conditions when compared to other MPPT algorithms. A DC-DC converter topology and interface study between the panel and the battery load is performed. This includes the steady state and dynamic analysis of buck and boost converters and allows the researcher to choose the appropriate chopper for the current PV system. Frequency responses using the state space averaged model are obtained for both converters. They are displayed with the help of Bode and root locus methods based on their respective transfer functions. Following the simulated results displayed in Matlab environment for both choppers, an appropriate converter is selected and implemented in the present PV system. The chosen chopper is then modeled using the Simulink Power Systems toolbox and validates the design specifications. The simulated results of the complete PV system show that the performances of the PV panel using the improved two-stage MPPT algorithm provides better steady state and fast transient characteristics when compared with the conventional incremental conductance method. It yields not only a reduction in convergence time to track the maximum power point MPP, but also a significant reduction in power fluctuations around the MPP when subjected to slow and rapid solar irradiance changes.<br>Thesis (M.Sc.Eng)-University of KwaZulu-Natal, Durban, 2011.

碩士<br>國立彰化師範大學<br>電機工程學系<br>98<br>This paper proposed a high- power- factor wind energy maximum power point tracking system, which is composed of three “Single Phase Power-Controlled Power Factor Correctors(PFC)” and one “Maximum Power Point Tracking Controller(MPPTC)”. With PFC and MPPTC, the proposed system can increase the power factor in the circuit and obtain the maximum energy from the three-phase wind generator. Each “Single Phase Power-Controlled Power Factor Correctors” is composed of one single-phase rectifier, one full bridge converter, and one power factor corrector (PFC) IC UC3854; and “Maximum Power Point Tracking Controller” is implemented by one microchip “HT46R24” with maximum power point tracking (MPPT) algorithm. The proposed system has advantages that modulizes the system、increases the wind generator efficiency and decreases the noise of the wind generator. At last, the proposed system will be verified by implementation of a 600W prototype As experiment results, the proposed “high- power- factor wind energy maximum power point tracking system” not only reach a high power factor at 0.98, but also operate at the mpp under different wind velocity conditions, which improves the efficiency of the wind energy system effectively.

碩士<br>國立成功大學<br>電機工程學系<br>102<br>In recent years, permanent magnetic synchronous generator (PMSG) has been widely used in the wind power generation. A PMSG needs full-rated power converter to convert wind energy into electrical energy. Due to the increasing trend of power rating on the power converter; the power converter, however, usually operates at low wind speed. Paralleling PWM rectifiers to replace a full-rated power converter can reduce current stress of the converter and improve converter’s efficiency at low wind speed. However, paralleling PWM rectifiers may cause circulating current and distort the current waveform. In order to suppress circulating current, this thesis derives three phase rectifier model which includes generator, zero sequence impedance, and design a current controller accordingly. In addition, this research adopts a novel adaptive maximum power point tracking algorithm with current distribution strategy for the paralleling PWM rectifier. In contrast to traditional perturb and observe method, novel adaptive MPPT algorithm can be easily analyzed and determine wind change by feedback signal. The effectiveness of the circulating current suppression and maximum power tracking efficiency are verified by a wind turbine emulator.

碩士<br>國立宜蘭大學<br>電機工程學系碩士班<br>102<br>The purpose of this study is to develop solar energy control system with the functions of solar tracking and maximum power point tracking.Solar tracking system aims to track the position of the sun with the purposes of making the sun and solar panels form right-angled projection to obtain the maximization of solar energy. Solar tracking system designed in this study belongs to passive axis control system which means to control the dual-axis motor by means of longitude, latitude and time to calculate the angles of elevation and azimuth of the sun.The principles of maximum power point tracking are to adjust the duty cycle of the boost converter, aiming to change the output voltage and current of the solar cell to obtain the maximum power point. On literatures, the common maximum power point tracking method is incremental conductance.Proportion Integration Differentiation Like Fuzzy Control (PIDFC) was proposed in this research to improve the track efficiency of the maximum power point.Additionally, the conversion efficiency of the solar energy is susceptible to environmental temperature. Therefore, the temperature compensation mechanism was proposed with the purposes of adjusting dynamically the control command of the PIDFC and further achieving better power efficiency for the output power of the system. Finally, the differences between PIDFC maximum power point track control algorithm with the temperature compensation mechanism and the traditional MPPT as well as PID-MPPT were compared in this research. The results showed that system power, response time and stability were improved obviously.

碩士<br>國立高雄應用科技大學<br>電機工程系碩士班<br>95<br>The fossil fuels have been widely used to due the fast development of the industry, and it results in the problem of the exhaustion of fossil fuels and the damage of environment. The development of renewable energy sources will be the trend from the viewpoints of protecting environment and obtaining more energy sources. Wind power is one of the important renewable energy sources. If the wind energy can be used widely and effectively, the problems of energy demand, environment pollution and greenhouse effect can be relieved. Power converter interface is one of the key technologies for the wind power generator system, and the maximum power point tracking is one of the key technologies for power converter interface of the wind power generator system. In this thesis, a maximum power point tracking method for the permanent magnet synchronous wind power generator is proposed. A prototype is developed and tested to verify the performance of the proposed maximum power point tracking method. The experimental results show that the performance of proposed method can effectively track the maximum power of the permanent magnet synchronous wind power generator.

碩士<br>國立中正大學<br>電機工程研究所<br>107<br>This thesis applies the taguchi fractional order particle swarm optimization (TFPSO) with a 2kW series buck-boost converter and TI control circuit, which is self-developed and has functions of buck and boost, as the maximum power tracker (MPPT) of the solar photovoltaic system combine with solar power prediction. No matter under ideal environmental conditions or partial shading condition(PSC), the converter can operate at maximum power point. We train parameters to be the best for MPPT on computer simulation by using Taguchi method. To verify its performance, we conducted experiment base on single- peak power curve, double-peak power curve, triple-peak power curve, quadruple-peak power curve, insolation variations, and temperature variations. Results show that the proposed TFPSO has better performance then FPSO. Considering that 2kW polycrystalline solar photovoltaic panels are prone to aging problems, Therefore, the use of convolutional neural networks (CNN) for solar power prediction, and Compare and analyze the ideal power and predicted power. Keywords：Taguchi fractional order particle swarm optimization, CNN, MPPT

碩士<br>國立成功大學<br>航空太空工程學系碩博士班<br>97<br>Due to the energy crisis, renewable energy sources have been suggested as the possible solution. Among these sources, solar energy is pollution free and inexhaustible. Therefore it is a fairly good energy to generate electric power. However, the efficiency of solar cell is still very low, for that matter how to make the photovoltaic power system works in maximum power point is important. This thesis focuses on the maximum power point tracking control of photovoltaic power system. Owing to nonlinear I-V characteristics of photovoltaic cells, a maximum power point tracking algorithm is adopted to maximize the output power. In this thesis, An approach for maximum power point tracking using the sliding mode control is proposed. The proposed controller is robust to harsh environment changes and the performance of the controller is verified through simulations.

Photo voltaic installations in urban areas operate under uneven lighting conditions. For such a system to achieve its peak efficiency,each solar panel is connected in series through a micro-converter, a dc-dc converter that performs per-panel distributed maximum power point tracking (DMPPT). Normally solar panel have lower efficiency so to maximize the efficiency of PV cell we use MPPT controller, different technique are used to maximize power of PV cell like P & O Algorithm and Extremum seeking controller etc. The objective of this thesis is to design a compensator for the DMPPT micro-converter. And observe which one is batter in performance and reliable with speed and accuracy. The output power of PV cell in generally low to make useful we use a boost converter so that voltage level increase upto certain value. A novel, systematic approach to plant modelling is presented for this system, together with a framework for characterizing the plant’s uncertainty. Finally output of boost converter is apply in inverter and observe the output with both single phase inverter and three phase inverter with 180 degree conduction mode.and design of current mode PI controller for single phase PWM inverter. The controller is comprised of inductor current as the inner loop and voltage as outer feedback loop, to evaluate the performance of the designed controller objective of this thesis is to design a compensator for the DMPPT micro-converter. The simulation of all system give the result which justify the theoretical data.

碩士<br>中原大學<br>電機工程研究所<br>99<br>This report analyzes the differences of maximum power point tracking (MPPT) methods by using MATLAB simulations. Considering the small wind power system composed of a small wind turbine, permanent-magnet synchronous generator, three-phase full bridge rectifier, DC/DC converter, MPPT power controller, and load, we will find the problems for using traditional MPPT methods. Here the fuzzy logic control method as well as perturbation and observation method is utilized for the MPPT control under several cases with step, fixed, and variable speed wind. By the MATLAB simulation tests, the fuzzy logic control MPPT method is better than the perturbation and observation method.

碩士<br>中原大學<br>電機工程研究所<br>105<br>This thesis presents a power-slope-added incremental-conductance maximum power point tracking method (PS-INC MPPT) and the control method is realized by a photovoltaic buck converter. The PS-INC MPPT is carried out in two phases: incremental-conductance tracking (INC-tracking) is performed along with the I-V curve only in the INC zone; and the power-slope tracking (PS-tracking) is carried out on the PV curve to target the INC zone. The use of PS-INC MPPT method can eliminate the ambiguous incremental-conductance detection over the I-V curve of the left-hand side of the maximum power point (MPP), allowing the maximum power tracing to proceed smoothly. This technique retains the advantage of incremental-conductance tracking in the INC zone so that the MPP tracking can be achieved accurately and quickly. Finally, a 10 kW photovoltaic buck converter is demonstrated to realize the PS-INC MPPT method. Experimental results show that both the PS-tracking and the INC tracking are quick and accurate to meet the expected tracking theme.

碩士<br>國立中山大學<br>電機工程學系研究所<br>106<br>This thesis proposes a maximum power point tracking (MPPT) scheme with bidirectional partial power regulation for a solar power system with a number of photovoltaic (PV) panels connected in series. To operate all PV panels at their maximum power points (MPPs), each panel is attached by a bidirectional flyback converter to add or subtract an adequate current to the PV current to flow into an identical series current. As a result, only a part of power is processed by the associated converters, most power is directly supplied to the load from the series PV panels. With such a configuration, none of the PV panels will be short-circuited, and hence no drastic change will happen on the output voltage, even though they are under extensively different irradiances. The system maximum power can be realized by allocating the identical series current at a specific MPP, at which, the associated flyback converters need not be activated, and at the same time the total processed power via the flyback converters can be minimized. A laboratory system composed of three PV panels with the associated bidirectional flyback converters is set up. Experimental results have demonstrated the feasibility and effectiveness of the proposed MPPT scheme under various partially shaded cases.

碩士<br>國立中央大學<br>電機工程學系<br>107<br>This thesis mainly establishes a high-efficiency solar power conversion system, and cooperates with maximum power point tracking control and DC/DC boost converter with soft switching characteristics to improve the efficiency of the overall solar power generation system. The system proposed in this thesis is mainly divided into two parts. The first part is the discussion of the maximum power point tracking strategies. It analyzes the characteristics, advantages and disadvantages of various maximum power point tracking technologies. The second part is an investigation of DC/DC boost converter with soft switching characteristics to achieve maximum power point tracking and improve the input solar source to the voltage value required at the DC bus. Using zero-voltage switching technology, the voltage of the main circuit switch is first reduced to zero and then turned on to minimize the switching loss through the second auxiliary switch and the resonant circuit. The operation time of the second auxiliary switch is determined by the algorithm in the single chip to determine the best switching time. The soft-switching technology minimizes its switching loss, and combing the two parts to achieve a high-efficiency conversion system for the solar source.

碩士<br>國立聯合大學<br>電機工程學系碩士班<br>97<br>In this paper, we study the issue of maximum power tracking control in a wind power generation system. A fuzzy maximum power point tracking (Fuzzy MPPT) control with self-tuned scaling factor is proposed to improve the tracking response of the perturbation and observation (P&O) method. As applying P&O method in maximum power point tracking, a fast tracking would result in large oscillation around the operating point. Hence one has to make a compromise between the tracking speed and the stability of operating point. The proposed method provides a means to resolve this dilemma. In addition, in response to step change in the velocity of the wind, the proposed scheme also outperforms the P&O method. This feature makes the proposed wind power generation system being more applicable. In addition, only output voltage and current, without sensing the wind velocity, rotation speed and torque of the wind turbine, are required in implementing the proposed Fuzzy MPPT, which could reduce the cost and increase applicability in practice. The performance of the proposed Fuzzy MPPT is first verified by computer simulation with MATLAB/SIMULINK software. For experimental verification, a wind power generating system with utility parallel interface is built, in which an eZdsp F28335 development kit is employed to realize the three MPPT controllers: self-tuned and fixed scaling factor Fuzzy MPPT, and P&O method. The experimental results of these MPPT controllers are documented, and comparisons are made to illustrate the feasibility and superiority of our approach.

碩士<br>崑山科技大學<br>電機工程研究所<br>102<br>Since the solar cell output power is changed with the sunshine and temperature, the solar cell cannot work at the maximum power point at any time, which wastes a lot of power. This dissertation mainly studies a maximum power point tracking method of the solar power, which can track the maximum power output of the solar cell quickly and stable. Even when the weather changes quickly, the proposed method can achieve rapid and precise control of the largest solar power output. The fuzzy-neural network control method is used to realize the maximum power point tracking, which control program is implemented by a dsPIC30F40111 DSP. The voltage and current of solar cell are measured by the dsPIC30F40111 DSP. Then the maximum power point is calculated using the fuzzy-neural network controller, and output PWM signal to control DC-DC converter, which deliver the maximum power of the solar cell to a load to achieve maximum power point tracking control. Finally, experimental results demonstrate that the proposed method can quickly and effectively track to maximum power point of a solar power.

碩士<br>淡江大學<br>航空太空工程學系碩士班<br>103<br>This thesis presents the development of an integrated computer simulation program for solar power maximum power point tracking system. The simulation framework mainly con-sists of three major parts, a PV simulation model, dynamic model of the SEPIC/Zeta/Synchronous four-switch type buck-boost converters, and fuzzy logic based maximum power point tracking algorithms. The maximum power point is achieved by con-tinuously adjust the duty ratio command for the power converter. First, we integrate the PV model and dynamic model of the converter in pure computer program. The simulation re-sults demonstrate the solar power system is feasible by using pure MATLAB computer pro-gram. Perturb and observe method, incremental conductance method, and fuzzy logic based MPPT controllers are then integrated into the simulation program. Final MATLAB based graphic user interface is designed to facilitate understanding of the MPPT system. The sys-tem can be used for both engineering and education purposes.

碩士<br>國立中山大學<br>電機工程學系研究所<br>100<br>This thesis discusses the modeling of a micro-grid with photovoltaic (PV)-wind-fuel cell (FC) hybrid energy system and its operations. The system consists of the PV power, wind power, FC power, static var compensator (SVC) and an intelligent power controller. Wind and PV are primary power sources of the system, and an FC-electrolyzer combination is used as a backup and a long-term storage system. A simulation model for the micro-grid control of hybrid energy system has been developed using MATLAB/Simulink. A SVC was used to supply reactive power and regulate the voltage of the hybrid system. To achieve a fast and stable response for the real power control, the intelligent controller consists of a Radial Basis Function Network-Sliding Mode Control (RBFNSM) and a General Regression Neural Network (GRNN) for maximum power point tracking (MPPT). The pitch angle of wind turbine is controlled by RBFNSM, and the PV system uses GRNN, where the output signal is used to control the DC/DC boost converters to achieve the MPPT.

碩士<br>國立臺灣大學<br>電子工程學研究所<br>96<br>Batteries have been used in many applications in our life. However, batteries must be charged by chargers to maintain its electrical energy. Because solar energy is clean and inexhaustible energy, using solar charger is economy and environmental protection. The thesis describes the design of maximum power point tracker (MPP Tracker) for solar cell. The maximum power point tracker is used be a solar charger which charging maximum output power of solar cell to batteries. The MPP Tracker has simplified structure because only one current sensor is needed. So it suit to implement by analog circuit. The circuit reduced switching losses of power switch by zero voltage switching.

碩士<br>國立中興大學<br>電機工程學系所<br>98<br>In the global trend of energy saving and carbon emission reduction, the renewable energy development and greenhouse gas reduction have become one of the important issues for world electricity supply. Owing to the geometrical conditions of Taiwan, power generation using ocean current, solar and wind energy are the most promising. However, ocean current power generation technology has not been used effectively, while wind power applications are limited due to supply instability, environmental conditions and some high cost factors. In consideration of the natural environments and technology maturity under such conditions, solar photovoltaic power generation has been proven powerful in developing alternative energy. The purpose of this thesis is dedicated to develop maximum power point tracking (MPPT) controllers for solar photovoltaic cell arrays under no shading and under wind situations. After the development of the complete model of photovoltaic cells with the thermal dynamic model, such MPPT controllers are designed using sliding mode control method, gradient decent approach and fuzzy control logics. The effectiveness and merit of the proposed MPPT controllers are exemplified by conducting several simulations via Matlab/Simulink modeling.

博士<br>國立臺灣科技大學<br>電機工程系<br>103<br>In this dissertation, an asymmetrical fuzzy-logic-control (FLC) based maximum power point tracking (MPPT) algorithm for photovoltaic (PV) systems is presented. Two membership function (MF) design methodologies that can improve the effectiveness of the proposed asymmetrical FLC-based MPPT methods are then proposed. The first method can quickly determine the input MF setting values via the power–voltage (P–V) curve of solar cells under standard test conditions (STC). The second method uses the particle swarm optimization (PSO) technique to optimize the input MF setting values. Because the PSO approach must target a cost function and optimization, a cost function design methodology that meets the performance requirements of practical photovoltaic generation systems (PGSs) is also proposed. The proposed asymmetrical FLC-based MPPT algorithm is implemented using a low cost digital signal controller dsPIC33FJ16GS502. To validate the correctness and the effectiveness of the proposed method, a 300 W prototyping circuit is built and simulations as well as experiments are carried out accordingly. Compared with the symmetrical FLC-based MPPT method, the transient time and the MPPT tracking accuracy are improved by 25.8% and 0.93% under STC, respectively. Moreover, since the symmetrical FLC-based MPPT method fails to track the real MPP when irradiance level is low, the proposed asymmetrical FLC-based MPPT method can successfully deal with this problem. The advantages of the first MF design method are that it is simple and easy to adopt. The second MF design method applies the PSO technique to obtain the optimized input MF setting values. Compared with the first design method, the transient time and the MPP tracking accuracy can further be improved by 0.88% and 0.98%, respectively. This proves that PSO can be successfully applied to obtain the optimized MF setting values. In addition, the PSO optimized asymmetrical FLC-based MPPT method has the highest fitness value compared with other implemented methods.

碩士<br>遠東科技大學<br>電機工程研究所<br>103<br>This thesis proposes an intelligent control method implemented by FPGA chip for tracking the maximum power output of the wind turbine. Then store it in a battery which is charged by proposed charging program. From the computer simulation of Matlab/Simulink program to hardware circuit implementation to achieve the desired topic, maximum power point tracking (MPPT) and battery charging, The following hardware and software is completed. 1 Design a fuzzy controller to achieve DC voltage converter to track a reference voltage V_r by Matlab/Simpower tool to complete mathematical simulation analysis and to verify the effectiveness of the proposed controller. 2 Hall elements do not need to judge power change direction of wind turbine. Climbing method is used to adjust the PWM of the boost DC voltage converter to extract the maximum power output of the wind turbine. 3 To store different secondary battery load, the proposed Fuzzy control is used to adjust the output voltage of the DC voltage converter. 4 Integrating MPPT control, fuzzy control and battery charging control in an FPGA chip. 5 Completing constant current/voltage charging control.

碩士<br>中原大學<br>電機工程研究所<br>93<br>The wind-turbine generation system (WTGS) exhibits a nonlinear characteristic and thus its maximum power point varies with changing atmospheric conditions. In order to have the WTGS operate at maximum power points under different wind speeds, the thesis proposes two maximum-power-point-tracking (MPPT) control methods of the slope-comparing (SC) and the power-difference-product (PDP) algorithms to be used in the WTGS. In the thesis, load models of the WTGS under different wind speeds are first built up for design of control rules and feasibility studies of the proposed MPPT methods. Based on the traditional current-type perturbation & observation (P&O) as well as the three-point-weighting comparison (TPWC) algorithms, comparisons are made for the proposed SC and PDP methods. In the practical system implementations, the MPPT methods are integrated in the TMS320C240 digital signal processor (DSP) to adjust the duty ratios of the buck-boost converter to control the WTGS working with maximum power output. To compare and verify the effectiveness of the four MPPT control methods mentioned above, a practical WTGS has been used. The WTGS includes a small wind turbine with three 1.17m diameter blades and a three-phase, 12-pole, 100W, small permanent-magnet synchronous generator. The experimental results show that the proposed PDP controller achieves the best performance in terms of maximum power tracking capabilities among the four MPPT algorithms, though all the four MPPT algorithms can reach maximum power points in different wind-speed conditions.

碩士<br>國立高雄應用科技大學<br>電機工程系碩士班<br>95<br>The thesis presents a novel maximum power point tracking (MPPT) technique which is based on modulating pulse width signal to obtain maximum power point. The output power of photovoltaic (PV) cells is converted into AC power through a bi-direction energy converter and then directly parallel to power system. The proposed MPPT technique has a good tracking speed without destroying original operation condition when executing MPPT. Furthermore, the bi-direction energy converter is designed to convert the DC power generated by PV cells into AC power system, in which the dc bus voltage of the converter is controlled by the concept of energy balance. The result shows that it has a good performance. In this thesis the designed hardware is first given a detailed interpretation of its operation principle and is simulated by MATLAB and Pspice, respectively. Then, an analog circuit is designed to implement the proposed MPPT technique and a GAL with a digital signal processor having the capability of calculating output current by the energy balance equation is designed to implement the bi-direction energy converter. The experiment results verify the performance and feasibility of the proposed MPPT technique.

碩士<br>龍華科技大學<br>電機工程研究所<br>99<br>In recent centuries, the rise of industry and consciousness technology makes the Earth's surface temperature increasing, and causes serious climate changes and natural disasters. To avoid rapid depletion of energy resources and environmental deterioration, it is global trend and urgent priority to search for available clean energy sources. Since solar power technology has advantages of clean, inexhaustible and easy to acquire, it obtains more and more attention to the international and scientific community. The purpose of this paper is to compare three maximum power point tracking (MPPT) algorithms in a photovoltaic simulation system. The Matlab/Simulink is used in this paper to establish a model of photovoltaic system with MPPT function. This system is developed by combining the models of established solar module and DC-DC boost converter with the algorithms of perturbation and observation (P&O), incremental conductance (INC) and hill climbing (HC), respectively. The system will be simulated under different climate conditions and MPPT algorithms. According to the comparisons of the simulation results, it can be observed that the photovoltaic simulation system can track the maximum power accurately using the three MPPT algorithms discussed in this paper. HC MPPT algorithm possesses fast dynamic response, but P&O MPPT algorithm is well regulated PV output voltage and power than HC algorithm. Since the deterministic process of INC algorithm is more complicated than the other two algorithms, therefore, the tracking time spent by INC algorithm is also a little longer than the other two algorithms. The HC method is suitable for the cases of battery charging which doesn't need to care about the output stability, and the P&O method is more suitable for the system with sophisticated electric devices. Furthermore, the INC method is adaptable to the cases of fast changing weather conditions owing to its advantage of no misjudgment.

碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>102<br>The thesis aims to design a maximum photovoltaic power point tracking circuit. The basic concept of the proposed maximum power point tracking technique is based on approximating the characteristic curve of the photovoltaic power output by piecewise quadratic curves. At each step, the apex of the piecewise polynomial is used to be the next operation duty cycle so that the operation point can rapidly move to the maximum power point. To verify the feasibility of the proposed maximum power point tracking technique, we first implement an analog solar cell circuit which is used for simulating the maximum power point tracking experiments. Before to do this, each part of the circuit is simulated and analyzed by the relative software to testify its compliance with the output characteristics of solar cells. Based on the impedance matching for the overall tracking circuit, the equivalent input impedance of the solar cell is adjusted by controller to match the load impedance of the solar cell so that the operating point of the solar cell is moved to the maximum power point and the solar cell works at the maximum power point.

One of the most important challenges for researchers is to generate energy from fresh, resourceful & environmentally pleasant sources. While greenhouse emissions are reduced, more attention is attracted towards solar system because it offers great chance to produce electricity among all renewable energy sources. In spite of all advantages of solar power systems, they do not show advantageous efficiency. Insolation, Temperature, spectral characteristics of sunlight, shadow, dirt & etc. are the factors, on which efficiency of solar cell depends up on. The output power of photovoltaic (PV) array reduces with the changes in irradiance on panels due to rapid climate changes for example increase in temperature and cloudy weather. It can also be said as, according to operational and environmental conditions, each PV cell produces an energy. From the poor efficiency point of view some procedures are given, from which a concept called as “Maximum Power Point Tracking” (MPPT). The goal of all MPPT methods are identical to improving the output power of PV array in every condition by tracking the maximum power. Solar cells have non-linear i-v characteristics. By the series connection of PV cell, output voltage of PV panel increases. Similarly, by the parallel connection of PV cell output current of PV array increases. Many MPPT algorithms are there to track maximum power point such as perturb and observe (P&O), incremental conductance, constant voltage, constant current and parasitic capacitance algorithm etc. Perturb and observe algorithm is a simple algorithm but it tracks wrong direction with the sudden change in weather and it oscillates about the MPP (Maximum power point), which can be eliminated by using incremental conductance algorithm. Under partial shadow condition, P-V (power-voltage) characteristic curve is having multiple peaks. At that time, it is difficult task to track actual maximum power point.

碩士<br>崑山科技大學<br>電機工程研究所<br>97<br>This work implements a solar power battery energy storage system（BESS）with maximum power point tracking（MPPT）under substantial variation in temperature and intensity of illumination. The tracker was designed using the perturbation and observation method to track rapidly the maximum power point of the energy output of the solar cells. The power generation data were transmitted to computers via RS232 for analysis and a battery charger was realized using a dsPIC30F chip. The maximum power was output following photovoltaic transformation under varying intensity of illumination and the power generated by the solar cells was fed back to the lead-acid battery to supply the load.

碩士<br>國立勤益科技大學<br>電機工程系<br>101<br>The main purpose of this thesis is to propose a maximum power point tracking (MPPT) algorithm for photovoltaic (PV) module array under considering the module shadow and fault. The proposed maximum power point tracking method is based on a modified particle swarm optimization (PSO) method to reach the real maximum power point (MPP) with multi-peak power-voltage (P-V) output curve for PV module array under considering the module shadow and fault. At first, Solar Pro software is used to capture the parameters of open-circuit voltage and short-circuit current for PV module array under different shadow conditions according to the HIP 2717 PV module. Accordingly, a module simulator circuit is made to implement the shadow conditions for PV module array under module shadow or fault. In addition, Pspice is used to pick up some simulation cases of 2-peaks, 3-peaks and 4-peaks of P-V curve under module shadow or fault for Matlab simulations to compare the MPPT performance between traditional PSO and modified PSO algorithms. As the simulation result, modified PSO algorithm performs performance well than the traditional PSO. Finally, a PIC microcontroller was adopted to implement the traditional PSO and modified PSO algorithm to carry out the MPPT with the multi-peak cases of P-V curve for the PV module array under module shadow or fault. The experimental results also verify that the modified PSO algorithm posses better tracking response and accuracy than traditional PSO method.