Rozprawy doktorskie na temat „Maximum Power Point Technique”

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.

Orientador: Dilson Amancio Alves
Banca: Sergio Azevedo de Oliveira
Banca: Francisco Carlos Vieira Malange
Banca: Luiz Carlos Pereira da Silva
Banca: Madson Cortes de Almeida
Resumo: Este trabalho analisa a utilização de técnicas de parametrização global para o fluxo de carga continuado. Essas técnicas são consideradas inadequadas para a obtenção da margem de carregamento de sistemas com problemas de estabilidade de tensão com características fortemente locais. Isto se deve ao fato de que no ponto de máximo carregamento a singularidade da matriz Jacobiana do método de parametrização global coincide com a da matriz Jacobiana do fluxo de carga. Nesses casos, a parametrização local é considerada como a única forma de se eliminar a singularidade. Entretanto, este trabalho mostra que a singularidade também pode ser eficientemente eliminada não só para estes sistemas, mas para qualquer outro, através de uma nova técnica de parametrização (global). A técnica utiliza a equação de uma reta que passa por um ponto no plano determinado pelas variáveis fator de carregamento e a somatória das magnitudes, ou dos ângulos, das tensões nodais de todas as barras do sistema, que são as variáveis comumente usadas pelas técnicas de parametrização global. Os resultados obtidos para diversos sistemas confirmam o aumento da eficiência dos métodos propostos e mostram sua viabilidade para aplicações no planejamento da operação nos atuais sistemas de gerenciamento de energia
Abstract: This work presents an analysis of the use of global parameterization techniques to the continuation power flow. Those techniques are considered inadequate for computation of the loading margin of power systems characterized by strong local static voltage stability. In such systems, at maximum loading point, the singularity of the Jacobian matrices of global parameterization techniques coincide with the one of the power flow Jacobian matrix. In those cases, the local parameterization is considered as the only way to overcome the singularity. However, this paper shows that this kind of singularity can be efficiently eliminated not only for these systems, but also for all others, by a new parameterization technique (global). This technique uses the addition of a line equation, which passes through a point in the plane determined by the sum of all the bus voltage magnitudes, or angles, and loading factor variables, that are variables commonly used by global parameterization techniques. The obtained results for several systems confirm the efficiency increased of the proposed methods and show its viability for applications in the operating planning in a modern energy management system
Doutor

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.

Abstract This thesis presents measuring techniques as well as measured and simulated results with the aim of helping the design of photovoltaic energy harvesting systems. Therefore, cost-effective measurement setups were developed for collecting the amount of irradiation, for both stationary and moving photovoltaic (PV) installations. The impact of the time resolution of solar radiation data on estimating the available solar energy was investigated. For moving PV installations, the dynamics and the rate of changes in the available irradiation were studied in order to analyse the effects on maximum power point tracking (MPPT) algorithms. In addition, possibilities for harvesting PV energy in indoor environments were also investigated. The main contribution of this thesis is the effective testing of PV cells and complete PV panels: instead of measuring the characteristic I-V (Current-Voltage) response under strictly controlled artificial illumination, photovoltaics are simply biased externally. Then, with the help of synchronized thermography (ST), infrared (IR) images of the PV panel self-heating are recorded. In the obtained IR-images, defected areas are seen as cold spots, since they are not biased by the external power supply. From the calculated temperature variations, the size of the defect area can be calculated and, thus, the loss in output power can be estimated. The method is shown to work both with and without glass encapsulation
Tiivistelmä Tämä työ esittelee mittaustekniikoita ja mitattuja ja simuloituja tuloksia aurinkoenergian keruujärjestelmien suunnittelun avuksi. Työtä varten kehitettiin kustannustehokas mittausjärjestelmä, jonka avulla arvioitiin aurinkoenergian määrää sekä stationaarisen että liikkuvan valokennon tapauksissa. Näiden lisäksi tutkittiin mittaustaajuuden vaikutusta arvioitaessa saatavilla olevan aurinkoenergian määrää. Liikkuvan PV (photovoltaic)-asennuksen avulla tutkittiin saatavilla olevan aurinkoenergian vaihtelun suuruutta ja nopeutta tarkoituksena analysoida näiden vaikutuksia käytettäviin MPPT-algoritmeihin. Tämä lisäksi tutkittiin myös valoenergian keruumahdollisuuksia sisätiloissa. Työn tärkein kontribuutio on valokennojen ja kokonaisten valopaneelien toiminnallisuuden testaamisen tehostaminen. Tyypillisesti PV:n toiminnallisuus varmistetaan tarkasti määritetyssä ympäristössä suoritetun I-V -ominaiskäyrämittauksen avulla. Tämän työn menetelmä on yksinkertaisesti biasoida PV:t ulkoisesti, minkä jälkeen ST (synchronized thermpgraphy) -kuvauksen avulla määritetään PV-paneelien itselämpenemistä kuvaavat infrapunakuvat. Paneelin vioittuneet alueet erottuvat IR-kuvissa kylminä alueina ulkoisen biasoinnin puuttuessa. IR-kuvista havaituista lämpötilavaihteluista on mahdollista määrittää vioittuneen alueen koko ja siten arvioida myös menetettyä lähtötehoa. Kyseisen metodin toimivuus osoitettiin niin lasikoteloiduilla kuin ilman sitä olevilla PV-paneeleilla

Orientador: Dilson Amâncio Alves
Banca: Anna Diva Plasencia Lotufo
Banca: Edmárcio Antonio Belati
Resumo: Este trabalho apresenta o método de Newton desacoplado para o fluxo de carga continuado. O método foi melhorado por uma técnica de parametrização geométrica possibilitando assim o traçado completo das curvas P-V, e o cálculo do ponto de máximo carregamento de sistemas elétricos de potência, sem os problemas de mau condicionamento. O objetivo é o de apresentar de forma didática os passos envolvidos no processo de melhoria do método de Newton Desacoplado a partir da observação das trajetórias de solução do fluxo de carga. A técnica de parametrização geométrica que consiste na adição de uma equação de reta que passa por um ponto no plano formado pelas variáveis: tensão nodal de uma barra k qualquer e o fator de carregamento eliminam os problemas de singularidades das matrizes envolvidas no processo e ampliam o grupo das variáveis de tensão que podem ser usadas como parâmetro da continuação. Os resultados obtidos com a nova metodologia para o sistema teste do IEEE (14, 30, 57, 118 e 300 barras) e também para os sistemas reais de grande porte, o 638 barras do sistema Sul-Sudeste brasileiro e do sistema de 904 barras do sudoeste Americano, mostram que as características do método convencional são melhoradas na região do ponto de máximo carregamento e que a região de convergência ao redor da singularidade é sensivelmente aumentada. São apresentados vários testes com a finalidade de prover um completo entendimento do funcionamento do método proposto e também avaliar seu desempenho
Abstract: This work presents the decoupled Newton method for continuation power flow. The method was improved by using a geometric parameterization technique that allows the complete tracing of P-V curves, and the computation of maximum loading point of a power system, without ill-conditioning problems. The goal is to present in a clear and didactic way the steps involved in the development of the improved decoupled Newton method obtained from the observation of the geometrical behavior of power flow solutions. The geometric parameterization technique that consists of the addition of a line equation, which passes through a point in the plane determined by the bus voltage magnitude and loading factor variables, can eliminate the ill-conditioning problems of matrices used by the method and can enlarge the set of voltage variables that can be used as continuation parameter to P-V curve tracing. The method is applied to the IEEE systems (14, 30, 57, 118 and 300 buses) and two large real systems: the south-southeast Brazilian system (638 buses) and the 904-bus southwestern American system. The results show that the best characteristics of the conventional decoupled Newton's method are improved in the vicinity of the maximum loading point and therefore the region of convergence around it is enlarged. Several tests are presented with the purpose of providing a complete understanding of the behavior of the proposed method and also to evaluate its performance
Mestre

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Este trabalho apresenta o método de Newton desacoplado para o fluxo de carga continuado. O método foi melhorado por uma técnica de parametrização geométrica possibilitando assim o traçado completo das curvas P-V, e o cálculo do ponto de máximo carregamento de sistemas elétricos de potência, sem os problemas de mau condicionamento. O objetivo é o de apresentar de forma didática os passos envolvidos no processo de melhoria do método de Newton Desacoplado a partir da observação das trajetórias de solução do fluxo de carga. A técnica de parametrização geométrica que consiste na adição de uma equação de reta que passa por um ponto no plano formado pelas variáveis: tensão nodal de uma barra k qualquer e o fator de carregamento eliminam os problemas de singularidades das matrizes envolvidas no processo e ampliam o grupo das variáveis de tensão que podem ser usadas como parâmetro da continuação. Os resultados obtidos com a nova metodologia para o sistema teste do IEEE (14, 30, 57, 118 e 300 barras) e também para os sistemas reais de grande porte, o 638 barras do sistema Sul-Sudeste brasileiro e do sistema de 904 barras do sudoeste Americano, mostram que as características do método convencional são melhoradas na região do ponto de máximo carregamento e que a região de convergência ao redor da singularidade é sensivelmente aumentada. São apresentados vários testes com a finalidade de prover um completo entendimento do funcionamento do método proposto e também avaliar seu desempenho
This work presents the decoupled Newton method for continuation power flow. The method was improved by using a geometric parameterization technique that allows the complete tracing of P-V curves, and the computation of maximum loading point of a power system, without ill-conditioning problems. The goal is to present in a clear and didactic way the steps involved in the development of the improved decoupled Newton method obtained from the observation of the geometrical behavior of power flow solutions. The geometric parameterization technique that consists of the addition of a line equation, which passes through a point in the plane determined by the bus voltage magnitude and loading factor variables, can eliminate the ill-conditioning problems of matrices used by the method and can enlarge the set of voltage variables that can be used as continuation parameter to P-V curve tracing. The method is applied to the IEEE systems (14, 30, 57, 118 and 300 buses) and two large real systems: the south-southeast Brazilian system (638 buses) and the 904-bus southwestern American system. The results show that the best characteristics of the conventional decoupled Newton’s method are improved in the vicinity of the maximum loading point and therefore the region of convergence around it is enlarged. Several tests are presented with the purpose of providing a complete understanding of the behavior of the proposed method and also to evaluate its performance

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Este trabalho analisa a utilização de técnicas de parametrização global para o fluxo de carga continuado. Essas técnicas são consideradas inadequadas para a obtenção da margem de carregamento de sistemas com problemas de estabilidade de tensão com características fortemente locais. Isto se deve ao fato de que no ponto de máximo carregamento a singularidade da matriz Jacobiana do método de parametrização global coincide com a da matriz Jacobiana do fluxo de carga. Nesses casos, a parametrização local é considerada como a única forma de se eliminar a singularidade. Entretanto, este trabalho mostra que a singularidade também pode ser eficientemente eliminada não só para estes sistemas, mas para qualquer outro, através de uma nova técnica de parametrização (global). A técnica utiliza a equação de uma reta que passa por um ponto no plano determinado pelas variáveis fator de carregamento e a somatória das magnitudes, ou dos ângulos, das tensões nodais de todas as barras do sistema, que são as variáveis comumente usadas pelas técnicas de parametrização global. Os resultados obtidos para diversos sistemas confirmam o aumento da eficiência dos métodos propostos e mostram sua viabilidade para aplicações no planejamento da operação nos atuais sistemas de gerenciamento de energia
This work presents an analysis of the use of global parameterization techniques to the continuation power flow. Those techniques are considered inadequate for computation of the loading margin of power systems characterized by strong local static voltage stability. In such systems, at maximum loading point, the singularity of the Jacobian matrices of global parameterization techniques coincide with the one of the power flow Jacobian matrix. In those cases, the local parameterization is considered as the only way to overcome the singularity. However, this paper shows that this kind of singularity can be efficiently eliminated not only for these systems, but also for all others, by a new parameterization technique (global). This technique uses the addition of a line equation, which passes through a point in the plane determined by the sum of all the bus voltage magnitudes, or angles, and loading factor variables, that are variables commonly used by global parameterization techniques. The obtained results for several systems confirm the efficiency increased of the proposed methods and show its viability for applications in the operating planning in a modern energy management system

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

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.

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.

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

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

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

Maximum Power Point Tracking (MPPT) strategies in Photovoltaic (PV) systems ensure efficient utilization of PV arrays. Among different strategies, the Perturb and Observe (P&O) algorithm has gained wide popularity due to its intuitive nature and simple implementation. However, such simplicity in P&O introduces two inherent issues, an artificial perturbation that creates losses in steady-state operation and a limited ability to track transients in changing environmental conditions. This work develops and discusses in detail an MPPT algorithm with zero oscillation and slope tracking to address those technical challenges. The strategy combines three techniques to improve steady-state behavior and transient operation: 1) idle operation on the Maximum Power Point (MPP), 2) identification of the irradiance change through a natural perturbation and 3) a simple multi-level adaptive tracking step. Two key elements, which form the foundation of the proposed solution, are investigated: the suppression of the artificial perturbation at the MPP and the indirect identification of irradiance change through a current-monitoring algorithm which acts as a natural perturbation. The Zero-oscillation, Adaptive step Perturb and Observe (ZA-P&O) MPPT strategy builds on these mechanisms to identify relevant information and produce efficiency gains. As a result, the combined techniques achieve superior overall performance while maintaining simplicity of implementation. Simulations and experimental results are provided to validate the proposed strategy and illustrate its behavior in steady state and transient operation.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate

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.
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%.

It is essential to always track maximum power from photovoltaic (PV) sources. Failure to track the global maximum power point under partial shading conditions is one of the major reasons that lead to significant power losses. Several maximum power point tracking methods have been proposed to deal with this problem. However, none of them were able to effectively identify the occurrence of partial shading. With the facility of Matlab modelling and simulation as well as the aid of a constructed solar emulator, the power-voltage characteristics of a PV panel under uniform and non-uniform irradiance conditions have been studied and some useful conclusions have been identified from observation. Based on these conclusions, a novel maximum power point tracking algorithm has been proposed, which is capable of identifying the occurrence of partial shading hence determining the need for a global scan over the operation range of PV panels for the true maximum power point. In the meantime, the effect of PV dynamics, due to the capacitance of PV cells, on maximum power point trackers has been investigated and some initial results and suggestions have been presented in this work.

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.
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.

碩士
國立高雄應用科技大學
電機工程系碩士班
95
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
國立成功大學
系統及船舶機電工程學系碩博士班
97
Solar-energy-auxiliary-power ship includes solar array system and energy storage system. For better use of the photovoltaic effect of the solar cell, this work takes advantage of the newly developed Maximum Power Point Tracking (MPPT) technique for the solar array system to maximize the power generated by the PV array, and to store the energy in the battery. In the proposed MPPT system, we improved the circuitry, and used the quadratic maximization method combining with PWM duty cycle adjustment to calculate the maximum power point. The use of Solar Array Simulator (SAS) has proven the proposed MPPT method is faster than other methods to track the maximum power point. By implementing the proposed MPPT technique with the energy storage system, we also build a solar-energy-auxiliary-power ship. The testing results will be also reported. Key words: solar cell, photovoltaic effect, MPPT, quadratic method,energy stored system, Solar Array Simulator.

碩士
國立臺灣科技大學
電機工程系
107
Photovoltaic generation systems (PGSs) frequently experience partial shading conditions (PSCs). Because PSCs will result in multiple peak values on the power-to-voltage characteristic curve, developing an algorithm that facilitates tracking global maximum power point (GMPP) is crucial. Therefore, a two-stage GMPP tracking algorithm is proposed in this thesis. In the first stage, the vicinity of the maximum power point is obtained by performing extensive simulations, while during the second stage, alpha factor perturb and observe (P&O) method is utilized to improve the tracking accuracy and stably control the operating point at the maximum power point. To verify the correctness and feasibility of the proposed MPPT algorithm, a 600 W prototyping circuit is constructed. The simulation results compared with the deterministic cuckoo search (CS) method under partial shading conditions show that the rising time is shortened by 34.67%, the settling time is improved by 25.18%, the average tracking power loss is reduced by 35.68%, and the 99.99% steady-state tracking accuracy can be achieved. Experimental results also validate that the proposed method can obtain GMPP under different shading patterns, and above 99.00% steady-state tracking accuracy has been reached on the specific five PSC test cases.

碩士
國立中山大學
電機工程學系研究所
104
ABSTRACT Maximum Power Point Tracking (MPPT) plays an important role in Photovoltaic Generation (PVG) systems because it maximizes the power output from a PVG system. Thus, an MPPT can minimize the overall system cost. MPPT operates a PVG system under different solar irradiances and temperatures. Many such algorithms have been proposed. This thesis provides a comparison between Perturb and Observe (P&O) method, and Particle Swarm Optimization (PSO) method with the weather data from Taiwan Weather Bureau. Matrix Laboratory (MATLAB) programming by using real data is implemented for a PVG system with a rated output of 200 W energy to obtain the curve performance and the unharvest energy for different the MPPT algorithms.

碩士
國立臺灣科技大學
電機工程系
107
The solar panel is becoming an increasingly popular form of renewable energy due to its decreasing installation costs and environmental friendliness. When the photovoltaic generation system (PGS) is installed in an area where the insolation changes rapidly, the maximum power point tracking (MPPT) technique is the key to make full use of the solar energy. This thesis implements the PI controlled perturb and observe (P&O) MPPT algorithm in order to solve the trade-off problem between the tracking speed and the steady state tracking accuracy of the traditional fixed-step P&O method. Compared to the traditional fixed-step P&O method and the variable step P&O method, the PI controlled P&O method can improve the tracking speed of the solar system by 58% and 55.8%, respectively. Moreover, the power loss of the solar system can be reduced by 44.8% and 37.2%, respectively. In addition, the effects of the tunable parameters – KP and KI – are also discussed in this thesis to facilitate the design of the realized PI controlled perturb and observe maximum power point tracking algorithm.

碩士
國立暨南國際大學
電機工程學系
104
The major target of this thesis is to develop the maximum power tracker of photovoltaic (PV) systems under the partial-shading conditions. Since the weather is unpredictable, there might exist local and global maximum power points (MPP) in the systems. Therefore, we must be able to track the global MPP under the partial-shading conditions in order to make our PV systems offer effective maximum power output for obtaining optimal system performance. First of all, the mathematical model is established for a PV array system to investigate and analyze the voltage and power output under partial-shade and non-partial-shade conditioning. However, the output power of PV systems could have various MPP under partial-shading conditions, so we have to determine an appropriate technology for the tracking control of global MPP. A novel concept is presented to modify the traditional particle swarm optimization method for strengthening algorithm capability and improving the system performance. In addition to using linear decreasing inertia weight, we apply nonlinear adapting learning factors for enhancing the tracking ability. It can avoid falling into local maximum solutions and provide the system to have more accurate convergence. As a result, the simulation results show that the modified particle swarm optimization has the potentials to track the global MPP with accurate rate of convergence under partial-shading conditions.

碩士
長庚大學
電機工程學系
99
In this thesis, we proposed a new folded photovoltaic maximum power point tracking circuit based on schedule reordering technique and look-ahead restoring divider, which can effectively reduce power consumption and hardware cost. Our photovoltaic maximum power point tracking algorithm is based on gain-adaptive perturb-and-observe method. It can perform with higher power conversion efficiency and response faster as weather changes and also solve the periodic disturbance problem in the traditional perturb-and-observe algorithm. With our proposed schedule reordering technique, we can solve the signal synchronization problem existing in the interface between folded maximum power point tracking circuit and photovoltaic power conversion system by adjusting folding factor and signal processing order. Through our proposed retiming and path balancing technique, we can balance the whole circuit loading to further lower power consumption in the folded maximum power point tracking circuit. With our proposed look-ahead restoring divider design, we can reduce the hardware complexity and the carry ripple switching chance in the divider. Since divider is the most complex circuit in the gain-adaptive perturb-and-observe algorithm, improvement in the divider can lower both hardware cost and power consumption in the photovoltaic power conversion system. As compared with the conventional folded photovoltaic maximum power point circuit design, we can save 40.37% transistor count and lower 78.37% power consumption while maintain the same power conversion efficiency of 97.9%. To make the whole system can be used with low-voltage solar cells, we implemented our chip in TSMC 90nmCMOS process with chip area of 1199um*679um.

碩士
國立臺灣科技大學
電子工程系
96
Due to gradual shortage of fossil fuel, alternative energy such as solar energy has recently received global awareness, and businesses relevant to the application of it have become more and more prosperous. Based on the fact, this thesis intends to develop a solar cell-driven, high performance converter with the help of a digital signal processor (DSP) to implement Maximum Power Point Tracking (MPPT), satisfy the characteristics demand of Lead-acid battery charging, and fulfill parallel operation of multiple modules. First of all, this thesis adopts a boost converter as the main topology and individually apply three different methods of current sensing, Hall sensor, resistor and Rds(on), to the converter to see which one works best for MPPT. Another SEPIC converter would be built for comparison of MPPT performance. Furthermore, perturbation and observation method which is widely used in industry is chosen as the algorithm of MPPT and is implemented with one of the TMS320X280X family of microprocessors to examine the MPPT performance of the converter. Afterwards, a pulse charging method is combined to charge lead-acid battery. Finally, three boost converters were parallel-connected through a Master-Slave line topology and digitally controlled by three interleaved pulse-width-modulation signals which are generated by a simple control method to do battery charging. Therefore, for ease of market development, using parallel operation of multiple modules can raise the convenience and expansion of application in terms of different types of solar cells and batteries. Keywords: MPPT, pulse charging, interleave

碩士
國立臺灣科技大學
電機工程系
105
When partial shading conditions occur, the P-V characteristics curves of the photovoltaic string may exhibit multiple peaks and the operating point may not be at the global maximum power (GMP) point, leading to low efficiency. Therefore, maximum power point tracking (MPPT) control strategy is needed in a photovoltaic system to output the power at the maximum. Combing two different MPPT strategies has gained its popularity because strategies in complementary can improve the performance of a single algorithm. This thesis proposes a hybrid method, combing improved firefly algorithm (IFA) and particle swarm optimization (PSO) to capture the great attributes from both methods, and yield a better MPPT control strategy. In order to justify the proposed method, we compared it with same of the state of the art such as Multiple Perturb-and-Observe, Perturb-and-Observe+Particle Swarm Optimization, Different Evolution+ Particle Swarm Optimization and PSO. All the verifications were done experimentally and the results showed that the proposed hybrid method yields the highest efficiency and the shortest tracking time.

碩士
國立勤益科技大學
電機工程系
100
In the photovoltaic systems, a maximum power point tracking (MPPT) controller is employed in such a way that the output power provided by a photovoltaic (PV) system is boosted to its maximum level. However, in the context of abrupt changes in irradiance, conventional MPPT controller approaches suffer from insufficient robustness against ambient variation, inferior transient response and a loss of output power as a consequence of the long duration required of tracking procedures. Accordingly, in this work the maximum power point tracking is carried out successfully using a sliding mode extremum-seeking control (SMESC) method. In addition, this paper compared three controller tracking performances included extremum seeking control, sinusoidal extremum seeking control and sliding mode extremum seeking control by simulations and experiments. These three methods also show to track the maximum power point promptly in the case of an abrupt change in irradiance. The simulation and experimental results show that the SMESC approach has better transient and steady state responses under the rapid change in the atmospheric environment. An excellent robustness along with system stability is also demonstrated as well.

碩士
聖約翰科技大學
電機工程系碩士在職專班
104
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.
Thesis (M.Sc.Eng)-University of KwaZulu-Natal, Durban, 2011.

碩士
國立彰化師範大學
電機工程學系
98
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
國立成功大學
電機工程學系
102
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
國立中正大學
電機工程所
96
The main objective of this thesis is to design and implement a modular maximum power point tracker (MPPT). Due to each MPPT module only supplying partial load current, the current stress of switching components can be reduced relatively. In addition, when one of modules fails, the rest of modules can still continuously supply load current to keep the system normally operated. Each MPPT module mainly contains two parts, the MPPT control circuit and the master-slave control circuit. The MPPT control circuit uses "Perturb and Observe" technique to track the maximum power point of the solar cell array. The master-slave control circuit detects the magnitude of currents flowing through modules. The module which has the highest current would be assigned as the master module, performing MPPT control. The other slave modules adjust the current flow through themselves to achieve current distribution between each module. Simulated results and experimental results will be presented to verify the validity of the proposed circuit.

碩士
國立高雄應用科技大學
電機工程系碩士班
95
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
國立中正大學
電機工程研究所
107
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
國立臺灣大學
電子工程學研究所
99
Batteries have been used in many applications in our life. Nevertheless, batteries must be charged by chargers to maintain their electrical energy. There are many different chargers in the market. Because solar energy is clean and inexhaustible, using solar charger is economical and environment friendly. Traditionally, the maximum power point tracker is implemented by a digital microprocessor for high power applications and high cost. However, they are not applied to low-power applications, such as portable electronic devices. Therefore, we attempt to do a research for a maximum power point tracker that can be applied to low-power application and has low cost. The maximum power point tracker is used as a solar charger charging output power from solar cells to batteries. Besides, the MPP tracker is also modified. The MPP tracker has a simplified structure, because only one multiplier is needed. The circuit is implemented by analog design and it has excellent tracking effectiveness. Finally, an experimental circuit is implemented to verify the results. In addition, the thesis compares with the MPP tracker without modification and the modified MPP tracker.

碩士
國立成功大學
航空太空工程學系碩博士班
97
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.

碩士
國立中正大學
電機工程所
97
This thesis presents design and implementation of a maximum power point tracker (MPPT) with soft switching feature. The converter topology is a boost converter with a turn-on and turn-off passive lossless snubber (one inductor, two capacitors, and three diodes). The MPPT controller is based on a “perturb and observe” algorithm to track maximum power points of PV panels. At first, the types and characteristics of PV panels are introduced, and then, the boost converter and snubber are analyzed. A 4.8 kW MPPT has been implemented to verify its performance, which achieves the highest conversion efficiency of 97%.

碩士
國立高雄應用科技大學
電機工程系博碩士班
96
The thesis investigates the cost analysis of a kind of photovoltaic maximum power point trackers (MPPT) which is based on using the pulse width modulation (PWM) signal as perturb sources. The advantage of such tracker has a good tracking speed without destroying original operation condition when executing maximum power point tracking. However, each of photovoltaic cells shall install a MPPT to insure each photovoltaic cell is operated at maximum power point at the cost of MPPT. In order to make cost analysis, three different groups of photovoltaic cells are subjected into a MPPT and their maximum power efficiencies are discussed. The MATLAB simulation results show two groups of photovoltaic cells subjected into a MPPT provides a lower cost without sacrificing its efficiency.

碩士
中原大學
電機工程研究所
99
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
中原大學
電機工程研究所
105
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
國立中山大學
電機工程學系研究所
106
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
國立中央大學
電機工程學系
107
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.

博士
國立臺灣科技大學
電機工程系
104
Due to the escalating energy costs and the depletion of fossil fuel sources, the search for cleaner and environmental friendly energy becomes increasingly urgent. These growing global issues force public to seek for alternative methods of generating electrical power. Among the feasible technologies for this purpose, thermoelectric (TE) energy converter is gradually earning interest because of its ability to transform heat given out from the transportation or industrial sectors into electricity. Thermoelectric generator (TEG) is an energy conversion technology which allows thermal energy directly converting into electrical energy and vice versa. TEG modules are flexible and thus can be utilized in systems from the miniature Milliwatt level to large-scale Kilowatt applications. Advantages of TEG include free maintenance, silent operation, eco-friendliness and high reliability. Furthermore, TEG is capable of generating electricity continuously as long as there are a heat source and a cold source. In this dissertation, a novel hybrid maximum power point tracking (MPPT) method suitable for TEG system is proposed and investigated. The proposed MPPT technique combines the simplicity of perturb and observe (P&O) method and the fast tracking ability of open circuit voltage (OCV) method. The advantages of the proposed MPPT approach include fast tracking speed, no additional circuit required and no temporary power loss. To validate the feasibility of the proposed MPPT technique, an 1.2 kW thermoelectric generation system for industrial waste heat recovery is also constructed, experimental results show that comparing with conventional P&O technique, the proposed method can improve the tracking speed for 42.9% and 86.2% when temperature differences are ΔT=60°C and ΔT=180°C, respectively. Moreover, the energy loss can be improved by 24.0% and 87.0% when temperature differences are ΔT=60°C and ΔT=180°C, respectively.

碩士
國立中正大學
電機工程研究所
101
This thesis presents development of high efficiency multiple maximum power point trackers (MPPTs) for PV panels in DC micro-grid and charge/discharge system. To deal with wide output voltage range of the PV panels, the proposed MPPT topology consists of buck and boost converters. When input voltage changes between high voltage and low voltage, the mechanism of changing reference input voltage is adopted to switch the operation mode. For increasing the efficiency of PV panels, a perturbation and observation algorithm is employed to track the maximum output power of the panels. Moreover, the multiple maximum power point trackers can be operated in independent mode or in parallel mode. In the parallel mode, a current balancing control is adopted for the multiple MPPT modules. In addition, the multiple MPPT modules are designed with a hot-swap feature to increase the application feasibility of the multiple MPPT modules in the DC micro-grid or charge/discharge systems. Finally experimental results have shown that the conversion efficiency can reach 98 % and the maximum power tracking accuracy can reach 99 %.