This thesis focuses on the single-phase voltage-source inverter for use in photovoltaic (PV) electricity generating systems in both stand-alone and grid-tied applications. In many cases, developments in single-phase PV systems have followed developments in three-phase systems. Time-variant systems are more difficult to control than time-invariant systems. Nevertheless, by using suitable transformation techniques, time-variant systems can often be modelled as time-invariant systems. After the transformation, the control signals that are usually time-variant (often varying sinusoidally in time) become time-invariant at the fundamental frequency, and are hence much easier to deal with. With this approach, synchronous rotating frame control techniques have been previously proposed for high performance three-phase inverter applications. The transformation theory cannot be applied directly in single-phase systems without modification, and the d-q components would not be time-invariant in situations where harmonics, resonances or unbalance is present. Single-phase inverter controller designs based on the use of a synchronous rotating reference frame have been proposed, but such designs do not always perform as well as expected. This thesis aims to improve single-phase voltage-source inverters. The main objective is to address, in terms of cost, efficiency, power management and power quality, the problems found with single-phase designs based on a synchronous rotating frame single-phase inverter controller. Consequently, this thesis focuses on a novel controller approach in order to obtain a more reliable and flexible single-phase inverter. As the first step, this thesis investigates the single-phase inverter switching gate-drive algorithms and develops a form of space-vector pulse-width-modulation (SVPWM) in order to reduce total harmonic distortion. The results of the new SVPWM algorithm demonstrate its superior performance when compared with sinusoidal pulse-width-modulation (SPWM) which is often used with single-phase inverters. The second step, which is further reviewed and presented in this thesis, is the modelling of the single-phase inverter control based on the synchronous rotating frame. A mathematical analysis is conducted to determine the mechanism of the coupling that exists between the voltage phase and amplitude terms, and a new transformation strategy is proposed based on using the voltage phase as a reference at the Park transformation stages, and the current phase as a reference for the current at the transformation stages. The line-frequency components of the feedback signals are transformed to time-invariant components, thus eliminating the ripple and reducing the computational burden associated with the controller stage. Consequently, the inverter feedback controller stage is designed so that the coupling terms are decoupled within the controller itself. The effectiveness of the techniques proposed in this thesis are demonstrated by simulation using the MATLAB/SIMULINK environment. The proposed technique was also investigated through a practical implementation of the control system using a Digital Signal Processor (DSP) and a single-phase inverter. This practical system was tested up to 1 kW only (limited by the available inverter hardware). Nevertheless, the correlation between the simulation and the practical results is high and this gives confidence that the developed mechanism will allow the 2.5kW goal to be achieved. Practical test cases illustrate the effectiveness of the models. In addition, the comparisons between experimental and simulation results permit the system's behaviour and performance to be accurately evaluated. With the development of the new controller, small-scale single-phase renewable energy systems will become more useful in the field of power quality management through their ability to separately control the phase and amplitude of the output voltage. Consequently, incorporation of this type of generator within the national electrical distribution network, as distributed generators (DG) at low-voltage level, can assist with power quality management at the consumer side of the grid. In addition, such a generator can also operate in stand-alone mode if the grid becomes unavailable. The third step in this thesis investigates small-scale single-phase renewable energy systems operating as decentralized distributed generators within a local network. This operation is achieved by controlling the inverter side using the quantities measured at the common coupling point between the grid and the inverter, without requiring other extensive communications. Thus, the small-scale single-phase renewable energy distributed generator systems will contain only a local controller at each installation.

Renewable energies, and among them solar photovoltaics, are becoming more important in the last years due to the lack of fossil fuels and the environmental impact of them. PV installed capacity is increasing over and over in some countries and the prices of the installation are decreasing while the prices of the electricity are predicted to increase. Electricity use in buildings account for an important part of all electricity use in the world. This two facts make the PV installation in the rooftops of buildings a good opportunity to reduce the purchase of electricity from the grid.   The aim of the thesis is to analyze the profitability and the environmental impact (when using a hot water accumulator) of a PV system with different storage systems placed in the rooftop of two dwellings located in Gävle (Sweden). The storage systems can be either batteries or hot water accumulators. The purpose of the storage system is to increase the self-consumption rate of the PV system and to save the highest amount of money possible. It is also studied the difference of installing PbA and Li-ion batteries, and the reliability of the data used in the simulation of the alternative systems with the help of the software PVsyst.   Results show that the profitability of the proposed three alternative PV systems with storage is not higher than the PV system without storage. The reason for this has been found in the low prices of electricity and DH nowadays. Moreover, the impact of decreasing the heating demand from DH network does not benefit the environment, because the electricity has to be produced in power plants that produce more pollutants. It can be said also that the data obtained in PVsyst has been determined reliable and that the difference between the two types of batteries is not conclusive.   It can be concluded that if the cost of the PV systems or the batteries would decrease, the profitability will be higher. Furthermore, the increase in the price of electricity, DH or governmental subsidies would improve the results.

Natural disasters and conflicts in many different parts of the world force thousands of people to get displaced from their homes and live in refugee camps temporarily or permanently. For refugee families, lack of energy access has great impact on their lives. Tarpon Solar Company has developed a solar tent which is a combination of laminated cloth and flexible solar cells. In addition to producing renewable electricity, it can create a comfortable outdoor shelter from sun, rain and wind.   The aims of this study were to define and size the solar system of the tent in both AC and DC systems and optimize the tent to work in different locations around the world. Besides designing a monitoring system for the solar tent to evaluate the performance. In addition, defining the social aspect and the consumer behavior for a better solar tent future design. As a case study, Tarpon AC solar tent in Glava, Sweden has been installed to cover the basic needs of the tent users. To understand the solar tent performance in different weather zones, 4 different locations were suggested. A monitor system was designed to monitor the tent solar system performance. The simulation software PVsyst was used to size the PV system in the different locations with different solar data.   The PVsyst simulation results showed that the current Tarpon solar tent with 32 photovoltaic modules is extremely oversized to cover the basic needs loads (Lighting, mobile charging and ventilation) in the emergency cases.   The current Tarpon solar tent has a standard number of photovoltaic modules integrated in the tent fabric while the photovoltaic modules number should vary from one location to another according to the weather data and solar irradiation. In this case the current Tarpon solar system used in Glava, Sweden can be optimized by decreasing the number of photovoltaic modules to only 6 photovoltaic modules instead of 32 modules.   The study also shows that the features of the off-grid system components (battery and charge controller) are different from one location to another according to the criteria of selection.   This study concludes that for the temporary short-term emergency use of the tent where only basic needs loads are needed, DC system is better than AC system in terms of energy efficiency, system size and cost in the different proposed locations. While AC system is better when using the tent for prolonged time in terms of user flexibility and ability to extend the system. Understanding the consumer behavior and the goal of the tent whether to be used for an emergency short term shelter or a permanent shelter for a prolonged time are important factors for a better solar tent design.

As renewable energy plays an increasingly important role in the power system, the addition of PV systems to the distribution network has become a major trend in the current power system development. However, if a PV system with excessive capacity is added to the distribution network, voltage problems may occur in the system. Hence, it is important to determine the capacity of the PV system that can be added at the distribution system. The thesis aims to identify the major factors that affect the PV hosting capacity of distribution systems. The thesis studies various scenarios for the IEEE-123 test network PV system and evaluates the PV hosting capacity of the distribution system based on simulation tools including Matlab and Opendss software.

There are a number of factors that influence both the physical and the economical performance of a photovoltaic solar energy (PV) installation. The aim of this project was to develop a simulation and optimization model with which these factors could be analyzed and the PV installation optimized. By supplying the model with meteorological data, electricity consumption data and available building surfaces the model finds the optimum PV installation. The output consists of both physical and economical performance as well as information on how to distribute and install the PV modules on the available building surfaces. The model was validated using annual and hourly measurement data from Swedish PV installations. The validation shows that the model is a reliable tool for simulating the electricity generation from a PV system. In the second part of the project the model was used to evaluate the PV potential at two different hospitals and one health care center within the Uppsala County, Sweden. The model was also used to study the effect of different house orientations on the PV potential in Swedish neighborhoods. The physical and economical PV potentials are high for the hospitals and the health carecenter. This is mainly due to a high electricity demand but also due to a good match between the load profile and the PV electricity generation profile. The study on different neighborhoods shows that for gable roof buildings it might be more favorable to plan the houses so that the roofs face east-west rather than north-south. / Det är många faktorer som påverkar de fysikaliska och ekonomiska resultaten av en planerad solcellsinstallation. Syftet med det här projektet var att utveckla en simulerings- och optimeringsmodell med vars hjälp det skulle gå att analysera dessa frågor och hitta det bästa installationsalternativet i varje enskilt fall. Modellen som togs fram i detta projekt kan både studera ett givet installationsalternativ och räkna ut den mest optimala installationen utifrån de av användaren specificerade målen och begränsningarna. För att kunna göra detta behöver modellen förses med meteorologiska data för den aktuella platsen, elkonsumtionsdata från det aktuella objektet samt mått och orienteringar för de tillgängliga byggnadsytorna. Dessutom behöver användaren ange vissa ekonomiska parametrar såsom exempelvis avbetalningstid, ränta och aktuellt solcellspris. Resultatet från modellen består av både fysikaliska och ekonomiska resultat, exempelvis timvis nettoflöde av elektricitet, avbetalningstid och genomsnittligt elpris från solcellssystemet. I optimeringsresultatet redovisas hur solcellerna bör fördelas och installeras på de olika byggnadsytorna för att ge bäst resultat enligt målspecifikationen. För att validera modellen jämfördes dess simuleringsresultat med årliga och timvisa mätvärden från svenska solcellsanläggningar. Dessutom jämfördes modellens resultat med motsvarande resultat från andra simuleringsverktyg för solceller. Valideringsresultaten visar att modellen är ett pålitligt verktyg för att simulera elgenereringen från solcellsystem med olika moduler, växelriktare och installationssätt. Som ett delresultat vid modellutvecklingen simulerades ett stort antal olika solcellssystempå platta och svagt lutande tak. Utifrån dessa simuleringar utformades ett antal tumregler för hur uppvinklade moduler på platta eller svagt lutande tak skall monteras. Tumreglerna visar vilket avstånd mellan modulraderna och vilken vinkel på modulerna som ger den högsta taktäckningsgarden (största installationen) vid olika övre gränser för de interna skuggningsförlusterna. I projektets andra del användes modellen för att utvärdera solcellspotentialen på Akademiska sjukhuset, Enköpings lasarett och Tierps vårdcentral. Resultaten som levererades till Landstinget i Uppsala län visar att både den tekniska och den ekonomiska solcellspotentialen är stor på dessa enheter. Huvudanledning till den höga potentialen är att elbehovet är väldigt stort på dessa enheter samt att solcellernas elgenereringsprofil stämmer mycket väl överens med när elbehovet är som störst. Modellen användes även för att studera hur olika byggnadsorienteringar påverkar solcellspotentialen i olika tänkbara svenska bostadsområden. De olika resultaten från dessa studier visar att det i många fall är bättre att orientera byggnader med sadeltak så att taken pekar i östlig och västlig riktning snarare än mot syd och nord. Därmed föreslås en översyn avde nu rådande rekommendationerna att optimera huvudorienteringarna av taken mod syd vid detaljplanering av stadsdelar.

This thesis focuses on using photovoltaic produced electricity to power air conditioners in a tropical climate. The study takes place in Surabaya, Indonesia at two different locations the classroom, located at the UBAYA campus and the home office, 10 km away. Indonesia has an average solar irradiation of about 4.8 kWh/m²/day (PWC Indonesia, 2013) which is for ideal conditions for these tests. At the home office, tests were conducted on different photovoltaic systems. A series of measuring devices recorded the performance of the 800 W PV system and the consumption of the 1.35 kW air conditioner (cooling capacity). To have an off grid system many of the components need to be oversized. The inverter has to be oversized to meet the startup load of the air conditioner, which can be 3 to 8 times the operating power (Rozenblat, 2013). High energy consumption of the air conditioner would require a large battery storage to provide one day of autonomy. The PV systems output must at least match the consumption of the air conditioner. A grid connect system provides a much better solution with the 800 W PV system providing 80 % of the 3.5 kWh load of the air conditioner, the other 20 % coming from the grid during periods of low irradiation. In this system the startup load is provided by the grid so the inverter does not need to be oversized. With the grid-connected system, the PV panel’s production does not need to match the consumption of the air conditioner, although a smaller PV array will mean a smaller percentage of the load will be covered by PV. Using the results from the home office tests and results from measurements made in the classroom. Two different PV systems (8 kW and 12 kW) were simulated to power both the current air conditioners (COP 2.78) and new air conditioners (COP 4.0). The payback period of the systems can vary greatly depending on if a feed in tariff is awarded or not. If the feed in tariff is awarded the best system is the 12 kW system, with a payback period of 4.3 years and a levelized cost of energy at -3,334 IDR/kWh. If the feed in tariff is not granted then the 8 kW system is the best choice with a lower payback period and lower levelized cost of energy than the 12 kW system under the same conditions.

The building stock in the European Union accounts for over 40% of final energy use, where the usage of non-residential buildings may be up to 40% higher than the residential sector. Improving building energy efficiency across all categories of buildings is one key goal of the European energy policies, made prominent by the Climate and Energy package, Energy Performance of Building Directive (EPBD) and Energy Efficiency Directive (EED). In this study, a simulation model of an office-building complex utilizing district heating was created using transient simulation software TRNSYS. The model was validated using consumption data provided by the facility owner, after which an investigation of the energy saving potential along with the economic viability of adapting a new heat- and power supply system was conducted. The system designs were comprised of a geothermal energy system in combination with a PV-system and electricity storage. It was concluded that the systems were sufficient in maintaining an adequate indoor climate. Furthermore, the investments were ascertained as profitable and resulted in a decreased building specific energy demand.

The current energy situation is taking a turn towards renewable energies, due to the new pacts to curb global warming. These agreements, together with governmental aid, are facilitating an escalation in the production and improvement of new energy systems and the price decrease due to a larger-scale production. Within these energy alternatives, solar energy is found, specifically the subject to be treated in this project is photovoltaic energy, due to its exponential growth in the last 10 years, new tools are being developed for its monitoring and modelling. Therefore, the main objective of this thesis is to develop a method  for installation testing of a PV-system. The method should give the installed nominal power of the system and show if the maximum power point trackers work as expected. A large PV-system was installed on the roof of Gävle Arenaby during 2017. A measurement system for monitoring of the power of the system and of the solar irradiance was installed. Different parameters have been taken into account for the adjustment of the model that vary the performance of the system. These factors are: the irradiance received, the module temperature and the angle of incidence. It has been concluded that the results obtained indicate a correct adjustment of the theoretical power against the real power, which means, a correct operation of the generated model. Besides, the expected power follows a linear trend, reaching the power set by the manufacturer for Standard Test Conditions. The results show that the monitored modules-strings fulffill the promised performance and the method for installation testing work as expected. The linear correlation between corrected power and irradiance means that the maximum power point tracker in the inverter works independent of the power.

Utbyggnaden av PV‑system (solcellsanläggningar) har ökat exponentiellt under senare år, både internationellt och i Sverige. Några av anledningarna till detta är framförallt att tekniken blir billigare och allt mer effektiv, samt att tekniken ses som en av lösningarna på problematiken kring klimatförändringar. Trots detta behövs ändå i många fall ekonomiska bidrag för att solcellsanläggningar ska bli lönsamma, och även om solceller inte ger upphov till utsläpp av växthusgaser i driftsfasen så är emissionerna betydande i tillverkningsprocessen av systemkomponenterna. I denna fallstudie framläggs en elintensiv industribyggnad i södra Norrland som föremål för att undersöka tekniska, ekonomiska och klimatrelaterade aspekter vid en potentiell installation av solceller. Det huvudsakliga syftet var att först dimensionera lämpliga PV‑system för att sedan kunna utföra nödvändiga beräkningar gällande ekonomiska återbetalningstider för att kunna fastslå om solcellsanläggningar kan göras lönsamma inom tillverkningsindustrin. Dessutom skulle en omfattande klimatpåverkansanalys utföras för dessa typer av system. Dimensioneringen utfördes genom att först insamla data av kvantitativ karaktär genom mätningar och undersökningar av studieobjektet. Simuleringar utfördes därefter för att fastställa optimala villkor varpå olika system kunde utformas av väletablerade aktörer på solcellsmarknaden. Dessa system fungerade sedan som grund för beräkningarna av återbetalningstider. För klimatpåverkansanalysen jämfördes tre utsläppsscenarion från PV‑system med olika fall av rådande elmix. Dessa data var insamlade genom en omfattande litteraturstudie. Resultatet visar att det går att få solcellsanläggningar ekonomiskt lönsamma inom tillverkningsindustrin, men sannolikt endast med hjälp av ekonomiska bidrag. Även med bidrag så tycks lönsamheten vara betydligt sämre än för exempelvis privata hushåll. Utöver detta kan tillverkningsindustrier i vissa fall tjäna mer på att sälja el till nätet än att spara el, vilket är det diametralt motsatta andra aktörer. Klimatpåverkansanalysen visar att PV‑system genererar en uppenbar klimatnytta utanför Sveriges gränser, men tycks också påvisa att dessa potentiellt kan öka utsläppen i den svenska elmixen. Detta kan innebära att solceller i Sverige ger en negativ klimatpåverkan lokalt, men en positiv globalt, tack vare ökad export av el till följd av en utbyggnad av solcellsanläggningar. Nyckelord: PV‑system, dimensionering, optimering, tillverkningsindustri, ekonomisk återbetalningstid, växthusgasutsläpp, elmix. / The construction of photovoltaic systems has seen an exponential growth in recent years, both internationally and in Sweden. This is mainly due to declining costs and a technology that is getting more efficient while also being seen upon as one of the solutions on the issues regarding climate change. Despite this economic support schemes are often necessary for making PV‑systems profitable, and even though these systems do not generate greenhouse gas emissions during the operating phase, they emit a significant amount during the manufacturing processes of the components. In this case study technical, economical and climate related aspects surrounding a potential PV‑installation in an electric intense industry building in southern Norrland are investigated. The main purpose of this study was to dimension suitable PV‑systems to conduct necessary calculations concerning economical payback times to establish whether PV‑installations can be made profitable within the manufacturing industry. In addition to this a climate impact analysis was going to be made for such systems. The dimensioning process was conducted by firstly gathering quantitative data through measurements and investigations of the object. Thereafter simulations were run to establish optimized conditions for which different PV‑systems could be modelled by companies active in the field. These systems where then used as a foundation to make the necessary calculations regarding payback time. For the climate impact analysis three emission scenarios from PV‑systems where put together and compared to emissions from different cases of electricity production. These data were collected through a comprehensive literature review. The results show that PV‑systems can be profitable within the manufacturing industry, but most likely only with economic support schemes. Even with economic support the profitability is far less than that of private households. Also, industries, in some cases, seem to make more money selling excess electricity rather than saving bought electricity. This is diametrically opposite other parties. The climate impact analysis shows that PV‑systems are highly efficient when it comes to climate change mitigation outside Sweden´s boarders, but also seem to show that they might increase the amount of emissions in Sweden´s electricity mix. This might mean that PV‑installations in Sweden has a negative effect locally, but a positive effect globally, due to a possible increase in exported electricity from Sweden as the number of installations increase.    Keywords: PV system, dimensioning, optimization, manufacturing industry, economic payback time, greenhouse gas emissions, electricity mix.

Submitted by Patrícia Cerveira (pcerveira1@gmail.com) on 2017-06-07T20:58:56Z No. of bitstreams: 1 IVAN MACHADO_Dissertação.pdf: 4344558 bytes, checksum: 054d635d2c21036a970f1a9ead057382 (MD5) / Approved for entry into archive by Biblioteca da Escola de Engenharia (bee@ndc.uff.br) on 2017-07-03T13:10:58Z (GMT) No. of bitstreams: 1 IVAN MACHADO_Dissertação.pdf: 4344558 bytes, checksum: 054d635d2c21036a970f1a9ead057382 (MD5) / Made available in DSpace on 2017-07-03T13:10:58Z (GMT). No. of bitstreams: 1 IVAN MACHADO_Dissertação.pdf: 4344558 bytes, checksum: 054d635d2c21036a970f1a9ead057382 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Atualmente diversos países tem posto em prática políticas para promover a Geração Distribuída (GD). No Brasil, a Agência Nacional de Energia Elétrica (ANEEL) publicou a Resolução 482/2012 a fim de estabelecer as condições gerais de acesso da geração distribuída à rede e o mecanismo de compensação para a energia gerada pelo consumidor. Entre as tecnologias de GD, a solar fotovoltaica desempenha um papel importante devido aos seus avanços, em conjunto com a redução dos custos de capital e subsídios. A incerteza da inserção de unidades de GD renováveis pode causar impactos no sistema de distribuição de energia e vários estudos têm sido realizados para analisar os problemas relacionados a penetração da GD fotovoltaica. No entanto, em geral, esses estudos consideram cenários de penetração gerados aleatoriamente ou com base em aspectos técnicos, independentemente das características econômicas dos clientes. Portanto, esse trabalho propõe uma metodologia para avaliar o impacto da GD no sistema de distribuição considerando cenários de adoção com base nos clientes. O estudo de um alimentador de distribuição real foi desenvolvido a partir de dados do Projeto “Cidade Inteligente Búzios”. A análise e a simulação desse sistema de distribuição foram realizadas através do software Open Distribution System Simulator (OpenDSS). / Nowadays, several countries are applying energy policies to promote Distributed Generation (DG). In Brazil, the National Electric Energy Agency (ANEEL) published the Normative Resolution 482/2012 in order to establish the general conditions for access of distributed generation for the grid and compensation mechanisms for the energy generated by the consumer. Among DG technologies, solar photovoltaic plays a major role due to advances in photovoltaic technology, combined with decreasing capital costs and subsidies. The uncertainty renewable DG integration may cause impact on distribution power system and several studies have been carried out to analyze grid integration issues associated with photovoltaic DG penetration. However, in general, these studies consider penetration scenarios randomly generated or based on technical aspects, regardless economic characteristics of customers. Therefore, this paper proposes a methodology to assess the impact of DG on distribution system considering customer adoption scenarios. The study of a real distribution feeder was developed from “Smart City Búzios” project database. The analysis and the distribution system simulation were performed with the Open Distribution System Simulator Software (OpenDSS).