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Narava nas čedalje bolj opozarja, da bo za dobrobit našega življenjskega okolja potrebno večji del proizvodnje električne energije nadomestiti z obnovljivimi viri energije, eden izmed teh so tudi sončne celice, ki so osnova fotonapetostnih (PV) sistemov. Za razumevanje delovanja PV sistemov pa je pomembno, da to področje vpeljemo v različne nivoje študija elektrotehnike. Magistrska naloga predstavlja načrtovanje in izvedbo učnega pripomočka za demonstracijo delovanja sončnih celic in PV modulov, s pomočjo katerega bodo študentje podrobno spoznali delovanje PV sistemov. V ta namen smo izdelali model PV modula, ki je sestavljen iz 60-tih sončnih celic, zaščitnih diod in temperaturnega senzorja ter napravo, ki omogoča merjenje električnih napetosti vseh sončnih celic PV modula, jakost električnega toka, temperature in osvetljenosti modula. V napravi je izvedeno tudi programsko nastavljivo breme, ki omogoča obremenitev in zajemanje I-U karakteristike PV modula. Nadzor merjenja in ogled rezultatov meritev se izvaja s programom na osebnem računalniku, za prenos podatkov med osebnim računalnikom in napravo se uporablja Modbus RTU komunikacijski protokol. Naprava omogoča detajlni vpogled v karakteristiko PV modula na nivoju posameznih celic v različnih pogojih delovanja glede osvetlitve, delnega senčenja in temperature in predstavlja učinkovit učni pripomoček za študij fotovoltaike. Nature often reminds us that we must use more renewable energy if we want to save our environment. One type of renewable energy is electricity produced from photovoltaic (PV) systems. To understand how PV systems work, it is very important to implement this subject into all levels of the study of electrical engineering. This master's thesis represents the development and implementation of a demonstration tool for solar cells and modules. This tool allows students to learn about the operation of PV systems in detail. A miniature PV module consisting of 60 solar cells, protection diodes and a temperature sensor was made for this purpose. We also developed a device that measures the voltages of all solar cells, their current, the temperature and the irradiance of the PV module. The device is also equipped with an adjustable electronic load which enables loading in different operational points as well as acquiring the I-V characteristics. A PC application allows for controlling measurements and viewing the results. The Modbus RTU protocol is used for transferring data between a PC and the demonstration tool. With this demonstration tool it is possible to view in detail the influence of illumination, shading, and temperature on each one of the PV cells in the PV module.

V magistrskem delu se ukvarjamo z razvojem merilne naprave za testanje sončnih celic in mini-modulov v različnih delovnih točkah, namenjeno uporabi v zunanjih ali notranjih pogojih. Naloga naprave je, da nastavi izbrano napetost in izmeri tok in napetost na testirani celici ali mini-modulu. Naprava lahko testira do šest vzorcev istočasno. Naprava nudi štiri kvadrantno delovanje na širokem napetostnem (±12 V) in tokovnem (±50 mA) območju, kar zagotavlja podporo širokemu naboru celic in mini-modulov laboratorijske izdelave. Komunikacija z napravo poteka skladno s SCPI protokolom prek USB vodila. S tem je naprava sposobna opraviti prelet IU karakteristike, sledenje točki maksimalne moči in testiranje celic pri negativni napetosti. V delu je prikazana praktična uporaba vseh treh testov na silicijevi celici, perovskitni celici in perovskitnem mini-modulu. Predlagan koncept naprave se je izkazal s svojo uporabnostjo in predstavlja dobra osnovo za razširitev funkcionalnosti na večjo, 24 kanalno, modularno verzijo. In this master’s thesis, an instrument for testing solar cells and mini-modules in different operating points was developed, suitable for outdoor and indoor use. The task of the instrument is to set the desired voltage at the output and measure the current and voltage of the connected cell or mini-module. The instrument can test up to six samples simultaneously. It offers four-quadrant operation in a wide voltage (±12 V) and current (±50 mA) range, which ensures support for a wide range of lab-scale cells and mini-modules. Communication with the instrument is compliant with the SCPI protocol via USB. Thus, the instrument is able to perform a JV sweep, maximum power point tracking, and testing in reverse bias. The functionality of the instrument in performing all three tests is evaluated using silicon cells, perovskite cells, and perovskite mini-modules. The instrument proves to be a valuable tool for evaluating solar cell and mini-module performance and provides a good proof of concept for the development of a larger, 24-channel modular version.

Ob priključenem primernem zunanjem napajanju na sončno celico ta prične oddajati elektromagnetno sevanje. Slikanje tega pojava, ki se imenuje elektroluminiscenca (EL), je uporabno za prostorsko razčlenjeno karakterizacijo sončnih celic. Ker je proces slikanja v nekaterih primerih dolgotrajen, je bila na mestu izvedba njegove avtomatizacije. Projekt je bil izveden v Laboratoriju za fotovoltaiko in optoelektroniko (LPVO) na Fakulteti za elektrotehniko (FE) v Ljubljani. Nadgradnja sistema za slikanje je zajemala predvsem menjavo držala za kamero s triosnim pomičnim sistemom in razvoj novega programa za krmiljenje procesa slikanja. Iskani triosni sistem je sistem, podoben 3D tiskalniku. Ker se je interna predelava slednjega izkazala za neekonomično, smo izdelavo novega triosnega sistema naročili pri zunanjem izvajalcu. Obstoječi program za krmiljenje slikanja, napisan v programskem jeziku MATLAB, je bil osnova za nov program, napisan v programskem jeziku Python. V novem programu je bil za razvoj grafičnega uporabniškega vmesnika uporabljen modul PyQt5 in za izvajanje sočasnih nalog modul threading. Program krmili kamero, triosni sistem in napajalnik. Poleg 14 Pythonovih modulov se v njegovem direktoriju nahajajo še datoteke z definicijami grafičnih uporabniških vmesnikov, dinamično povezana knjižnica s funkcijami za krmiljenje kamere in nekaj drugih datotek in map. Poleg omenjenih datotek za polno delovanje potrebuje tudi program z imenom Keysight Connection Expert. Novorazviti program omogoča načrtovanje postopka za slikanje EL in njegovo deloma avtomatizirano izvedbo. Za popolno avtomatizacijo je potrebno izdelati še mehanizem za ostrenje slike. Modularna zasnova programa naj bi programerju omogočila hiter pregled obstoječih funkcij in enostaven začetek nadgrajevanja. When a suitable external power supply is connected to the solar cell, it starts emitting electromagnetic radiation. Imaging this phenomenon, called electroluminescence (EL), is useful for spatially resolved characterisation of solar cells. As the imaging process is in some cases time-consuming, it was necessary to automate it. The project was carried out at the Laboratory of Photovoltaics and Optoelectronics (LPVO) at the Faculty of Electrical Engineering (FE) in Ljubljana. The upgrade of the imaging system consisted mainly of replacing the camera holder with a three-axis system and developing a new program to control the imaging process. The three-axis system is a system similar to a 3D printer. As it proved uneconomical to modify the latter in-house, we outsourced the construction of the new three-axis system to a 3D printer manufacturer. An existing imaging control program written in MATLAB was the basis for a new program written in Python. The new program used the PyQt5 module to develop the graphical user interface and the threading module to perform concurrent tasks. The program controls the camera, the three-axis system and the power supply. In addition to the 14 Python modules, its directory contains files with graphical user interface definitions, a dynamic link library used for controlling the camera and a few other files and folders. In addition to these files, a program called Keysight Connection Expert is required for full operation. The newly developed program allows the EL imaging process to be planned and partially automated. For full automation, an image focusing mechanism has to be developed. The modular design of the program should allow the programmer to quickly review existing functions and easily start the upgrade process.

Diplomsko delo zajema področje modeliranja in razvoja sončnih celic. S pomočjo simulatorja CROWM (Combined Ray Optics/Wave Optics Model), ki deluje na osnovi kombinacije geometrijske in valovne optike, bomo modelirali sončne celice z različnimi naključno hrapavimi površinami med sloji materialov. Prvotno je bil izdelan generator naključno hrapavih površin z izračunavanjem efektivne hrapavosti ter korelacijske dolžine. Omenjena parametra uporabljamo za ločevanje naključno hrapavih površin. Sledil je razvoj avtomatizacijskega programa, ki nam zaporedno generira površino ter izvede simulacijo. Na koncu smo ovrednotili vpliv različnih naključno hrapavih površin na izkoristek simuliranih sončnih celic. The thesis covers the field of modeling and development of solar cells. With the help of the CROWM (Combined Ray Optics/Wave Optics Model) simulator, which works on the basis of geometrical and wave optics, we will model solar cells with different randomly textured surfaces between layers of materials. Originally, a generator of randomly textured surfaces was created with calculations of the effective roughness and the correlation length. We use the mentioned parameters to separate and classify randomly textured surfaces. This was followed by the development of an automation program that sequentially generates the surface for us and performs the simulation. Finally, we evaluated the influence of different randomly textured surfaces on the efficiency of the simulated solar cells.

Diplomsko delo zajema aktualno tematiko glede obnovljivih virov za proizvodnjo električne energije. Fosilna goriva postajajo vedno večji problem, ki negativno vpliva na okolje. Zato se vedno bolj posvečamo k uporabi obnovljivih virov energije. Trenutno najbolj v porastu sta obnovljiva vira energije veter in Sonce. Namen diplomskega dela je podati osnove pridobivanja električne energije z izkoriščanjem sončnega sevanja v sončni elektrarni in proučiti možnost samooskrbe. Za čas, ko na razpolago ni dovolj sončnega sevanja, je potrebno proučiti velikost baterije kot shranjevalnika energije in oceniti njeno ustreznost. Prvi del diplomskega dela je namenjen kratki zgodovini o začetkih uporabe sončne energije, fotovoltaičnem efektu, shranjevanju energije in prvim shranjevalnikom električnega naboja oz. bateriji. Drugi del je bolj teoretično obarvan in v tem delu se bralec seznani z delovanjem sončne celice, nastanku tok v njej in spozna tipe sončnih celic ter delovanje baterije. Sledi raziskovalni del, pri katerem smo opazovali zastavljen model sončne elektrarne in hrambo električne energije. Glede na to, da intenzivnost sončnega obsevanja skozi letne čase variira, sem se odločil proizvodnji razdeliti na letne čase. Pričakovano bo v poletnem času največja količina proizvedene električne energije njena povprečna vrednost je znašala 495,21 kWh/dan, sledi ji proizvodnja spomladi z 448,83 kWh/dan, nato jesensko obdobje z 170 kWh/dan in najmanj proizvedemo pozimi povprečno 161 kWh/dan. Kakor se spreminja moč, se posledično spreminja tudi raba baterije. Baterijo je potrebno izbrati na podlagi obdobja, v katerem imamo najmanjšo proizvodnjo v našem primeru je to zima. Kapaciteta baterije, ki nam pride v poštev se v odvisnosti od mere izpraznitve, giblje med 2529 Ah in 3502 Ah odvisno od deleža praznjenja baterije. Če pa bi namesto zimskega povprečja upoštevali najslabše razmere, ko več dni ni Sonca, pa bi potrebovali še močnejšo baterijo. The diploma thesis covers current topics regarding renewable sources for the production of electricity. Fossil fuels are becoming a growing problem that has a negative impact on the environment. That is why we are increasingly focusing on the use of renewable energy sources. Currently, the most growing renewable energy sources are wind and the Sun. The purpose of the thesis is to provide the basics of obtaining electricity by utilizing solar radiation in a solar power plant and to examine the possibility of self-sufficiency. For the time when there is not enough solar radiation available, it is necessary to study the size of the battery as an energy store and assess its adequacy. The first part of the thesis is devoted to a brief history of the beginnings of using solar energy, the photovoltaic effect, energy storage and the first electric charge storage devices, or batteries. Second part is more theoretical, and in this part the reader learns about the operation of a solar cell, the generation of current in it, and learns about the types of solar cells and the operation of the battery. The following is the research part, during which we observed the set model of the solar power plant and the storage of electricity. We find that the production of electricity is conditioned by solar radiation, which changes over time, and the power of production follows this as well. Given that the intensity of solar radiation varies throughout the seasons, I decided to divide the production into seasons. It is expected that the largest amount of electricity produced will be in the summer time, its average value was 495.21 kWh/day, followed by production in the spring with 448.83 kWh/day, then the autumn period with 170 kWh/day and the least produced in the winter is an average of 161 kWh/day day. As power changes, so does battery usage. The battery must be selected based on the period in which we have the smallest production, in our case it is winter. We choose a battery for the 48 V voltage system, which allows us to have a smaller battery and less losses. Size Capacity Bbaterijae, which comes into consideration depending on the degree of discharge, varies between 2529 Ah and 3502 Ah. Depending on how many percentages we want our batteries to be discharged. But if, instead of the winter average, we took into account the worst conditions, when there is no sun for several days, we would need an even more powerful battery.

Perovskit je rumen, rjav ali črn mineral s kemijsko formulo CaTiO3. Splošna formula perovskitne strukture je ABM3. Perovskiti so privlačne spojine za različne aplikacije, ker izkazujejo zanimive fizikalne in kemijske lastnosti, kot so elektronska prevodnost, električno aktivna struktura, gibljivost kisikovih ionov skozi kristalno mrežo, toplotna in kemijska stabilnost ter magnetne, multiferoične in termoelektrične lastnosti. Nekateri perovskitni materiali so zelo obetavni kandidati za izboljšanje učinkovitosti anodnih katalizatorjev, drugi so pokazali odlične absorpcijske lastnosti za fotovoltaične sončne celice, tretji se lahko uporabljajo za elektrokemijsko zaznavanje alkoholov, glukoze, plinov ... V zadnjem času so anorgansko-organski perovskitni materiali pritegnili veliko zanimanja zaradi njihove kemijske variabilnosti, strukturne raznolikosti in izjemnih fizikalnih lastnosti. Poudarek raziskav je zlasti na različnih metodah ugotavljanja lastnosti perovskitov in z njimi povezane uporabe. Perovskite is a yellow, brown, or black mineral with the chemical formula CaTiO3. The general perovskite structure formula is ABM3. Perovskites are attractive compounds for a variety of applications because they exhibit interesting physical and chemical properties such as electronic conductivity, electrically active structure, the oxide ions mobility through the crystal lattice, thermal and chemical stability, and magnetic, multiferroic and thermoelectric properties. Some perovskite materials are very promising candidates for improving the efficiency of anode catalysts, some have shown excellent absorption properties for photovoltaic solar cells, and others can be used for electrochemical sensing of alcohols, glucose, gases … Recently, inorganic-organic perovskite materials have attracted substantial interest due to their chemical variability, structural diversity, and outstanding physical properties. Current research is focused on different methods for determining the properties of perovskites and their related applications.

V magistrski nalogi smo raziskali vpliv dodanega MAPbBr3 k osnovni FACs perovskitni kompoziciji na posamezne fotovoltaične parametre sončne celice ter na njihovo dolgoročno in temperaturno stabilnost. Perovskitne kompozicije brez metilamonija (MA), na primer t.i. FACs kompozicija, se v zadnjem času pogosteje uporabljajo zaradi večje temperaturne stabilnosti. Zaradi hlapenja pri relativno nizkih temperaturah povzroča MA težave pri postopku enkapsulacije in negativno vpliva na dolgoročne stabilnosti sončnih celic. Po drugi strani pa dodatek MA h kompoziciji perovskita omogoča lažjo formacijo filmov, posledica česar je višji PCE. Z višanjem deleža MA narašča tudi širina energijske reže, kar lahko koristno uporabimo za izdelavo tandemskih celic v kombinaciji s silicijem. Zaradi teh pozitivnih lastnosti MA je vredno podrobneje raziskati, v kolikšni meri le-te še pretehtajo nad njegovimi slabostmi. Za namen magistrske naloge smo izdelali dve seriji celic. V prvi smo ugotavljali vpliv dveh različnih anti-topil, uporabljenih v postopku spinskega nanašanja perovskita, v drugi pa vpliv različnih količin dodanega MAPbBr3 na lastnosti celice. V pomoč pri meritvah in obdelavi rezultatov smo uporabili različne merilne sisteme za karakterizacijo celic, razvili pa smo tudi merilni sistem za meritve suns-VOC. Za vsako kompozicijo smo izdelali visoko učinkovite perovskitne sončne celice, z učinkovitostjo pretvorbe (PCE) nad 19 %. V povprečju smo najvišje PCE in faktorje polnjenja (FF) dobili pri celicah z 0-% in 6-% dodatkom MAPbBr3, čeprav imajo tudi pri ostalih dveh kompozicijah nekatere celice PCE nad 19 % in FF nad 75 %. Rezultati I-U meritev so pokazali tudi, da z dodanim MAPbBr3 Voc narašča, Jsc pa upada. Iz rezultatov meritev EQE, fotoluminiscence in transmisije smo potrdili, da se z višanjem deleža MAPbBr3 energijska reža perovskita širi. Za kompozicijo z 10-% deležem MAPbBr3 smo pomerili energijsko režo 1.69 eV, kar je optimalno za perovskitno-silicijeve tandemske sončne celice. Iz meritev suns-VOC smo določili faktor idealnosti n, nato pa smo celice podvrgli še temperaturni obremenitvi in izvedli sledenje maksimalni točki moči (MPP). Ugotovili smo, da celice z višjim deležem MAPbBr3 hitreje degradirajo, sploh v primeru 10-% deleža. V ostalih primerih to ni tako izrazito, še zmeraj pa je razviden trend upada PV parametrov. V magistrskem delu smo tako določili, da je kljub dobrim rezultatom z različnimi dodatki MAPbBr3 še vedno najboljša kompozicija FACs zaradi njene boljše temperaturne stabilnosti. In this thesis, we investigated the influence of MAPbBr3 added to a basic FACs perovskite composition on the PV parameters of a solar cell, and on their long-term and temperature stability. Methylammonium-free (MA) perovskite solar cells have recently gained popularity due to their higher thermal stability. Due to its volatility at relatively low temperatures, MA causes problems in the encapsulation process and has a negative impact on the long-term stability of the solar cells. On the other hand, the addition of MA to the perovskite composition allows for easier film formation, resulting in a higher PCE. As the amount of MA increases, the energy gap also increases, which can be exploited for the fabrication of tandem cells in combination with silicon. All of these usefull properties of MA make it worth investigating further to see to what extent they outweigh its disadvantages. For the purpose of this thesis, two batches of cells have been fabricated. In the first one, the influence of two different anti-solvents used in the spin coating process of perovskite was investigated, and in the second one the influence of different amounts of MAPbBr3 added on the cell properties was determined. Different measurement systems were used for cell characterisation. For each composition, we fabricated highly efficient devices with power conversion efficiencies above 19%. On average, the highest PCE and FF were obtained in cells with 0% and 6% quantity of MAPbBr3, although some cells of other two compositions also mediate PCE and FF above 19% and 75% respectively. The results of the I-V measurements also showed that VOC increases while JSC decreases with the addition of MAPbBr3. From the results of EQE, photoluminescence and transmission measurements, we confirmed that the energy gap widens with increasing MAPbBr3 content. The bandgap of FACs with 10% MAPbBr3 is 1.69 eV, which is otpimal for perovskite/Si tandems. From the Sun-VOC measurements, we determined the ideality factor n. For the final measurements we subjected the cells to high temperature and maximum power point (MPP) tracking. We found that cells with higher MAPbBr3 content degrade more rapidly, especially when the content is 10%. In other cases this is not so pronounced, but there is still a trend towards a decrease in PV parameters. In the master thesis, we have therefore determined that despite overall good results, MA-free FACs is still the best composition due to its better thermal stability.

V pričujočem diplomskem delu je opisan razvoj naprave za kontrolirano ukrivljanje sončnih celic. S tem, ko celico ukrivimo se v njej pojavijo mehanske napetosti, ki povzročijo povratne in nepovratne spremembe, kot npr. pokanje materiala in kontaktnih plasti. Te lahko zaznamo z raznimi diagnostičnimi tehnikami, kot so elektro- in fotoluminiscenca. Naprava omogoča ponovljive poskuse izvajanja mehanskih obremenitev sončnih celic z znanim polmerom in silo vse do zloma sončne celice, medtem ko izvajamo meritve. Naprava je sestavljena iz dvižnega dela in vpetja sončne celice. Dvižni del vsebuje dvižno vodilo z dajalnikom pozicije in merilno celico za merjenje sile. Dvižno vodilo dviguje orodje, ki deluje neposredno na sončno celico. Z napravo nadzorovano ukrivimo sončno celico in pri tem opazujemo odzive celice glede na določen odmik ali silo. Preliminarni test naprave na polikristalni sončni celici kvadratne oblike dimenzije 156 mm x156 mm je uspel. Meritve so pokazale, da omenjena celica zdrži mehanske obremenitve do 6 N ali pomike do 45 mm, pri čemer, elektroluminiscenčni posnetki kažejo postopno formiranje razpok. This thesis discusses the development of a device suited for controlled bending of solar cells. When the solar cells bend, mechanical stress appears in it, causing reversible and irreversible changes, such as cracking of the material or contact layers. These changes can be detected by various diagnostic techniques such as electro- and photoluminescence. The presented device performes repeatable loading of a solar cell up to a predefined radius and force all the way to the breakage of the solar cell while performing measurements. The device consists of a lifting part and a solar cell mount. The lifting part contains a lifting guide with a position encoder and a measuring cell for measuring the force. The lifting guide lifts the tool, which acts directly on the solar cell. The device bends the solar cell in a controlled manner, observing the cell's responses to a certain distance or force. A preliminary test of the device on a square-shaped polycrystalline solar cell with the dimension of 156 mm x 156 mm was successful. The measurements showed that the solar cell can withstand mechanical loads of up to 6 N or displacements of up to 45 mm, with electroluminescent images showing the gradual formation of cracks.

Magistrsko delo zajema celoten proces razvoja prototipa solarno sledilnega mehanizma, tako na strojnem, programskem in električnem nivoju. Opisani so postopki razvoja in solarno sledilni algoritmi. Prototip je fizični sistem, ki s svojim algoritmom sledi sončni trajektoriji po časovni referenci. To pomeni, da za sledenje potrebuje 4 podatke in sicer: zaporedna številka dneva v letu, ure, minute in geografsko širino. Po zaključenem procesu razvoja je sledilo zbiranje in analiza rezultatov. Rezultate so podajali testi. This master thesis work presents process of developing solar tracker prototype mechanism on machine, programming and electrical level. Stages of development and solar tracking algorhytms are described. Prototype is a physical system, which tracks sun trajectory by time reference with it's algorhytm. That means that for tracking it needs 4 data which are: number of day in a year, hours, minutes and geographical lattitude. After development has ended collecting and analysis of result data were done. The results were given by tests.

Sončna energija, kot eden glavnih obnovljivih virov energije, eksponentno pridobiva kapacitete svetovne proizvodnje električne energije. Pričakovano je, da se s povečanjem števila operativnih modulov pojavlja izziv diagnostike stanja sončnih celic na način, ki bo hiter, preprost, natančen in neinvaziven. Potencial za metodo z naštetimi lastnostmi predstavlja detekcija napak s pomočjo fluorescence. Fluorescenca in fosforescenca sta kot podveji fotoluminiscence procesa, kjer material s fotoluminiscenčnimi lastnostmi oddaja svetlobo na podlagi vzbujanja atomov z elektromagnetnim valovanjem. EVA folija kot enkapsulant sončnih celic izkazuje izrazite fluorescenčne lastnosti, če ga osvetlimo z UV svetlobo. Glede na odsotnost in prisotnost fluorescence osvetljenih celic lahko ocenjujemo stanje in vrsto poškodb. Za izvedbo preizkusa in analize modulov sem izdelal prenosno UV svetilko, osnovano na UV svetlečih diodah in napajano s polnilnimi baterijami, ki omogoča hiter in enostaven pregled modulov na prostem ali v laboratoriju. Za dodatno potrditev zmožnosti prepoznavanja napak, so bile s sončne elektrarne Fakultete za elektrotehniko UL pridobljene slike 76 modulov z metodo fluorescence in elektroluminiscence, ki predstavlja eno izmed ostalih priznanih diagnostičnih metod. Zajete podatke celotnega nabora modulov sem statistično analiziral. Poleg predstavitve deleža različnih napak je predstavljen tudi rezultat ujemanja slik modulov, narejenih po obeh metodah. Ujemanje je prisotno v večini primerov, predstavljeni so tudi možni razlogi za primere, ko ujemanje ni razvidno. Na podlagi pridobljenih rezultatov je metodo fluorescence moč prepoznati kot eno izmed najlažjih in najučinkovitejših metod za analizo stanja sončnih celic in modulov z velikim potencialom za razvoj in industrializacijo. Solar energy, as one of the main sources of renewable energy, is exponentially increasing capacities in global production. It is expected that due to increase of operational modules, industry will be challenged with fast, simple, accurate and noninvasive diagnostic method. The potential for the method with the described characteristics can be found in error detection with Fluorescence. Fluorescence and Phosphorescence, as types of Photoluminescence, are processes, where material with photoluminescent properties emits light as a result of excitation of atoms with electromagnetic waves. EVA film, as encapsulation material of solar cells, shows distinct fluorescent properties, if illuminated with UV light. Based on the presence and absence of fluorescence in solar cells, status and defects can be estimated. To run an experiment and analysis of solar modules, I constructed a portable UV flashlight, based on UV light emitting diodes (LED), with rechargeable batteries that enable fast and simple overview of modules located either in the field or in the laboratory. To confirm the possibility of defect recognition, photos of 76 photovoltaic modules from a solar power plant of Faculty of Electroengineering were taken using both Fluorescence and Electroluminescence, as one of additionally recognized diagnostic method. Gathered data were statistically analyzed and shares of different defects in power plant are presented, as well as matching of observable defects with both methods. Matching is present in the majority of cases, and explanation for the possible miss match is provided. On the basis of the gathered data, method of fluorescence can be recognized as one of the easiest and most effective methods for analysis of status of solar cells and modules, with great potential for further development and industrialization.

V pričujočem delu razvijemo in izdelamo računalniški modul za krmiljenje merilne naprave za testiranje laboratorijskih sončnih celic uMPPT. Na začetku opišemo pomen preizkušanja sončnih celic v širokem razponu okoljskih pogojev in njihov vpliv na staranje celic. Predstavimo obstoječ sistem večkanalnih sledilnikov točke največje moči ter razlog za njegovo dopolnitev z lastnim računalniškim modulom. Računalniški modul je zgrajen na štiri-plastnem tiskanem vezju dimenzij 10 x 10 cm in deluje z modulom Raspberry Pi. Zaradi hitrih signalov v vezju potrebujemo linije z nadzorovano diferencialno impedanco. Modul vsebuje potrebne priključke za uporabo računalnika in priklop na merilni sistem. Za komuniciranje z merilnim delom uporabljamo vodilo RS-485, za kar smo dodali pomožni mikrokrmilnik s pripadajočo programsko opremo. Rezultat je računalniški modul in aplikacija z grafičnim uporabniškim vmesnikom, kar predstavlja osnovo za nadaljnji razvoj programske opreme. The thesis addresses design and development of a computer module for controlling the measuring instrument for testing laboratory solar cells uMPPT. We will describe the importance of testing the solar cells in wide variety of environmental conditions and its impact on solar cells aging. We will introduce the current system of multichannel maximum power point trackers and a reason for supplementing it with its own computer module. Computer module is constructed on a four-layer printed circuit board with dimensions of 10 x 10 cm and is designed to work with Raspberry Pi Compute Module. Because of the high-speed circuitry, we need differential transmission lines that have controlled impedance. Module consists of several connectors that are necessary for connecting a personal computer and the measuring system. A dedicated microcontroller with associated firmware was used for the RS-485 communication interface between measuring unit and the computer module. Result of the thesis is a computer module and application with graphical user interface, which is the base for the future software development.

V pričujočem magistrskem delu smo razvili večnamenski modularni sistem za osvetljevanje sončnih celic in manjših fotonapetostnih (PV) modulov. Za namen konstruiranja svetil smo razvili računalniški simulator polja svetlečih diod. Simulator je zmožen izvajati optimizacijo polja s spreminjanjem števila, položaja in svetilnosti svetlečih diod v polju. Simulator smo uporabili za določitev postavitve svetlečih diod, s katero lahko dosežemo nehomogenost osvetlitve pod 2 % in jakost osvetlitve 500 Wm2. Z namenom implementacije svetila smo nato razvili napajalni modul za svetleče diode, ki omogoča napajanje več najpogostejših tipov svetlečih diod v napetostnem območju 3 V–42 V in tokovnem območju 0,1 A–1 A. Omogoča tudi nastavljanje svetilnosti teh diod na 5 % natančno, meritev temperature in toka svetleče diode. S pomočjo mikrokrmilnika je implementirana digitalna komunikacija med moduli in s kontrolno enoto. Na svetilnem modulu smo preizkusili več različnih svetlečih diod in izmerili nekaj ključnih karakteristik. Za krmiljenje svetilnih modulov smo razvili kontrolno enoto na osnovi mikrokrmilnika ARM. Kontrolna enota komunicira s svetilnimi moduli in z osebnim računalnikom. Omogoča nadzor nad svetilnostjo modulov in branje njihove temperature ter toka. Svetilne module in kontrolno enoto smo združili v funkcionalno svetilo namenjeno umetnemu staranju PV-modulov in sončnih celic pod UV-svetlobo. In this thesis we developed a multipurpose modular system for solar cells and smaller photovoltaic modules illumination. For the purpose of LED array design, we developed a numerical simulator. Using numerical optimization algorithms, we can calculate the optimal number, location and power of individual LEDs in an array on a predefined area using illumination intensity and homogeneity criteria. Results of calculation were used in design of a layout for an array of LEDs that allows us to reach the illumination power density of 500 Wm2 with maximal non-homogeneity of 2 %. For the implementation of the LED light source we developed a power supply module capable of powering various typical LEDs in a voltage range of 3 V–42 V and a current range of 0,1 A–1 A. This module can also modulate the brightness of these LEDs with 5 % accuracy. LED light modules are also capable of measuring the current and temperature of the LEDs and communicating with each other and with the control unit. We tried multiple LEDs on the light module and measured some key characteristics. To control the light modules, we developed a control unit based on an ARM microcontroller. This control unit communicates with the light modules and a personal computer. It allows control of the light intensity of the light modules and monitors their temperature and output current. We have also developed the complete control module firmware. Finally, we merged the light modules and the control unit into a functional light source for artificial ageing of PV modules and solar cells under UV illumination.

V pričujočem delu smo načrtali in izdelali sončni simulator na podlagi svetlečih diod (LED) z osvetlitveno površino 30 cm x 30 cm. Na začetku predstavimo uporabo takega sistema za namen karakterizacije sončnih celic in panelov, predstavimo standarde na tem področju in nekaj primerov komercialnih rešitev, nato pa se osredotočimo na gradnjo lastnega sistema. Kot izhodišče za izdelavo je bila uporabljena zaključna naloga Žige Rojca, ki kot rezultat podaja teoretično optimalne položaje in relativne svetilnosti svetlečih diod za optimalno porazdelitev svetlobe na merilni površini. Z optimizacijskimi postopki je bila dosežena nehomogenost osvetljenega polja 0,9 % [3]. Cilj zasnove sistema je doseganje stopnje nehomogenosti pod 2 %. Če se želimo približati zahtevam po visoki stopnji homogenosti, moramo individualno krmiliti vsako izmed LED in kompenzirati vsak kanal. Zaradi želje po preprostem in relativno poceni sistemu ne zagotavljamo točnega spektra svetlobe, kar pa nas ne moti, saj se da zahtevo po točnosti spektra obiti. Končni rezultat je delujoč sončni simulator, ki je primeren za konstantno osvetlitev s prostorsko nehomogenostjo 1,9 %. Izmerjena nehomogenost je zaradi značilnega sevalnega diagrama LED in njihove bližine zelo odvisna tudi od kotne odvisnosti referenčnega senzorja, s katerim se meri. Svetlobni žarki namreč niso vzporedni. The thesis addresses design and development of a solar simulator with LEDs and illuminated area of 30 cm x 30 cm. In the beginning of the thesis we explain the need for the system for characterisation of solar cells and panels, introduce standardisation in this field and few examples of commercial solutions. Then we focus on the development of our system. The thesis from Žiga Rojec [3] which defines theoretically optimal positions and relative power outputs of LEDs, was used as the starting point. With use of various optimisation tools non-uniformity of 0,9 % was reached. Our goal for the whole system is to reach non-uniformity below 2 %. Since we want to achieve this high non-uniformity goal, we have to drive and compensate each LED channel individually. For our system to be as cheap and simple as it is possible we don't achieve correct light spectrum, as need for that can be avoided. All the LED channels are driven by the use of microcontroller. Final result is a working solar simulator, with spatial non-uniformity of 1,9 % which is capable of constant illumination. Measured non-uniformity is strongly dependent on radiation pattern of an LED as well as on the reference sensor used. Light rays are not parallel to each other.

Konec 19. stoletja so znanstveniki odkrili, da lahko energijo sonca pretvorijo v električno energijo, in tako se je začela razvijati fotovoltaika, veda, ki proučuje pretvorbo svetlobe v elektriko. Takšno delovanje ne proizvaja nobenih okolju škodljivih plinov, zato sončne celice uvrščamo med čiste vire energije, prav tako pa jih zaradi stalne prisotnosti sončne svetlobe uvrščamo med obnovljive vire. V teoretičnem delu magistrske naloge sta opisani sestava ter delovanje sončne celice. Bralec bo izvedel, kako sončne celice, ki generirajo enosmerno napetost, delujejo v večjih izmeničnih sistemih, ter spoznal vlogo temu namenjenih pretvornikov. V nadaljevanju je definiran izkoristek in opis vpliva naslednjih parametrov: gostota moči sončnega sevanja, temperatura sončnega modula, površina in število med seboj zaporedno in vzporedno povezanih sončnih celic ter vpadni kot sončnih žarkov. Na koncu je predstavljen še njihov vpliv na okolje. V empiričnem delu so predstavljeni rezultati meritev, ki smo jih opravili v šolskem laboratoriju. Z meritvami smo preverili pogoje, pri katerih je izkoristek sončne celice največji, vpliv različnih valovnih dolžin svetlobe ter vpliv vpadnega kota na izkoristek sončne celice. Na podlagi meritev smo pripravili osnutek poteka tehniškega dne, na katerem se učenci seznanijo z alternativnimi viri energije, med katere spadajo tudi sončne celice. V okviru tehniškega dne sta pripravljena pred test in po test za učence ter didaktična priporočila učiteljem za lažjo izvedbo tehniškega dne o sončni elektrarni. The paper focuses on the conversion of light into electricity and presents the lesson plan for a middle school technology activity day on the efficiency of solar cells. In the theoretical part of the paper, the structure and functioning of the photovoltaic cells are discussed. The first part of the paper also explains how the photovoltaic cells which generate direct current function in larger systems. In the theoretical part of the paper, also includes a chapter which analyses the function of current transducers /converters. The issue of the efficiency of photovoltaic cells and the influence of the parameters, such as: the density of solar radiation, the temperature of the photovoltaic panel, the illumination angle, the size of the surface and the number of solar cells that have parallel and serial bonds, are addressed as well in this chapter. At the end of the theoretical part, the influence of the photovoltaic cells on the environment is also presented. The empirical part of the thesis is dedicated to the analyses of the results of the measurements, which were carried out in the laboratory of the Faculty of Education, and the lesson plan for a middle school technology activity day. With the measurements, we analyzed the influence of different wavelengths of radiation and the illumination angle on the amount of the produced electricity and thus the efficiency of the photovoltaic cells under different circumstances. The results helped us to make a draft of the lesson plan for a middle school technology activity day on the efficiency of solar cells, keeping in mind that the main aim of the of the technology activity day is to inform the students about the alternative and clean sources of energy, such as solar power. The pre- and post- tests, and educational recommendations were also prepared in order to help the teachers to carry out the technology activity day on the efficiency of solar cells.

Diplomska naloga se osredotoča na praktičen primer izvedbe LED solarne razsvetljave. Gre za kompleksno področje, pri katerem si prizadevamo, z uporabo trenutno najboljše tehnologije, podaljšati avtonomijo in življenjsko dobo naše izvedbe v primerjavi z že obstoječimi rešitvami. Za dosego zgoraj omenjenega cilja smo upoštevali nekatere tehnične prilagoditve, ki so nas vodile v izdelavo LED solarne razsvetljave na osnovi ene baterijske celice LiFePo 4, in unikatnega solarnega modula, ki vključuje enostavno elektroniko in zagotavlja zanesljivost v delovanju. Dokazali smo, da je idejna zasnova izvedljiva, našo rešitev pa s tem -poleg že omenjenega- odlikujejo tudi hitra in enostavna montaža, preprosta zamenjava posameznih komponent in skupno manjši volumen ter teža. This diploma thesis deals with a practical example of the design and implementation of LED solar lighting. This involves a very complex area where we strive, with the use of the best technology currently available, to prolong the autonomy and life line of our execution in comparison with the already existing solutions. In order to achieve the abovementioned goal, we took into consideration a few technical adjustments, which led us to the Led solar lighting production on the basis of one LiFePo 4 battery cell and the unique solar module, which includes electronics and ensures reliable operation. We have proven that the whole idea of this concept is possible, however our solution –additional to that already stated- is also distinguished by quick and easy installation, easy replacement of individual components and generally less volume and weight.

Magistrsko delo obravnava problematiko optimizacije generacije čim večje količine električne energije ali zaslužka iz fotovoltaične sončne elektrarne glede na njeno postavitev. Pri postavitvi se upošteva lokacija elektrarne (zemljepisna širina), razmak med paneli in njihov naklon, saj so to dejavniki ki najbolj vplivajo na obsevanost fotovoltaičnih panelov in posledično na generacijo energije. V izdelanemu modelu lahko nastavljamo tudi velikost parcele in panela, vendar se v izračunih te vrednosti ne spreminjajo. Program izračuna senčenje panelov in upošteva manjšo generacijo energije zaradi tega. Namen programa je izračunati optimalno generacijo čim večje količine električne energije celotne elektrarne glede na parcelo, ki jo imamo na voljo. Upoštevajo se tudi stroški investicije, izračuna se letni poslovni izid. Izkaže se, da največ generirane električne energije ne pomeni nujno največji zaslužek. Bolj kot so paneli skupaj, več jih lahko postavimo na parcelo in skupaj bodo generirali največ energije, vendar bodo slabo izkoriščeni. Na zemljepisni širini 46° je optimalna postavitev, ko je razmak med paneli tri metre in naklon 28°. Bolj kot so paneli narazen, manjši je vpliv senčenja in večji je izkoristek panela. Izračuni pokažejo še, da ima senčenje panelov vpliv pa optimalni naklonski kot. Bolj kot so paneli skupaj, večji je vpliv senčenja, kar zmanjša optimalni kot. This thesis deals with finding the optimal placement of photovoltaic solar power plant in order to maximize the output of electrical energy or to maximize the profit. The latitude of the plant location, the distance between the solar panels and their angle of inclination are considered for placing the power plant. These are the variables with the biggest influence on the generation of energy. The dimensions of panels and the overall available area can also be changed in our model, but during the execution they are not changed. The model calculates self-shadowing among panels and considers lower energy output because of this. The purpose of the model is to calculate the optimal energy generation or profit of the whole power plant, depending on the available area. Cost of investment are also considered. Results show that maximum energy output does not always give the maximum profit. If the panels are closer together more of them can be installed on the available area, while consequently their output is lower because of the shading. Together they generate more energy but the profit is not maximized, furthermore even a loss might be expected. Calculations show, that shading decreases the panels’ optimal angle of the inclination the closer the panels are to each other, the smaller is the angle.

Diplomska naloga se ukvarja z načrtovanjem, pravilnim dimenzioniranjem gradnikov in modeliranjem obratovanja sončne elektrarne. V prvem, teoretičnem delu, je preko gradnikov, ki sestavljajo sončno elektrarno, opisano tudi načrtovanje s konkretnimi elementi in rešitvami, ki pripomorejo k največji uporabnosti oz. učinkovitosti samih elementov, kot tudi celotne sončne elektrarne. Drugi, programski del zajema modeliranje oz. simulacijo sončne elektrarne v okolju LabView, torej od samega začetka, ko fotonapetostna celica ob določeni jakosti sončnega sevanja odda tok, napetost in moč, do prenosa teh veličin v razsmernik. Uporabljene so numerične metode, natančneje, Newton – Raphsonova metoda. V simulaciji sta poleg modulov in razsmernika, ki so uporabljeni v načrtovanju sončne elektrarne v prejšnjih poglavjih, za medsebojno primerjavo vključena dodatna dva tipa modulov in razsmernikov ter nekaj različnih vezav modulov v fotonapetostno polje. This thesis deals with design, properly sizing of each element and modeling the operation of photovoltaic (PV) power plant. First, theoretical part of thesis describes design with concrete elements and solutions, that help enhance usability or effectivity of elements themselves, as well as the entire photovoltaic power plant. Second, software part of the thesis is based on modelling/simulation of photovoltaic power plant in LabView environment from the very beginning, when at certain intensity of incident solar irradiance solar cell transferes certain current, voltage and power to power inverter. I used numerical methods, specifically the Newton – Raphson method. For the purpose of showing and comparing different simulations, LabView program includes three different types of PV modules and power inverters and a few different interconnection schemes of PV modules in photovoltaic arrays.

Magistrsko delo obravnava vpliv temperature na optimalni položaj solarnih modulov, pri čemer upoštevamo tudi izgubo energije zaradi delovanja pogonskega sklopa. Sledenje sončnih modulov soncu omogoča večji izkoristek razpoložljive energije sončnega sevanja. Neželena posledica je segrevanje modulov ter posledično izgube zaradi segrevanja. Tako je predmet magistrskega dela določitev vpliva temperature na optimalne položaje solarnih modulov pri želenem maksimalnem izplenu pri pretvorbi energije sončnega sevanja. Pri tem upoštevamo električne izgube pogonskega sklopa. Izračuni so izvedeni za štiri dni v letu, in sicer v programskem paketu MatLab z uporabo Diferenčne evolucije. Proposed master thesis examines the impact of temperature on the optimal position of solar modules, while taking into account the losses of the electrical energy as consequences of applied tracking system. Sun-tracking solar modules represents conversion of sunlight energy into electrical energy with higher yield. On the other hand, with higher yield, the temperature of solar modules start to increase, while efficiency of the solar modules start to decrease. So, the subject of this thesis is to determine the effect of the temperature on the optimal positions of solar modules at the desired maximum yield of whole solar power plant, taking into account the electrical losses. The analysis is performed for four days within a year. Simulations were performed in program tool Matlab, with using optimization algorithm Differential evolution.

V magistrski nalogi je predstavljen matematični model fotonapetostnega sistema sestavljenega v programskem paketu Matlab/Simulink. Namen dela je najprej sestaviti matematični model sončne celice, ki je osnova za izdelavo matematičnega modela sončne elektrarne. Za ovrednotenje simulacijskih rezultatov iz matematičnega modela sončne elektrarne bomo uporabili rezultate meritev dejanske sončne elektrarne Termoelektrarne Brestanica d.o.o.. Pri tem bomo ovrednotili rezultate simulacijskih izračunov in meritev na dejanski elektrarni za različne dni letu. Rezultati kažejo dobro ujemanje med izračunanimi in izmerjenimi vrednostmi sončne elektrarne, kar je dobra osnova za nadaljno uporabo matematičnega modela sončne elektrarne. This master thesis presents a mathematical model of a photovoltaic system composed of Matlab/Simulink. Firstly, the aim of this work is to establish the mathematical model of the solar cell, which is the basis in making a mathematical model of solar power plants. For the evaluation of simulation results of the mathematical model of the solar power plant we will use the results of measurements from the actual solar power plant Termoelektrarna Brestanica d. o. o. We will evaluate the results of simulation calculations and measurements of the actual plant for different days of the year. The results show good correlation between calculated and measured values of solar power, which is a good basis for further use of mathematical model of solar power.

Cilj diplomske naloge je ugotoviti izvedljivost, izkoristek, vrednost in ekonomičnost integrirane sončne elektrarne na že obstoječem objektu. Za pridobitev večine vrednosti je bil uporabljen računalniški program PVSYST za fotovoltaične sisteme, v katerem so bile izvedene simulacije, ekonomski del pa je bil preračun na podlagi cen v letošnjem letu. Da smo prišli do vseh segmentov, ki so bili zastavljeni, smo v diplomsko delo vključili še: kratek zgodovinski pregled fotovoltaike, opis sončnega sevanja, fotonapetostnih elektraren, razsmernikov in pregled sončnih celic, ter fotonapetostnih modulov. The aim of this work was to determine the feasibility, efficiency, value and economy of integrated solar power plant on the already existing object. The computer program PVSYST for photovoltaic systems, which gives us simulations, was used to obtain most of the results, while the economic calculations were done based on this year’s prices. In order to get all the segments that had been defined in this study, we also included: a short historical overview of photovoltaics, a description of the solar radiation, photovoltaic power plants, inverters and inspection of solar cells and photovoltaic modules.

Intenzivnost vpadne sončne svetlobe in temperatura sončnih celic imata velik vpliv na izhodno napetost. Tako se izhodna napetost sončnih celic spreminja predvsem v odvisnosti od osvetlitve, ob tem pa obstaja kompleksna povezava med sončnim vzbujanjem, temperaturo in totalno upornostjo polprevodniških celic. Iz omenjenega razloga imajo sončne celice nelinearen potek izhodnega izkoristka. S sledenjem točke največje izhodne moči na karakteristiki sočnih celic lahko zagotovimo optimalno izrabo pretvorjene sončne energije. V polnilnih sistemih je lahko izhodna napetost sočnih celic posledično prenizka za izvajanje polnilnega cikla, kar vključuje potrebo po dodatnem reguliranem pretvorniku enosmernih napetosti. Predmet raziskovanja v okviru predlaganega diplomskega dela je preučiti delovanje sončnih celic in razvoj polnilnega regulatorja za samodejno optimalno polnjenje akumulatorjev pri različnih pogojih sončne aktivnosti. The intensity of the entering sun light and the temperature of solar cells have a great impact on the cell output voltage. Thus the output voltage of solar cells change primarily because of different lighting conditions, where there is a complex connection between the Sun arousal, the temperature and the total resistance of solar cells. For the reason mentioned before, the solar cells have a non linear function of efficiency. By tracking the point of the highest output power on the output characteristic of the solar cells, we can ensure the optimal use of the transformed Sun energy. In the charging systems, the output voltage of the solar cells can be consequently too low to perform the charge cycle in which case there is a need for an additional regulating transformer of DC voltages. The main goal of this diploma paper is to investigate the activity of the solar cells and the development of the charging regulator for automatic optimum charging of batteries under different conditions of the Sun activity.

Diplomsko delo obsega osnovno zgradbo sončnih elektrarn, do podrobnosti pretvornika in potrebnega filtra zanj. Pretvornik, na katerem smo delali smo dogradili z nekaterimi komponentami za zaščito in boljše delovanje. Načrtovanje filtra je sestavljeno iz načrtovanja in izbire sklopov potrebnih za izdelavo filtra za pretvornik. Za začetek je bilo potrebno določiti stopnjo filtra in zahteve za delovanje. Simulacija filtra je potekala v programskem okolju Matlab/Simulink, kjer je bilo potrebno ugotoviti, katere komponente uporabiti, da pridemo do zahtev, ki smo si jih zadali na začetku. Simulacija je sprva obsegala navadni filter, kateremu smo kasneje dodali tokovne vire na izhodu. Primeren filter smo, brez tokovnih virov, dodali na model celotnega pretvornika narejenega v Matlab/Simulinku. Kasneje smo naredili preračun izbranega filtra in primerjavo med simulacijo ter preračunom. Sledilo je načrtovanje ohišja za filter. Po izdelavi ohišja smo po zahtevah preverili pravilno delovanje filtra. Po uspešnih meritvah smo filter priključili k pretvorniku. Vse rezultate simulacij in izračunov smo prikazali v diplomski nalogi. Diploma thesis describes the basic structure of solar power to the details of the converter and the necessary filters for it. We added some components to the converter for protection and better performance. The filter design is composed of designs and choices of devices needed to build a filter for the inverter. For the start it was necessary to choose the order of filter and requirements for it. The simulation of the filter took place in Matlab / Simulink where it was necessary to determine which components should be chosen to satisfy the requirements, which were set at the beginning. The simulation model was for an ordinary filter where there was later added the current source output. Then a suitable filter with no current sources was added to the model of the entire converter made in Matlab / Simulink. Later we made the calculation of the selected filter and a comparison between simulation and calculation results. After that the filter was designed. Afterwards the building of the filter was necessary to test if it worked properly as required. After the successful measurements of the filter it was connected to the inverter. All the results of simulations and calculations are given.

Diplomsko naloga opisuje sončne celice, fotonapetostne module in na kratko opisuje tudi ostale elemente fotonapetostnega sistema. Osredotočili smo se predvsem na obnašanje fotonapetostnih modulov pri danih pogojih sončnega sevanja. Rezultat diplomske naloge je posamezna predstavitev in medsebojna primerjava karakteristik najpogosteje uporabljanih fotonapetostnih modulov v praksi. To so moduli iz polikristalnega, monokristalnega in amorfnega silicija. V delu so predstavljeni tudi standardi in predpisi s področja fotonapetostnih sistemov. Diploma thesis describes the solar cells, photovoltaic modules and also briefly describes the other elements of photovoltaic system. It focuses mainly on the behavior of photovoltaic modules in given conditions of solar irradiance. The result of diploma thesis is individual presentation and comparison of characteristics of photovoltaic modules most commonly used in practice. These are the modules of polycrystalline, monocrystalline and amorphous silicon. In this paper are also presented the standards and regulations regarding photovoltaic systems.