The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability

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The subject of this master’s thesis is to introduce concentrator photovoltaic systems. Main subject of presented work are photovoltaic cells and their features and characteristics. The work deals with physical fundamentals of solar cells, type of cells and their specifics and discusses possible treatment for achieving better characteristics of concentrator systems. In the practical part is realized measurement and analysis of electrical characteristics of 9 different monocrystalline silicon cells. From those is the most efficient cell chosen for further use as reference cell.

The diploma thesis is focused on the evaluation of a photovoltaic power plant in the company premises. The first chapters briefly discuss the theory of electricity generation using photovoltaic panels. It describes the principle of operation of photovoltaic panels, history, production, etc. In the practical part of the thesis we focus on the evaluation of the company's photovoltaic power plant when comparing real data with simulations.

This diploma thesis is focused on the assessment of the possibilities of disposal of photovoltaic panels installed in the Czech Republic. In addition to the basic theory of photovoltaic cells and panels, the theoretical parts describe legislation, subsidies in the field of photovoltaics and the development of photovoltaics in the Czech Republic. As part of recycling, their methods, work with the collective system, as well as the impact on the environment are analyzed. In the experimental part, using the data of the installed capacity and the average weights of the panels, various projections of the disposal of the panels over time are made, which take into account factors such as the life of the power plant or the capacity of the recycling line. Furthermore, according to the available literature, an analysis of the revenue from the sale of recycled materials contained in panels installed in our territory is performed. Subsequently, the needs of future implementers of proven estimates of labor and logical demands were assessed. Finally, an economic evaluation of the fundamental aspects of the FRELP recycling process was performed and the net prices of different recycling directions were determined.

The presented thesis is concerned with the principles of Photovoltaics. It describes the basic principles of photovoltaic panels functioning and the unique periods of their developement. The thesis is also focused on the theoretical knowledge of equivalent circuits of photovoltaic panels. The primary objective of the thesis is a project of simulation environment in the programme Agilent VEE Pro 8.0. The programme enables a simulation of I-U characteristics of real photovoltaic panels.

This thesis deals with usage of bypass diodes in photovoltaic panels. Familiarize us with principles of photovoltaic modules and functions, their electrical characteristics and features. The central objective of this work is description of influence of bypass diodes on particularly shading photovoltaic panels and its volt-ampere characteristics. By the help of created software in Agilent VEE 8.0 simulate the shading panel and compare with real measurement.

The beginning of this work presents the basic principles of photovoltaic cells, their advantages and disadvantages. There is also an overview of photovoltaic systems. The next part takes a closer look on lead-acid accumulators followed by a practical part regarding the measurement of VA characteristics. The main goal of this work is to assemble an experimental PV system. It will consist of a PV module, an accumulator (consisting of two cells connected in series and producing an overall voltage of 5V) and of a variable load (assembled from nineteen resistors with resistance varying from tens to hundreds of Ohms). This system is connected to a computer that runs the control software which was created using the VEEPro 8.0 simulation environment. The measurements can be taken in two ways. Either the operator can select the load resistor combinations manually, or the operator only launches the measurement and the load is selected automatically by the software. This way we obtain an automatized workplace for measuring VA characteristics of photovoltaic panels.

The output of our work is complete proposal of the building wiring, the photovoltaic power plant proposal and technical report. In the first part we find the theoretical information concerning the proposal of the house wiring, explanations of basic terms and principles of technical documentation. We can find also an overview of known intelligent systems and a brief description. In the second part we describe itself proposal of concrete building, step by step. We can find a description of a created program to control building. The third part is focused on theoretical information about photovoltaics. Here we explain the basic principle, the limits of technology, materials and the panel structure. In the fourth part we proceeded to the actual plant proposal. Here we find the principle and a block diagram of system and description of the components of the plant, evaluation of production and energy consumption. Drawings of the technical documentation wiring as a photovoltaic power plant, distributor scheme and its layout can be found in the technical report, in Attachment.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.