The proper designing of PV systems requires the use of advanced building energy simulation techniques. It allows to design the best position of the PV array, as well as the right quantity of produced energy in different cases. On the other hand the PV efficiency is not only a constant value but changes according to temperature and solar radiation. This paper is devoted to estimate the simultaneous effect of both weather factors on PV efficiency. The task was achieved by numerical simulation and ESP-r software. Computer simulations have been carried out with the use of the Typical Meteorological Year data for Warsaw (52°N 21°E). The greatest influence of temperature on the efficiency of solar energy conversion was observed for crystalline silicon cells. The influence of the boundary conditions assumed in the study is ignored for amorphous silicon cells in the summer period and regardless of the material type in the winter period.
This article considers designing of a renewable electrical power generation system for self-contained homes away from conventional grids. A model based on a technique for the analysis and evaluation of two solar and wind energy sources, electrochemical storage and charging of a housing area is introduced into a simulation and calculation program that aims to decide, based on the optimized results, on electrical energy production system coupled or separated from the two sources mentioned above that must be able to ensure a continuous energy balance at any time of the day. Such system is the most cost-effective among the systems found. The wind system adopted in the study is of the low starting speed that meets the criteria of low winds in the selected region under study unlike the adequate solar resource, which will lead to an examination of its feasibility and profitability to compensate for the inactivity of photovoltaic panels in periods of no sunlight. That is a system with fewer photovoltaic panels and storage batteries whereby these should return a full day of autonomy. Two configurations are selected and discussed. The first is composed of photovoltaic panels and storage batteries and the other includes the addition of a wind system in combination with the photovoltaic system with storage but at a higher investment cost than the first. Consequently, this result proves that is preferable to opt for a purely photovoltaic system supported by the storage in this type of site and invalidates the interest of adding micro wind turbines adapted to sites with low wind resources.
In this work, two thermal- and air-stable, hole transporting materials (HTM) in perovskite solar cells are analyzed. Those obtained and investigated materials were two polyazomethines: the first one with three thiophene rings and 3,3′-dimethoxybenzidine moieties (S9) and the second one with three thiophene rings and fluorene moieties (S7). Furthermore, presented polyazomethines were characterized by Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, atomic force microscopy (AFM) and thermogravimetric analysis (TGA) experiments. Both polyazomethines (S7 and S9) possessed good thermal stability with a 5% weight loss at 406 and 377°C, respectively. The conductivity of S7 was two orders of magnitude higher than for S9 polymer (2.7 × 10−8 S/cm, and 2.6 × 10−10 S/cm, respectively). Moreover, polyazomethine S9 exhibited 31 nm bathochromic shift of the absorption band maximum compared to S7.
Obtained perovskite was investigated by UV–vis and XRD. Electrical parameters of perovskite solar cells (PSC) were investigated at Standard Test Conditions (STC). It was found that both polyazomethines protect perovskite which is confirmed by ageing test where Voc did not decrease significantly for solar cells with HTM in contrast to solar cell without hole conductor, where Voc decrease was substantial. The best photoconversion efficiency (PCE = 6.9%), among two investigated in this work polyazomethines, was obtained for device with the following architectures FTO/TiO2/TiO2 + perovskite/S7/Au. Stability test proved the procreative effects of polyazomethines on perovskite absorber.
In this paper, dynamic response improvement of the grid connected hybrid system comprising of the wind power generation system (WPGS) and the photovoltaic (PV) are investigated under some critical circumstances. In order to maximize the output of solar arrays, a maximum power point tracking (MPPT) technique is presented. In this paper, an intelligent control technique using the artificial neural network (ANN) and the genetic algorithm (GA) are proposed to control the MPPT for a PV system under varying irradiation and temperature conditions. The ANN-GA control method is compared with the perturb and observe (P&O), the incremental conductance (IC) and the fuzzy logic methods. In other words, the data is optimized by GA and then, these optimum values are used in ANN. The results are indicated the ANN-GA is better and more reliable method in comparison with the conventional algorithms. The allocation of a pitch angle strategy based on the fuzzy logic controller (FLC) and comparison with conventional PI controller in high rated wind speed areas are carried out. Moreover, the pitch angle based on FLC with the wind speed and active power as the inputs can have faster response that lead to smoother power curves, improving the dynamic performance of the wind turbine and prevent the mechanical fatigues of the generator.
Fast and accurate grid signal frequency estimation is a very important issue in the control of renewable energy systems. Important factors that influence the estimation accuracy include the A/D converter parameters in the inverter control system. This paper presents the influence of the number of A/D converter bits b, the phase shift of the grid signal relative to the time window, the width of the time window relative to the grid signal period (expressed as a cycle in range (CiR) parameter) and the number of N samples obtained in this window with the A/D converter on the developed estimation method results. An increase in the number b by 8 decreases the estimation error by approximately 256 times. The largest estimation error occurs when the signal module maximum is in the time window center (for small values of CiR) or when the signal value is zero in the time window center (for large values of CiR). In practical applications, the dominant component of the frequency estimation error is the error caused by the quantization noise, and its range is from approximately 8×10-10 to 6×10-4.
A sliding mode controller for the photovoltaic pumping system has been proposed in this paper. This system is composed of a photovoltaic generator supplying a three-phase permanent magnet synchronous motor coupled to a centrifugal pump through a three-phase voltage inverter. The objective of this study is to minimise the number of regulators and apply the sliding mode control by exploiting the specification of the field oriented control scheme (FOC). The first regulator is used to force the photovoltaic generator to operate at the maximum power point, while the second is used to provide the field oriented control to improve the system performance.The whole system is analysed and its mathematical model is done. Matlab is used to validate the performance and robustness of the proposed control strategy.
An integrated Z-source inverter for the single-phase single-stage grid-connected photovoltaic system is proposed in this paper. The inverter integrates three functional blocks including maximum-power-point-tracking, step-up/down DC-side voltage and output grid-connected current. According to the non-minimum-phase characteristic presented in DC-side and the functional demands of the system, two constant-frequency sliding-mode controllers with integral compensation are proposed to guarantee the system robustness. By using two controllers, the effects caused by the non-minimum-phase characteristic are mitigated. Under the circumstance of that the input voltage or the grid-connected current changes suddenly, the notches/protrusions following the over-shoot/ under-shoot of the DC-bus voltage are eliminated. The quality of grid-connected current is ensured. Also, a small-signal modelling method is employed to analyze the close-loop system. A 300W prototype is built in the laboratory. A solar-array simulator (SAS) is used to verify the systematic responses in the experiment. The correctness and validity of the inverter and proposed control algorithm are proved by simulation and experimental results.
Efektywność energetyczna modułów fotowoltaicznych stanowi jeden z najważniejszych aspektów przekładających się na sferę ekonomiczną przedsięwzięcia związanego z instalacją modułów fotowoltaicznych. Na efektywność modułów i wielkość energii elektrycznej produkowaną na drodze konwersji fotowoltaicznej w modułach fotowoltaicznych ma wpływ wiele czynników zarówno wewnętrznych, związanych z samą budową modułu i jego parametrami technicznymi, jak i zewnętrznych, związanych z infrastrukturą energetyczną, w skład której wchodzi okablowanie i inwertery, oraz z warunkami klimatycznymi panującymi w miejscu lokalizacji instalacji energetycznej i usytuowania modułów związanych z orientacją oraz kątem nachylenia modułów fotowoltaicznych. Instalacja modułów fotowoltaicznych powinna być poprzedzana i uwarunkowana wykonaniem analiz szacujących ilość wytworzonej energii, a więc analiz produkcji energii elektrycznej, które to pomogą wskazać optymalne rozwiązanie dostosowane do danych warunków. W artykule przedstawiono analizę porównawczą wielkości wytwarzanej energii w warunkach rzeczywistych oraz symulowanych. Analiz dokonano na podstawie badań przeprowadzonych w Laboratorium Monitoringu Energii Wiatrowej i Słonecznej AGH, danych z baz nasłonecznienia oraz oprogramowania komputerowego do szacowania zasobów energetycznych. Badaniu poddano korelację natężenia promieniowania słonecznego padającego na moduł fotowoltaiczny oraz mocy uzyskanej przez moduł. Porównano ilość wytworzonej przez moduł energii elektrycznej w warunkach rzeczywistych oraz symulowanych z dwóch źródeł. Dokonano także porównania i analizy ilości wyprodukowanej energii modułu z uwzględnieniem symulowanych różnych kątów jego nachylenia.
W referacie przedstawiono wyniki analizy efektywności przetwarzania energii promieniowania słonecznego na energię elektryczną w warunkach polskich. Pokazano wpływ nasłonecznienia i temperatury pracy modułu fotowoltaicznego na jego krzywą mocy P = f(U). Opisano warunki dla których producenci podają parametry modułów fotowoltaicznych i skonfrontowano je z warunkami rzeczywistymi panującymi w Polsce. Zwrócono uwagę na konieczność podawania przez producentów paneli fotowoltaicznych charakterystyk PPV = f(E) dla różnych wartości temperatury pracy modułów. Przeprowadzono analizę ekonomicznej efektywności inwestycji farmy fotowoltaicznej o mocy 1 MWp z uwzględnieniem aktualnych przepisów prawa dla trzech wariantów. Wariant I – inwestor korzysta ze środków wsparcia pomocy publicznej tylko o charakterze operacyjnym, wariant II – inwestor korzysta ze środków wsparcia pomocy publicznej o charakterze inwestycyjnym w wysokości 1 mln PLN, wariant III – inwestor korzysta ze środków wsparcia pomocy publicznej o charakterze inwestycyjnym w wysokości 2 mln PLN. Dla wszystkich wariantów wyznaczono wskaźniki oceny ekonomicznej efektywności inwestycji oraz wartości cen aukcyjnych od ceny maksymalnej do ceny przy której projekt traci rentowność.
Photovoltaic (PV) technologies which play a role in PV market are divided into basic two types: wafer-based (1st generation PV) and thin-film cell (2nd generation PV). To the first category belong mainly crystalline silicon (c-Si) cells (both mono- and multi-crystalline). In 2015 around 90% of the solar market belonged to crystalline silicon. To the 2nd generation solar cells belongs thin film amorphous silicon (a-Si) or a combination of amorphous and microcrystalline silicon (a-Si/μc-Si), compound semiconductor cadmium telluride (CdTe), compound semiconductor made of copper, indium, gallium and selenium (CIS or CIGS) and III–V materials. The PV market for thin film technology is dominated by CdTe and CIGS solar cells. Thin film solar cells’ share for all thin film technologies was only 10% in 2015. New emerging technologies, called 3rd generation solar cells, remain the subject of extensive R&D studies but have not been used in the PV market, so far.
In this review the best laboratory 1st and 2nd generation solar cells that were recently achieved are described. The scheme of the layer structure and energy band diagrams will be analyzed in order to explain the boost of their efficiency with reference to the earlier standard designs.