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In this research paper, a nonlinear autoregressive with exogenous input (NARX) model of the nonlinear system based on neural network and time series analysis is proposed to deal with the one-month forecast of the produced power from photovoltaic modules (PVM). The PVM is a monocrystalline cell with a rated production of 175 watts that is placed at Heliopolis University, Bilbéis city, Egypt. The NARX model is considered powerful enough to emulate the nonlinear dynamic state-space model. It is extensively performed to resolve a variety of problems and is mainly important in complex process control. Moreover, the NARX method is selected because of its quick learning and completion times, as well as high appropriateness, and is distinguished by advantageous dynamics and interference resistance. The neural network (NN) is trained and optimized with three algorithms, the Levenberg–Marquardt Algorithm (NARX-LMA), the Bayesian Regularization Algorithm (NARX-BRA) and the Scaled Conjugate Gradient Algorithm (NARX-SCGA), to attain the best performance. The forecasted results using the NARX method based on the three algorithms are compared with experimentally measured data. The NARX-LMA, NARX-BRA and NARX-SCGA models are validated using statistical criteria. In general, weather conditions have a significant impact on the execution and quality of the results.
Mohamed Louzazni; Heba Mosalam; Daniel Tudor Cotfas. Forecasting of Photovoltaic Power by Means of Non-Linear Auto-Regressive Exogenous Artificial Neural Network and Time Series Analysis. Electronics 2021, 10, 1953 .
AMA StyleMohamed Louzazni, Heba Mosalam, Daniel Tudor Cotfas. Forecasting of Photovoltaic Power by Means of Non-Linear Auto-Regressive Exogenous Artificial Neural Network and Time Series Analysis. Electronics. 2021; 10 (16):1953.
Chicago/Turabian StyleMohamed Louzazni; Heba Mosalam; Daniel Tudor Cotfas. 2021. "Forecasting of Photovoltaic Power by Means of Non-Linear Auto-Regressive Exogenous Artificial Neural Network and Time Series Analysis." Electronics 10, no. 16: 1953.
This paper presents a new hybrid successive discretisation algorithm, used to calculate the parameters of the photovoltaic cells and panels, by the one diode model and the two diode model. Nine known datasets from the specialised literature were used to validate the new algorithm and then it was firstly applied for two new datasets. For the first time only one algorithm is applied to extract the parameters, in both cases—one and two diode models. The new datasets are for commercial monocrystalline silicon and amorphous silicon photovoltaic cells. The main test used to prove the performance of HDSA is the root mean square error. Other four tests were used for comparison: the mean absolute error, the mean bias error, t-statistic, and the coefficient of determination. The hybrid successive discretisation algorithm proved its accuracy and reliability for parameter extraction of different types of photovoltaic cells and panels for all datasets used. Comparing the hybrid successive discretisation algorithm with the best algorithms from the specialised literature shows an improvement of the root mean square error by up to10.4% for the one diode model and by up to 7.5% for the two diode model, respectively.
Daniel T. Cotfas; Adrian M. Deaconu; Petru A. Cotfas. Hybrid successive discretisation algorithm used to calculate parameters of the photovoltaic cells and panels for existing datasets. IET Renewable Power Generation 2021, 1 .
AMA StyleDaniel T. Cotfas, Adrian M. Deaconu, Petru A. Cotfas. Hybrid successive discretisation algorithm used to calculate parameters of the photovoltaic cells and panels for existing datasets. IET Renewable Power Generation. 2021; ():1.
Chicago/Turabian StyleDaniel T. Cotfas; Adrian M. Deaconu; Petru A. Cotfas. 2021. "Hybrid successive discretisation algorithm used to calculate parameters of the photovoltaic cells and panels for existing datasets." IET Renewable Power Generation , no. : 1.
The solar energy is increasingly used as a renewable energy source. Raising the efficiency of energy conversion from solar to useful energy (electric and thermal) represents an important research direction in the renewable energy domain. Using hybrid systems for electric and thermal energy cogeneration can be a solution. In this study, a hybrid system (HS) is designed, manufactured, implemented, and experimentally tested under concentrated sunlight with a concentration ratio of 25 suns, obtained using a Fresnel lens as a sunlight concentrator. The HS comprises of four concentrated photovoltaic cells (CPVs), four thermoelectric generators (TEGs), and a solar thermal collector (STC). The HS is studied in three configurations of the exposed surface: only the CPV active area, the CPV active area with ceramic support, and the CPV active area with ceramic support covered with graphite sheet. Results reveal that the efficiency of each system component is affected by the exposed surface. If the efficiencies of the CPVs decrease from 32.3% to 30.8% from the first configuration to the last one, the efficiencies of TEGs and STC increase from 0.12% to 0.44 and from 26.3% to 52.0%, respectively. Increasing the concentration ratio from 25 to 33 suns, the power of the CPVs increases with almost 31%, but the efficiency decreases slightly, instead the efficiencies of the TEGs and STC increase.
Petru A. Cotfas; Daniel T. Cotfas. Solar Hybrid System Component Study in Low Concentrated Sunlight. International Journal of Photoenergy 2021, 2021, 1 -13.
AMA StylePetru A. Cotfas, Daniel T. Cotfas. Solar Hybrid System Component Study in Low Concentrated Sunlight. International Journal of Photoenergy. 2021; 2021 ():1-13.
Chicago/Turabian StylePetru A. Cotfas; Daniel T. Cotfas. 2021. "Solar Hybrid System Component Study in Low Concentrated Sunlight." International Journal of Photoenergy 2021, no. : 1-13.
Some parameters must be calculated with very good accuracy for the purpose of designing, simulating, and evaluating the performance of a photovoltaic system. The seven parameters of the photovoltaic cell and panels for the two-diode model are determined using a parallelized metaheuristic algorithm based on successive discretization. The parameters obtained for a photovoltaic cell and four panels using the proposed algorithm are compared with the ones calculated through over twenty methods from recent research literature. The root mean square error is used to prove the superiority of the Parallelized Successive Discretization Algorithm (PSDA). The smallest values for root mean square error (RMSE) in both cases, photovoltaic cell and panels, are obtained for the algorithm presented in this paper. The seven parameters for three panels known in the specialised literature, Kyocera KC200GT, Leibold Solar Module LSM 20, and Leybold Solar Module STE 4/100 are determined for the first time using PSDA.
Adrian M. Deaconu; Daniel T. Cotfas; Petru A. Cotfas. Calculation of Seven Photovoltaic Cells Parameters Using Parallelized Successive Discretization Algorithm. International Journal of Photoenergy 2020, 2020, 1 -13.
AMA StyleAdrian M. Deaconu, Daniel T. Cotfas, Petru A. Cotfas. Calculation of Seven Photovoltaic Cells Parameters Using Parallelized Successive Discretization Algorithm. International Journal of Photoenergy. 2020; 2020 ():1-13.
Chicago/Turabian StyleAdrian M. Deaconu; Daniel T. Cotfas; Petru A. Cotfas. 2020. "Calculation of Seven Photovoltaic Cells Parameters Using Parallelized Successive Discretization Algorithm." International Journal of Photoenergy 2020, no. : 1-13.
Finding new sustainable energy sources or improving the efficiencies of the existing ones represents a very important research and development direction. The hybridization approach is one solution for increasing the efficiency of the existing energy sources. In the case of photovoltaic technology, the hybridization of the photovoltaic panels (PV) with thermoelectric generators (TEGs) has become a more interesting solution for the research community in the last decade. Thus, a comprehensive review of the characterization methods and instruments used in PV-TEG hybrid system study represents the objective of this work. PV and TEG equivalent circuits are presented. The instruments and software applications used for the measurements and simulations are presented and analyzed. The analysis of the literature reveals that there are many papers that offer partial or no information about the instruments used or about the measurement quality (accuracies, uncertainties, etc.). In hybrid system modeling, the preferred software applications are MATLAB (MathWorks, Natick, MA, USA) and COMSOL Multiphysics (Comsol, Burlington, MA, USA), while for experimental studies based on computers, LabVIEW (NI, Austin, TX, USA) is preferred. This review work could be interesting for researchers and engineers who are interested in finding solutions for characterizing or monitoring hybrid system components, but it is not limited to these.
Petru Adrian Cotfas; Daniel Tudor Cotfas. Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization. Energies 2020, 13, 6045 .
AMA StylePetru Adrian Cotfas, Daniel Tudor Cotfas. Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization. Energies. 2020; 13 (22):6045.
Chicago/Turabian StylePetru Adrian Cotfas; Daniel Tudor Cotfas. 2020. "Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization." Energies 13, no. 22: 6045.
This paper introduces the management control of a microgrid comprising of photovoltaic panels, battery, supercapacitor, and DC load under variable solar irradiation. The battery is used to store the energy from the photovoltaic panels or to supply the load. The supercapacitor is used to reduce stress on batteries, improve their life cycle, and absorb the fluctuations in the energy produced. The generated photovoltaic power is optimized using Perturb and Observe and Incremental Conductance algorithms to extract the maximum power point tracking. The two algorithms are modified by adding an instantaneous step size to change the direction of the power, so as to reach the maximum power point tracking. The currents of the battery and supercapacitor are managed and controlled using the multi-loop proportional integral controllers. The obtained results show that the multi-loop proportionally integral controllers Perturb and Observe are better than the multi-loop proportional integral controllers Incremental Conductance in terms of stability of injected power. The storage system works perfectly for energy supply, system protection, and fluctuation absorption during the transitions in the solar irradiation. The proposed hybrid storage system can be installed in rural areas as an off-grid system for several uses.
Mohamed Louzazni; Daniel Tudor Cotfas; Petru Adrian Cotfas. Management and Performance Control Analysis of Hybrid Photovoltaic Energy Storage System under Variable Solar Irradiation. Energies 2020, 13, 1 .
AMA StyleMohamed Louzazni, Daniel Tudor Cotfas, Petru Adrian Cotfas. Management and Performance Control Analysis of Hybrid Photovoltaic Energy Storage System under Variable Solar Irradiation. Energies. 2020; 13 (12):1.
Chicago/Turabian StyleMohamed Louzazni; Daniel Tudor Cotfas; Petru Adrian Cotfas. 2020. "Management and Performance Control Analysis of Hybrid Photovoltaic Energy Storage System under Variable Solar Irradiation." Energies 13, no. 12: 1.
Daniel T. Cotfas; Dezso Sera; Eleni Kaplani; Petru A. Cotfas; Alireza Rezaniakolaei. Advancements in Photovoltaic Cell and System Technologies. International Journal of Photoenergy 2019, 2019, 1 -2.
AMA StyleDaniel T. Cotfas, Dezso Sera, Eleni Kaplani, Petru A. Cotfas, Alireza Rezaniakolaei. Advancements in Photovoltaic Cell and System Technologies. International Journal of Photoenergy. 2019; 2019 ():1-2.
Chicago/Turabian StyleDaniel T. Cotfas; Dezso Sera; Eleni Kaplani; Petru A. Cotfas; Alireza Rezaniakolaei. 2019. "Advancements in Photovoltaic Cell and System Technologies." International Journal of Photoenergy 2019, no. : 1-2.
The main goal of this paper is to review the most important methods previously developed to enhance the efficiency and increase the lifetime of photovoltaic panels. The methods to increase the solar radiation incident on photovoltaic panels, as well as the cooling and the maximum power point tracker methods, are concisely presented in this paper. The pros and cons analysis reveals that the methods to enhance the power generated by the photovoltaic panels are strongly dependent on geographical location, climatic conditions, and the materials used. This review paper is also of interest for engineers who attempt to identify the most adequate solutions to maximize the energy output of photovoltaic systems for each location.
D. T. Cotfas; P. A. Cotfas. Multiconcept Methods to Enhance Photovoltaic System Efficiency. International Journal of Photoenergy 2019, 2019, 1 -14.
AMA StyleD. T. Cotfas, P. A. Cotfas. Multiconcept Methods to Enhance Photovoltaic System Efficiency. International Journal of Photoenergy. 2019; 2019 ():1-14.
Chicago/Turabian StyleD. T. Cotfas; P. A. Cotfas. 2019. "Multiconcept Methods to Enhance Photovoltaic System Efficiency." International Journal of Photoenergy 2019, no. : 1-14.
Photovoltaic (PV) panels are used for both standalone applications and grid-connected systems. In the former case, the PV panels used vary in size, from very small, for smart solar garden lamps, to standard, in order to ensure the necessary electric energy for a house. For these cases, it is very important to choose the best solution in terms of photovoltaic cell materials. In this paper, a comparative study of two commercial photovoltaic panels, monocrystalline and amorphous silicon, is presented. The two photovoltaic panels are measured in natural conditions, during two years, in Brasov, Romania. The emphasis is placed upon the maximum power generated by the two panels, but the cost and the lifetime are also taken into consideration. The gain in average maximum power for the monocrystalline silicon panel varies from 1.9 times for low irradiance to 2.4 times higher than the one obtained from the amorphous silicon panel, during the test period. The temperature of the monocrystalline silicon panels is lower than that of the amorphous silicon panel in the majority of measurements. The degradation rate determined in two years is 1.02% for the monocrystalline silicon panel and 1.97% for the amorphous silicon panel.
Daniel T. Cotfas; Petru A. Cotfas. Comparative Study of Two Commercial Photovoltaic Panels under Natural Sunlight Conditions. International Journal of Photoenergy 2019, 2019, 1 -10.
AMA StyleDaniel T. Cotfas, Petru A. Cotfas. Comparative Study of Two Commercial Photovoltaic Panels under Natural Sunlight Conditions. International Journal of Photoenergy. 2019; 2019 ():1-10.
Chicago/Turabian StyleDaniel T. Cotfas; Petru A. Cotfas. 2019. "Comparative Study of Two Commercial Photovoltaic Panels under Natural Sunlight Conditions." International Journal of Photoenergy 2019, no. : 1-10.
The development in the field of semiconductor materials and electronic devices has a great impact on systems with renewable energy sources. Determination of the functional parameters of photovoltaic solar cells is essential for the subsequent usage of these semiconductor devices. Research was made on type P+PNN+ monocrystalline silicon wafers. Crystallographic measurements of the photovoltaic solar cell were made by means of FESEM-FIB Auriga Workstation. Initial data were selected from the study of models found in the specialized literature. The experimental results were compared to classical mathematical models. Measurements made on the photovoltaic solar cell were realised in laboratory conditions on the NI-ELVIS platform produced by National Instruments.
Cristian-Petre Fluieraru; Gabriel Predușcă; Horia Andrei; Emil Diaconu; Petru Adrian Cotfas; Daniel Tudor Cotfas. Determination of Technological Features of a Solar Photovoltaic Cell Made of Monocrystalline Silicon P+PNN+. International Journal of Photoenergy 2019, 2019, 1 -14.
AMA StyleCristian-Petre Fluieraru, Gabriel Predușcă, Horia Andrei, Emil Diaconu, Petru Adrian Cotfas, Daniel Tudor Cotfas. Determination of Technological Features of a Solar Photovoltaic Cell Made of Monocrystalline Silicon P+PNN+. International Journal of Photoenergy. 2019; 2019 ():1-14.
Chicago/Turabian StyleCristian-Petre Fluieraru; Gabriel Predușcă; Horia Andrei; Emil Diaconu; Petru Adrian Cotfas; Daniel Tudor Cotfas. 2019. "Determination of Technological Features of a Solar Photovoltaic Cell Made of Monocrystalline Silicon P+PNN+." International Journal of Photoenergy 2019, no. : 1-14.
The extraction of the photovoltaic cells and panels parameters still represents a hot topic, despite the numerous methods proposed by researchers in scientific literature. In order to optimize the efficiency of photovoltaic cells and panels and to predict the energy they generate, it is useful to accurately calculate their parameters function of temperature and irradiance. This paper proposes the Successive discretization algorithm developed to extract five parameters of photovoltaic cells and panels using the current voltage characteristic and the one diode model. Three widely used standard datasets, one for the photovoltaic cell and two for photovoltaic panels, are utilized. Other three datasets are analyzed, one measured in laboratory conditions for the monocrystalline photovoltaic cell and two under natural sunlight for the monocrystalline photovoltaic panel. The proposed algorithm proves its performance through comparison with other over twenty accepted methods used in specialized literature. The comparison is made for five parameters and the root mean square error. The obtained results demonstrate that the method presented is one of the best and it increases the determination accuracy of important photovoltaic cells’ parameters. Thus, the Successive discretization algorithm is a very good candidate as tool for extracting the photovoltaic cells and panels parameters.
Daniel T. Cotfas; Adrian M. Deaconu; Petru A. Cotfas. Application of successive discretization algorithm for determining photovoltaic cells parameters. Energy Conversion and Management 2019, 196, 545 -556.
AMA StyleDaniel T. Cotfas, Adrian M. Deaconu, Petru A. Cotfas. Application of successive discretization algorithm for determining photovoltaic cells parameters. Energy Conversion and Management. 2019; 196 ():545-556.
Chicago/Turabian StyleDaniel T. Cotfas; Adrian M. Deaconu; Petru A. Cotfas. 2019. "Application of successive discretization algorithm for determining photovoltaic cells parameters." Energy Conversion and Management 196, no. : 545-556.
The temperature is one of the most important factors which affect the performance of the photovoltaic cells and panels along with the irradiance. The current voltage characteristics, I-V, are measured at different temperatures from 25°C to 87°C and at different illumination levels from 400 to 1000 W/m2, because there are locations where the upper limit of the photovoltaic cells working temperature exceeds 80°C. This study reports the influence of the temperature and the irradiance on the important parameters of four commercial photovoltaic cell types: monocrystalline silicon—mSi, polycrystalline silicon—pSi, amorphous silicon—aSi, and multijunction InGaP/InGaAs/Ge (Emcore). The absolute and normalized temperature coefficients are determined and compared with their values from the related literature. The variation of the absolute temperature coefficient function of the irradiance and its significance to accurately determine the important parameters of the photovoltaic cells are also presented. The analysis is made on different types of photovoltaics cells in order to understand the effects of technology on temperature coefficients. The comparison between the open-circuit voltage and short-circuit current was also performed, calculated using the temperature coefficients, determined, and measured, in various conditions. The measurements are realized using the SolarLab system, and the photovoltaic cell parameters are determined and compared using the LabVIEW software created for SolarLab system.
Daniel Tudor Cotfas; Petru Adrian Cotfas; Octavian Mihai Machidon. Study of Temperature Coefficients for Parameters of Photovoltaic Cells. International Journal of Photoenergy 2018, 2018, 1 -12.
AMA StyleDaniel Tudor Cotfas, Petru Adrian Cotfas, Octavian Mihai Machidon. Study of Temperature Coefficients for Parameters of Photovoltaic Cells. International Journal of Photoenergy. 2018; 2018 ():1-12.
Chicago/Turabian StyleDaniel Tudor Cotfas; Petru Adrian Cotfas; Octavian Mihai Machidon. 2018. "Study of Temperature Coefficients for Parameters of Photovoltaic Cells." International Journal of Photoenergy 2018, no. : 1-12.
The capacitance is one of the key dynamic parameters of solar cells, which can provide essential information regarding the quality and health state of the cell. However, the measurement of this parameter is not a trivial task, as it typically requires high accuracy instruments using, e.g., electrical impedance spectroscopy (IS). This paper introduces a simple and effective method to determine the electric capacitance of the solar cells. An RLC (Resistor Inductance Capacitor) circuit is formed by using an inductor as a load for the solar cell. The capacitance of the solar cell is found by measuring the frequency of the damped oscillation that occurs at the moment of connecting the inductor to the solar cell. The study is performed through simulation based on National Instruments (NI) Multisim application as SPICE simulation software and through experimental capacitance measurements of a monocrystalline silicon commercial solar cell and a photovoltaic panel using the proposed method. The results were validated using impedance spectroscopy. The differences between the capacitance values obtained by the two methods are of 1% for the solar cells and of 9.6% for the PV panel. The irradiance level effect upon the solar cell capacitance was studied obtaining an increase in the capacitance in function of the irradiance. By connecting different inductors to the solar cell, the frequency effect upon the solar cell capacitance was studied noticing a very small decrease in the capacitance with the frequency. Additionally, the temperature effect over the solar cell capacitance was studied achieving an increase in capacitance with temperature.
Petru Adrian Cotfas; Daniel Tudor Cotfas; Paul Nicolae Borza; Dezso Sera; Remus Teodorescu. Solar Cell Capacitance Determination Based on an RLC Resonant Circuit. Energies 2018, 11, 672 .
AMA StylePetru Adrian Cotfas, Daniel Tudor Cotfas, Paul Nicolae Borza, Dezso Sera, Remus Teodorescu. Solar Cell Capacitance Determination Based on an RLC Resonant Circuit. Energies. 2018; 11 (3):672.
Chicago/Turabian StylePetru Adrian Cotfas; Daniel Tudor Cotfas; Paul Nicolae Borza; Dezso Sera; Remus Teodorescu. 2018. "Solar Cell Capacitance Determination Based on an RLC Resonant Circuit." Energies 11, no. 3: 672.
Two new hybrid systems incorporating photovoltaic, thermoelectric, and solar collector components were designed and characterized under natural sunlight conditions. Two types of photovoltaic cells were used: monocrystalline silicon and polycrystalline silicon connected on the hot side of the thermoelectric generator. The two types of solar collectors used were connected on the cold side of the thermoelectric generator. The experimental setup is presented in this paper. The behavior of each component related to irradiance, temperature, and wind speed was studied. The performances of the hybrid systems were determined and compared. The best performance was observed for the hybrid system with the monocrystalline photovoltaic panel. The maximum power of the photovoltaic cells increased by more than 11% when they were integrated in a hybrid system, due to a decrease in temperature. The photovoltaic cells’ temperature decreased by 6°C for the solar radiation of 440 W/m2, to 19°C for 1,000 W/m2. The time stabilization was determined at 7–8 min for both hybrid systems in clear sky conditions. The software for the system control, data acquisition, and determination of the components’ parameters was developed using a graphical language program.
Daniel Tudor Cotfas; Petru Adrian Cotfas; Daniela Ciobanu; Octavian Mihai Machidon. Characterization of Photovoltaic–Thermoelectric–Solar Collector Hybrid Systems in Natural Sunlight Conditions. Journal of Energy Engineering 2017, 143, 04017055 .
AMA StyleDaniel Tudor Cotfas, Petru Adrian Cotfas, Daniela Ciobanu, Octavian Mihai Machidon. Characterization of Photovoltaic–Thermoelectric–Solar Collector Hybrid Systems in Natural Sunlight Conditions. Journal of Energy Engineering. 2017; 143 (6):04017055.
Chicago/Turabian StyleDaniel Tudor Cotfas; Petru Adrian Cotfas; Daniela Ciobanu; Octavian Mihai Machidon. 2017. "Characterization of Photovoltaic–Thermoelectric–Solar Collector Hybrid Systems in Natural Sunlight Conditions." Journal of Energy Engineering 143, no. 6: 04017055.
The performance of the hybrid structures PV/TEG/STC which consist of photovoltaic cells PV, thermoelectric elements TEG and solar collector STC is studied in this paper function of different levels of illumination from 30 suns to 130 suns (1 sun = 1000 W/m2). The concentrated light is obtained using a solar simulator with four parabolic xenon lamps and an optical mixer to ensure the quasi homogenous illumination of the hybrid system. The important parameters of the photovoltaic cells and of the thermoelectric generators are determined using the current-voltage characteristics. The measurements and control are realized using the NI-cRIO platform and the software is developed in LabVIEW.
Daniel T. Cotfas; Petru Adrian Cotfas; Laura Floroian; Dan I. Floroian. Study of combined photovoltaic cell/thermoelectric element/solar collector in medium concentrated light. 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP) 2017, 747 -752.
AMA StyleDaniel T. Cotfas, Petru Adrian Cotfas, Laura Floroian, Dan I. Floroian. Study of combined photovoltaic cell/thermoelectric element/solar collector in medium concentrated light. 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP). 2017; ():747-752.
Chicago/Turabian StyleDaniel T. Cotfas; Petru Adrian Cotfas; Laura Floroian; Dan I. Floroian. 2017. "Study of combined photovoltaic cell/thermoelectric element/solar collector in medium concentrated light." 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP) , no. : 747-752.
This paper presents the design of a system for studying photovoltaic cells PV, thermoelectric generators TEG, a solar collector SC and different hybrid structures comprising two or three of them in concentrated light. The concentrated light is obtained using a Fresnel lens and a sun tracker. The advantages of the system are: the reduction of the photovoltaic cells area, the use of the photovoltaic cells with high efficiency and the possibility to vary the levels of illumination up to 56 suns. The system control is achieved using the NI-cRIO and NI-myRIO embedded hardware and the software is developed in LabVIEW, using a mathematical algorithm for the sun tracker system.
Petru Adrian Cotfas; Daniel Tudor Cotfas; Carmen Gerigan; Octavian M. Machidon. System design to study hybrid systems in concentrated light using Fresnel lens. 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP) 2017, 753 -758.
AMA StylePetru Adrian Cotfas, Daniel Tudor Cotfas, Carmen Gerigan, Octavian M. Machidon. System design to study hybrid systems in concentrated light using Fresnel lens. 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP). 2017; ():753-758.
Chicago/Turabian StylePetru Adrian Cotfas; Daniel Tudor Cotfas; Carmen Gerigan; Octavian M. Machidon. 2017. "System design to study hybrid systems in concentrated light using Fresnel lens." 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP) , no. : 753-758.
It is well known that renewable energy, today more than ever, has undergone an exponential development. Thus, it is necessary to create an efficient, compact and relatively cheap system to be used in education and research, which allows studying these types of energy. The concept, design and implementation of such a system - RELab are presented in this paper. The RELab system is a very useful tool for students and engineers to learn about the two types of renewable energy: solar and wind energy. The system has two components: the NI ELVIS platform and the RELab add-on. The RELab add-on is a modular one and it can be easily redesigned for using the photovoltaic cell, the wind turbine and the solar thermal collector. The software used is built in the graphical programming language LabVIEW, and it is flexible and open.
Petru Adrian Cotfas; Daniel Tudor Cotfas. Design and implementation of RELab system to study the solar and wind energy. Measurement 2016, 93, 94 -101.
AMA StylePetru Adrian Cotfas, Daniel Tudor Cotfas. Design and implementation of RELab system to study the solar and wind energy. Measurement. 2016; 93 ():94-101.
Chicago/Turabian StylePetru Adrian Cotfas; Daniel Tudor Cotfas. 2016. "Design and implementation of RELab system to study the solar and wind energy." Measurement 93, no. : 94-101.
This work describes the technical details of a novel methodology which enables the parallel deployment and execution of hardware applications onto the same FPGA chip using dynamic partial reconfiguration. Our approach, which makes use of the PCAP (Processor Configuration Access Port) available on the latest generation of Xilinx Zynq Systems-on-Chip, allows the processing system to operate a fast partial reconfiguration of the programmable logic with little logic overhead. The advantages brought by this technique, like scalability, high performance and dynamic management of the programmable logic are being put to use in implementing laboratory works involving running the mathematical models of energy harvesting sources. This allows the same FPGA development board to be used by several student at the same time for running their applications. Thus, this is part of a larger research effort in which we aim to develop remote online hardware design laboratories with hardware multitasking support.
Octavian M. Machidon; Petru Adrian Cotfas; Daniel Tudor Cotfas. FPGA-enabled hardware multitasking applications in energy harvesting laboratories. 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME) 2016, 94 -97.
AMA StyleOctavian M. Machidon, Petru Adrian Cotfas, Daniel Tudor Cotfas. FPGA-enabled hardware multitasking applications in energy harvesting laboratories. 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME). 2016; ():94-97.
Chicago/Turabian StyleOctavian M. Machidon; Petru Adrian Cotfas; Daniel Tudor Cotfas. 2016. "FPGA-enabled hardware multitasking applications in energy harvesting laboratories." 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME) , no. : 94-97.
This paper describes a model and its PSPICE simulation for a hybrid electric generator that is composed of a photovoltaic cell and a thermoelectric generator. The focus is to combine both models to obtain a hybrid system model. The electrothermal models of the photovoltaic cell and thermoelectric generator are described. The simulations are done using the NI Multisim electronic circuit simulators. The comparison between the results obtained through simulation and through real measurements on commercial PV and thermoelectric generators is also presented.
Petru Adrian Cotfas; Daniel Tudor Cotfas; O.M. Machidon. Modelling and PSPICE simulation oi a photovoltaic/thermoelectric system. 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME) 2016, 179 -183.
AMA StylePetru Adrian Cotfas, Daniel Tudor Cotfas, O.M. Machidon. Modelling and PSPICE simulation oi a photovoltaic/thermoelectric system. 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME). 2016; ():179-183.
Chicago/Turabian StylePetru Adrian Cotfas; Daniel Tudor Cotfas; O.M. Machidon. 2016. "Modelling and PSPICE simulation oi a photovoltaic/thermoelectric system." 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME) , no. : 179-183.
This paper presents a new method developed to significantly reduce the necessary time for the ageing tests for different types of photovoltaic cells. Two ageing factors have been applied to the photovoltaic cells: the concentrated light and the temperature. The maximum power of the photovoltaic cells was monitored during the ageing process. The electrical dc and ac parameters of the photovoltaic cells were measured and analyzed at 1 sun irradiance, before and after the test stress. During the test, two photovoltaic cells are kept at maximum power point and the other two are kept at open circuit voltage point. The method is validated through the results obtained for the monocrystalline silicon solar cell.
Daniel Tudor Cotfas; Petru Adrian Cotfas; Dan Ion Floroian; Laura Floroian. Accelerated Life Test for Photovoltaic Cells Using Concentrated Light. International Journal of Photoenergy 2016, 2016, 1 -7.
AMA StyleDaniel Tudor Cotfas, Petru Adrian Cotfas, Dan Ion Floroian, Laura Floroian. Accelerated Life Test for Photovoltaic Cells Using Concentrated Light. International Journal of Photoenergy. 2016; 2016 ():1-7.
Chicago/Turabian StyleDaniel Tudor Cotfas; Petru Adrian Cotfas; Dan Ion Floroian; Laura Floroian. 2016. "Accelerated Life Test for Photovoltaic Cells Using Concentrated Light." International Journal of Photoenergy 2016, no. : 1-7.