Characteristics Of Photovoltaic Modules Research Articles

Assessment of spectral effects on outdoor characterization of PV modules using silicon reference cells with spectral filters

This article describes outdoor temperature-controlled measurement of various photovoltaic (PV) modules fabricated using different technologies and using reference cells with spectral filters. Short-circuit current measurements of all PV modules and reference cells were recorded simultaneously using 16-bits Keysight digitizers and high-resolution Agilent multimeters. The spectral incompatibility factor was calculated considering the spectral response of each device and the spectrum measured outdoors. Corresponding spectra were also generated by the simple model of atmospheric radiative transfer of the sun SMARTS2 and were additionally used to compare the spectral incompatibility factors. The validation of the measurement method was demonstrated by comparing the incompatibility factor calculated with variation of the short-circuit current relationship between the device under test and the reference cell over time. Additionally, it was evaluated how the relationship between spectral variation of irradiance and the spectral response of different technologies affects the productivity in thin-film modules. Main observation from measurements (performed in Labsol) was that a-Si/μ-Si, CdTe, and triple a-Si junction converted 0.21%, 2.47%, and 3.65% more irradiation into electric current (in summer), respectively, compared to c-Si technology. The PV CIGS module converted on average 0.26% more irradiation into electric current in winter compared to c-Si technology. The results help to understand the spectral effects on the working of outdoor PV module and the relationships between measured and modeled spectra, as well as errors introduced by the spectral incompatibility factor.

Obtaining electrical characteristics of a PV module by FPGA based experimental system

Electrical characteristics of photovoltaic (PV) modules are significant for using in PV array and standalone applications. Therefore, when designing a PV system, these characteristics must be considered. Some methods are developed to achieve the electrical characteristics of PV modules and one of them is using a capacitor where it is connected to output of the PV module as a load. This method based on measuring the current and voltage of the capacitor during its charging. Thus, the electrical characteristics of the module can be obtained by using these measurements. In this article, Field Programmable Gate Array (FPGA) based method with using a capacitor is proposed to get electrical characteristics of the PV module. The method firstly simulated in Matlab-Simulink environment and promising results are obtained. Then, the method is performed by the FPGA based experimental system. At the same time, to prove experimental results, the electrical characteristics are derived by using an electronic load device. The experimental results show that the electrical characteristics can be accurately obtained by the proposed method.

Parameter extraction of photovoltaic modules using a heuristic iterative algorithm

The single diode Rsh-model is considered to be an accurate and time-efficient modeling method for photovoltaic (PV) modules. However, the implicit equation in the model increases the complexity of solution. In this paper, after analyzing the parameters on the electrical characteristics of PV modules, a pure heuristic iterative method is proposed to extract the five parameters and to solve the implicit voltage and current equation simultaneously. Only three electrical key points specified in the manufacturer’s nameplate together with the Shockley equation are useful. Meanwhile, some pure heuristic strategies are used to minimize the error of the model curve. In order to evaluate the effectiveness of the method, parameters of three different PV modules are extracted, i.e., poly-crystalline, mono-crystalline, and thin-film silicon module. The results show competitive and superior performance to the De Soto model and analytic algorithms in terms of accuracy and computation speed, especially a-Si PV cell types. In addition, 99.45% of PV modules from California Energy Commission (CEC) database are identified successfully to verify the robustness. Further, the field data also indicate that the proposed algorithm can used to predict the real-time generation power of a PV power station at various operating conditions. Therefore, the proposed method can be an effective and efficient alternative for parameter extraction of all kinds of PV modules and arrays.

Theoretical and experimental analysis of photovoltaic module characteristics under different partial shading conditions

Recently, the renewable energy resources have gained more attention in the electricity sector as promising technology to tackle the depletion in the traditional energy resources. Solar energy grows rapidly due to its vast applications. The performance of Photovoltaic (PV) system is affected by partial shading that results from building, clouds, and fallen leaves. This paper investigates theoretically and experimentally the impacts of various cases of partial shading; such as vertical string, horizontal string, and single cell at environmental conditions on the current-voltage and power-voltage characteristics of 88 W PV panel. In addition, diagonal shading with multi steps is considered in the analysis. The experiments are conducted with considering various parameters; such as shading position and ratio to validate the simulated results. The results show that at 100% shading condition, the maximum power drops by 99.36 %, 43.7%, and 41.15% for horizontal, cellular and vertical shading at the same solar radiation level comparing with their initial state value. Horizontal string shaded has the highest negative impact on the power and efficiency among other types of shadings. The comparison between the theoretical and experimental results reveals considerable agreement between the theoretical and experimental results.

Photovoltaic Panel Temperature Monitoring and Prediction by Raman Distributed Temperature Sensor With Fuzzy Temperature Difference Threshold Method

Solar cells can operate at a lower efficiency after a certain temperature, which is caused by a negative thermal coefficient. Therefore, the temperature prediction of photovoltaic (PV) modules is critical to accurately evaluate the efficiency of photovoltaic devices. We propose and experimentally demonstrate a Fuzzy Temperature Difference Threshold Method (FTDTM) based on Raman Distributed Temperature Sensor (RDTS) system for the detection and prediction of PV module temperature. The FTDTM consists of four steps, i.e., division of the universe, establishment of fuzzy relationships, definition of relationship matrix and calculation of predicted temperature. The experimental results show that the proposed RDTS can detect and accurately predict temperature trends by using the FTDTM. When the system window base of the FTDTM is set to 2, the average absolute error of the predicted temperature is 1.08 °C, and the fluctuation range of prediction error is ±3.7 °C. In addition, the experiment studied some factors affecting temperature distribution characteristics of PV modules, including solar radiation intensity, surface dust and inclination angle. We provide a solution for large-scale PV module temperature detection and early warning through RDTS systems with FTDTM.

Determining the factors affecting the characteristics of photovoltaic modules in the conditions of Krasnoyarsk Krai

The paper determines the factors affecting the characteristics of photovoltaic modules in the conditions of Krasnoyarsk Krai. During the work the dependences of the energy of solar radiation in the territory of the Krasnoyarsk Krai on the height of the sun above the horizon, as well as the spectral composition of solar radiation on the same parameters were identified. The results obtained will help determine the rational modes of a photovoltaic power station and the need to use light filters in certain areas of the region.

Optimal Design of Photovoltaic Power Plant Using Hybrid Optimisation: A Case of South Algeria

Considering the recent drop (up to 86%) in photovoltaic (PV) module prices from 2010 to 2017, many countries have shown interest in investing in PV plants to meet their energy demand. In this study, a detailed design methodology is presented to achieve high benefits with low installation, maintenance and operation costs of PV plants. This procedure includes in detail the semi-hourly average time meteorological data from the location to maximise the accuracy and detailed characteristics of different PV modules and inverters. The minimum levelised cost of energy (LCOE) and maximum annual energy are the objective functions in this proposed procedure, whereas the design variables are the number of series and parallel PV modules, the number of PV module lines per row, tilt angle and orientation, inter-row space, PV module type, and inverter structure. The design problem was solved using a recent hybrid algorithm, namely, the grey wolf optimiser-sine cosine algorithm. The high performance for LCOE-based design optimisation in economic terms with lower installation, maintenance and operation costs than that resulting from the use of maximum annual energy objective function by 12%. Moreover, sensitivity analysis showed that the PV plant performance can be improved by decreasing the PV module annual reduction coefficient.

A method for hybrid extraction of single-diode model parameters of photovoltaics

This paper presents a hybrid method to extract the five unknown parameters of a single-diode photovoltaic (PV) model. The proposed method is a combination of analytical and optimization algorithms such that only two parameters, namely, series (Rs) and shunt resistance (Rsh), are estimated by using metaheuristic algorithms. The information of three major key points in datasheets provided by manufacturers is used for optimization and the sum of the squared error formulated. The rest of the unknown parameters, diode ideality factor (D), photo-generated current (Iph), and dark saturation current (Io) are obtained analytically. In order to predict the behavior of real performance characteristics of solar PV modules under different environmental conditions, a set of translational formulas have been used. Finally, performance indices, such as PV characteristics, absolute error in current, normalized root mean square error (nRMSE), maximum power, and relative maximum power error are estimated for six different types of PV modules from different technology to reveal the effectiveness of the proposed method. Through comparison with experimental data available in modules datasheet and existing method, it was found that the proposed method is sufficiently accurate.

Theoretical model of optical transmission and reflection characteristics of dusty PV modules

Modeling radiative transfer on a dusty photovoltaic (PV) module is a complicated problem. In this work, an improved optical light pathway model was established based on a three-layer system (dust particles–cover glass–solar cell); this system models radiative transfer by considering absorption, reflection, and transmission. Transmittance and reflectance formulae based on the light transmission and reflection pathway were obtained. Optical experiments were conducted for incident light with a spectral range of 0.30–0.7 μm to verify the improved model. The results show that when the thickness of the particle layer was larger than the sum of the minimum and maximum diameters, the theoretical spectral transmittance and reflectance agree well with the experimental data. The relative errors of spectrum transmittance and reflectance were 1.17–16.79% and 4.17–11.68%, respectively. Spectral transmittance through the composite layers was very low, and the dust particle composition and layer thickness had strong inhibiting effects on the transmission of incident light.

Parasitic resistance calculation of PV module at various irradiance based on three condition Lambert-W

Serial and parallel parasitic resistances of the photovoltaic (PV) module are needed to determine the characteristics and performance of the module. Its values are constant for a long period operation. Characterization of PV modules using direct irradiation of sunlight is rather difficult to obtain constant radiation under a clear sky condition and the measurement should be taken in a short time period less than 5 minutes. In this work, Rs and Rsh values were determined by characterizing PV module at various levels of sunlight intensity and modeled after Lambert-W function. A Solarland SLP100S-12 monocrystalline 100Wp photovoltaic module was illuminated at different intensity 100%, 75%, 50%, and 25 % using filters covered the PV module surface. Based on the measured I-U curves, three important parameters are generated for the Lambert-W calculation: short-circuit current (Isc), open-circuit voltage (Uoc), and also the current-voltage at the Maximum Power Point (Imp, Ump). The calculated values were 0.63Q + 0.027 for Rs and 93.2Q + 0.588 for Rsh and relative constant for filter variation which are not influenced by the intensity of the sun.

Autonomous Multifunctional Measuring Device for Monitoring the Characteristics of Photovoltaic Modules

The study provides a multifunctional measuring device that searches for the maximum energy output using a certain algorithm and calculates the fill factor and efficiency of a solar module. It also monitors the air temperature and relative humidity, the temperature of the solar module, the level of solar radiation, wind speed, and current and voltage of the solar module. An electrical circuit for measuring the current–voltage characteristic of photovoltaic modules is proposed. In addition, rechargeable batteries allowing measurements without connecting the device to a power supply ensure autonomy of the device. An algorithm is proposed for finding the point of maximum power of a photovoltaic module. The device is developed on the basis of an ATmega2560 microcontroller with additional sensors. The measuring device software sends all acquired data from the device to a computer to be saved in a database.

Design and Simulation of a Grid Tied Single Phase SPWM Inverter Using Matlab

The work objective is to design and simulate grid tie photovoltaic module with Simulink software, to investigate the characteristics of photovoltaic module as well describe the maximum. power point tracking using the single diode equivalent circuit. As well as developing single phase H bridge inverter a control circuit which generates output of a pure sine wave and voltage of alike frequency and magnitude such as the voltage of the grid. Sinusoidal pulse width modulation signal (SPWM) a common PWM method to achieve perturb and monitor (P&O), the maximum power point tracking (MPPT) method.

Performance prediction of PV modules based on artificial neural network and explicit analytical model

The accurate characterization and prediction of current-voltage characteristics of photovoltaic (PV) modules under different operating conditions is essential for solar power forecasting and ensuring grid stability. The traditional method based on the single-diode model is inconvenient and complex because the current-voltage equation is implicit. In this paper, a novel method combining an artificial neural network (ANN) with an explicit analytical model (EAM) is proposed for predicting the I-V characteristics of PV modules under different operating conditions. The EAM makes it efficient to obtain the I-V curves from the estimated model parameters due to its simplicity and explicit expression. The ANN based on the EAM is composed of a three-layer feedforward neural network, in which the inputs are solar irradiation and module temperature and the outputs are the four parameters in EAM. Once the ANN is built and trained by using the measured I-V curves, the shape parameters and I-V curve are predicted by only reading solar irradiation and temperature without solving any nonlinear implicit equations. The accuracy and capability of the proposed method are verified by the experimental data for different types of PV modules. Moreover, the dependence of shape parameters in the EAM on solar irradiation and temperature is investigated first.

PSO-Based Modeling and Analysis of Electrical Characteristics of Photovoltaic Module Under Nonuniform Snow Patterns

In this article, a novel universal multi-zone approach of photovoltaic (PV) modeling is proposed to determine the electrical characteristics of PV modules covered with nonuniform snow patterns under partial shading conditions. A precise estimation of the penetrating light into the snow layer on the surface of PV modules is obtained through the theory of Giddings and LaChapelle based on the physical and optical properties of the accreted snow. The single-diode-five-parameter equivalent circuit model of the PV unit is considered as the platform for the modeling approach. Original contributions are brought through: (1) the use of a contour-based discretization methodology that can separate any nonlinear PV characteristics to the multiple linear ones; (2) a swarm-based optimization methodology that is adapted to instantaneously update and evaluate the output characteristics of PV modules and (3) a power loss equation to represent the performance of non-uniformly-covered snowy PV panels. The proposed model was successfully tested using three different commercial types of PV technologies commonly used in North America. The accuracy of the proposed modeling approach for power loss determination was validated by processing real data of a 12-MW grid-connected PV farm. Due to the high extent of snow impact on the PV losses, the proposed model of PV modules could be regarded as a basis not only for analyzing PV plant performance, but also for optimizing the power converter design.

Performance evaluation of roof top solar photovoltaic systems in Tamilnadu

This manuscript reports the monitored performance results of roof top solar photovoltaic (PV) power plants in different parts of Tamilnadu, India. In this work, PV plants of capacities 84 kWp and 18 kWp located at Tirunelveli and Ranipet respectively in Tamilnadu are considered. During an eight month period, of September 2014 to April 2015, these plants had generated 43.99 MWh and 15.55 MWh units of electricity respectively. The average electricity production per day for the considered period of these plants is 181.74 kWh and 62.81 kWh respectively. The performance ratio (PR) of these plants PV1 and PV2 is found to be 0.52 and 0.86 respectively. The characteristics of poly crystalline PV modules and the performance of employed photovoltaic inverters are also analyzed.It is observed that external conditions like climate and bad weather significantly reduces the PV system output, whereas it reduces marginally due to inverter failure as observed from the values of energy yield and performance ratio of these plants. Online monitoring of PV plant with DC/AC line and phase voltages and current waveforms observed for the given day are also presented.

A Fast GMPPT Algorithm Based on PV Characteristic for Partial Shading Conditions

Photovoltaic (PV) modules experience some partial shading conditions (PSC) due to some various factors. In that kind of a condition, a few maximum power points (MPPs) possibly appear on the power-voltage (P-V) curve, which increases the tracking difficulties. It is known that maximum power point tracking (MPPT) may not be realized by hill climbing (HC) based conventional MPPT algorithms under PSCs. In this context, this paper presents a novel micro converter based algorithm that was developed by using P-V characteristics of PV modules. Unlike voltage or duty ratio scanning techniques, this paper introduces a new deciding method to determine the correct global MPP (GMPP) region. For this, the proposed method uses some duty ratios that were calculated corresponding to each MPP region. Thus, the initialization of duty ratio is done properly, which results in high tracking speed and accurate tracking of the GMPP. The other advantages of the proposed algorithm are structural simplicity, less computational burden, and ease of implementation with a basic microcontroller. The simulation results show that this algorithm has fast tracking capability and it manages to track GMPP for PSCs correctly, since it includes an artificial scanning procedure. Single ended primary inductance converter (SEPIC) is built in order to validate the proposed global maximum power point tracking (GMPPT) algorithm. The performance of the proposed GMPPT technique is verified by experimental studies. The results show that the proposed GMPPT technique is fast by up to five times than an adaptive full scanning strategy and improved IC algorithm. Furthermore, the proposed algorithm can be commercially used in micro converters, since it is compatible with small number of bypass diodes in a module.

Online extraction of physical parameters of photovoltaic modules in a building-integrated photovoltaic system

Building-integrated photovoltaic systems are solar photovoltaic modules that are used to replace traditional building construction materials to generate electrical energy. Photovoltaic modules are generally installed on the roofs or facades of buildings and cannot be monitored by conventional methods. This work presents a new online technique for analysing the current-voltage characteristics of photovoltaic modules installed on the facades of building-integrated photovoltaic systems. The proposed method, which is based on the modified double-diode model, can extract six physical parameters of the photovoltaic module that rely on the current and voltage at the short-circuit and open-circuit points and at the maximum power point. Unlike the approaches from existing studies, the method proposed in this paper requires only the current at the maximum power point. By measuring the solar irradiance, wind speed and average temperature of the photovoltaic module, the current and voltage at the short-circuit and open-circuit points can be calculated. To study the accuracy of the proposed models, the absolute error and root mean square error of individual photovoltaic modules are examined. The results indicate that the minimum absolute error of the current appears near the maximum power point. Moreover, the proposed simulation of the current-voltage characteristic curves achieves a lower root mean square error value and exhibits a better ability to represent the current-voltage characteristics of the photovoltaic modules. In addition, methods are used to extract the six parameters of the photovoltaic module, which operates in the building-integrated photovoltaic system. The experimental results show that the prediction of the current-voltage characteristic curves achieves the lowest root mean square error values at the short-circuit and open-circuit points and at the maximum power point. Furthermore, regardless of whether operating in the building-integrated photovoltaic system, the six parameters of the photovoltaic modules with the same initial characteristics extracted via the proposed methods have similar numerical ranges under standard test conditions. Based on these conclusions, the six parameters based on the modified double-diode model are useful and practical for the simulation and evaluation of the current-voltage characteristics of the photovoltaic module in the building-integrated photovoltaic system.

Assessment of power generation performance characteristics using different solar photovoltaic technologies

Solar energy is a relatively free renewable, clean, green, and environmentally friendly energy resource produced from the sun, using different technologies like solar thermal and photovoltaic (PV) modules to generate heat and electricity, respectively. This paper aims to assess and compare the power generation performance characteristics of different solar PV module technologies by simulation, deploying identical input temperature and irradiance parameters. The solar PV designs were simulated using PVsyst Version 6.73 for 26.0 kW annual power and 42.9 MWh/year annual yields using the climate data of Sydney, Australia. The results show that monocrystalline solar technologies needed an area of 163m2, while polycrystalline and thin films needed areas of 173m2 and 260m2 respectively to generate 42.9MWh annual yield. The monocrystalline PV modules are more efficient at solar energy conversion than polycrystalline and thin film technologies, respectively (94.2% and 62.7%). The symmetric semi-toroid dome of sun heights against azimuthal angles show 13 bimodal pyriforms, that cut the azimuths at least twice on each of the optimisation lines. These optimal solution points were visible for every sunlight hour of between 6 and 18 hours (inclusive). They show convex sets of global optima (or local optima) with one minimum in the interval of convexity. Also, each of the minimum points for each of the 13 directed fish-like bimodal pyriforms was on ±60° azimuth. However, the assessment of respective PV module characteristics with respect to variation of irradiation and temperature, show that the general results from simulation displayed disparate changes in the voltages and currents of the generated power with respect to different solar PV modules. The proposed semi-toroid model indicates that many optimisation solutions for easier, cheaper, quicker and more efficient power generation are possible with appropriate design. It is recommended that the installation of a single-axis solar tracker or maximum power point tracker could overcome the azimuth angle effect.

High-throughput, outdoor characterization of photovoltaic modules by moving electroluminescence measurements

Fast and nondestructive quality control tools are important to assess the reliability of photovoltaic plants. On-site inspection is essential to minimize the risk of further damage and electrical yield losses. The most effective way of achieving this is with highly sensitive imaging techniques such as luminescence or infrared thermography imaging. Nowadays, electroluminescence (EL) is used at nighttime to detect defects such as local cell changes, series resistances, and shunts. However, the drawback of this method is low measurement throughput. To increase the throughput, indium gallium arsenide detectors with a resolution of 640 × 512 pixels are used, for which short integration times are possible to acquire EL images. For such short integration times, even moving image acquisition and movie recording are feasible to detect the mentioned defects. An outdoor EL setup is presented for mobile handheld recording, which can even be used under low-light conditions, below 100 W / m2, at daytime. Experiments show that 5 ms integration time is a good compromise between low contrasts for lower integration times and motion blur for higher integration times. The camera prototype has an onboard computer to avoid image transmission losses and an external lithium polymer battery power supply for improved mobility.

Studies of the PV Array Characteristics with Changing Array Surface Irradiance

This paper presents a brief analysis of the photovoltaic (PV) modules that are currently commercially available. The most used calculation formulas and measurement procedures used for evaluating the power characteristics of photovoltaic PV modules are given. The possible causes of power losses of solar cells and modules are described, including losses caused by design features. The theoretical calculations and experimental results of measuring the characteristics of silicon PV arrays with changing surface irradiance are compared. The calculated and experimental dependences of the power output variation of the ISM-50 photovoltaic module with changing its tilt angle are presented. It is shown that there is a significant discrepancy between theoretical studies and experimental results. A hypothesis has been put forward about the dependence of a real decrease in power characteristics and refraction indices of PV array protective coatings. An adjustment factor is proposed taking into account the decrease in the solar radiation output on the silicon photocell surface when passing through the antireflective protective coatings of the PV module. The conclusions drawn from the results of this work indicate that the identified factors affecting the electricity generation by photovoltaic converters need to be considered.