Characterization Of PV Modules Research Articles

Experimental characterization of photovoltaic systems using sensors based on MicroLab card: Design, implementation, and modeling

In the most case, the manufacturer measure electrical or thermal parameters under environment conditions that are artificial in the laboratory scale and rarely occur in reality outside. Therefore, the characterization of photovoltaic modules under dynamic environmental conditions will be an essential phase to go forward with renewable energy technology. In this study an experimental setup, uses sensors (current, voltage and temperature) interfaced with a MicroLab data acquisition card, was developed with low-cost to measure current-voltage and power-voltage curves of the PV modules under dynamic environmental conditions. In addition to on-site measurement of meteorological parameters like solar irradiance, temperature, humidity and wind speed, spatial modeling of the conditions was performed using the WRF weather model. A performance-based experimental method for PV module characterization under dynamic conditions was presented along with suitable modeling tools. The obtained results indicate that the evolutionary algorithms proved effective for parameter extraction of the three common electrical models single diode, double diode and triple diode, from experimental module test data and MLBSA algorithm successfully modeled the experimental I–V curves, showing good agreement with measured current, voltage and power values based on statistical metrics.

Design and characterization of a continuous solar simulator for photovoltaic modules with automatic I-V curve acquisition system

This paper presents the development, characterization, and testing of a continuous large-area solar simulator for PV modules with an automatic I-V curve acquisition system and the results of a CIGS PV module over 25 h of light soaking. The simulator was developed to perform the IEC 61215 stabilization test and automatic characterization of PV modules during indoor testing. The equipment records the I-V curves of the PV module at programmed time intervals so that the change in the electrical characteristics of the PV modules can be tracked over time. The test plane has an area of 1.2 × 2 m and an irradiance of 800 W/m2. The simulator was installed in a container and consists of 16 metal halide lamps of 1 kW each. The simulator is characterized by temporal instability, spatial non-uniformity, and spectral mismatch, resulting in CCB classification. The I-V curves of the tested PV module were measured every 30 s, with 200 I-V points per curve. The power change of the tested module occurs mainly in the first 12 min and stabilizes after about 5 h under the conditions selected for the test. The developed device can save significant resources compared to commercial continuous solar simulators. The ability to automatically track changes in PV module electrical parameters during light-soaking tests is presented in detail and provides important information for future work related to the development and characterization of solar simulators of this type.

Accelerated UV stress testing and characterization of PV-modules: Reliability analysis using different encapsulants and glass sheets

Ethylene vinyl acetate (EVA) is the most commonly used encapsulant material in photovoltaic (PV) module fabrication. However, during long-term operation in the field under hot and dry climates, it turns yellow and finally brown due to action of ultraviolet (UV) light. Therefore, UV-light is a major concern causing photodegradation of encapsulant and significant loss in maximum power (Pmax) of PV-module. The main objective of this study is to provide deeper insights into degradation of electrical parameters in PV-modules under influence of UV-light and temperature, and minimize the impact of UV induced degradation (UVID) by replacing the encapsulant EVA with poly vinyl butyral (PVB). Four polycrystalline PV-modules, fabricated in different combinations from two types of encapsulants, namely PVB and EVA, and glass sheets, namely soda-lime and quartz, are subjected to an accelerated UV stress test for 350 h. Visual inspection, electroluminescence, infrared imaging, insulation resistance, wet leakage current, and maximum power determination tests were performed to characterize PV-modules intermittently throughout accelerated UV stress test. Based on obtained electrical parameters, PVB/soda-lime experienced the lowest 3% loss in Pmax, whereas EVA/quartz experienced the highest 7% loss in Pmax. In other two samples, EVA/soda-lime and PVB/quartz, Pmax reduced by 4% and 5% respectively.

Implementation of a plug and play I-V curve tracer dedicated to characterization and diagnosis of PV modules under real operating conditions

The performance assessment of operating photovoltaic modules under real conditions is a necessity. Engineers usually use commercial I-V curve tracers available in the market. Nevertheless, most of them are expensive and limited in the input voltage. This paper outlines a low-cost equipment for tracing current-voltage characteristics of photovoltaic systems using a relay to connect the operating module under test to the varying load, which is a power MOSFET transistor. The new developments of this work include the design of an RC circuit to generate a steady gate-source voltage amplitude controlled via a PWM varying duty cycle. Also, a flexible modular voltage measurement that consists of a voltage booster to increase the input voltage capacity of the developed curve tracer is proposed. This paper investigated the impact of PV module degradations such as discoloration, cell cracks, and PID on the I-V curve in the case of crystalline technology and compared to similar modules taken as reference.

Modeling temperature and thermal transmittance of building integrated photovoltaic modules

This study aims at contributing to the progress of the modeling of the thermal behavior of Building Integrated Photovoltaic (BIPV) modules, a progress that runs way behind the pace of development in other areas of characterization of PV modules, such as the electrical one. To this end, a model based on the physics of heat transfer and optics is proposed, allowing the calculation of the temperature of BIPV modules and their thermal transmittance (U-value) in real operating conditions. The main contribution of this model is to include the impact of some parameters not considered so far, like the solar irradiance and the electrical efficiency. After being validated with experimental data, the model has been used to simulate single and double PV glazing, that compared later with common glazing with the same composition and configuration demonstrate the non-equivalent performance between them, showing differences of about 35% in the U-value under high irradiance conditions. This way, a clear disagreement with the current standard testing procedures occurs, something that should be reviewed. The tool proposed allows the complete study of the thermal behavior of BIPV modules and can help in the development of new specific standard procedures for a more realistic characterization of BIPV modules.

Experimental platform for outdoor characterization of photovoltaic modules under hot climate

This paper presents a novel test facility for outdoor characterization of photovoltaic modules. The test facility named “I-V bench” has been recently installed, within a sudano sahelian climate, in Ouagadougou (Burkina Faso). Our principal aim with this bench is to carry out different studies on photovoltaic energy productivity through the characterization of PV modules in real operating conditions. The experimental platform can receive up to 24 modules, from 1 Wp to 600 Wp that can be simultaneously monitored. In this paper, the principle of the operation of the test-bench is described. Then, current and voltage (I-V) data collected with the bench are used to find out the STC values of three different performance settings (open circuit voltage, short circuit current and maximum power) of PV modules. Several methods are proposed in the literature to translate outdoor values into standard conditions ones. Here, a comparison of results obtained with three methods, includitang the standard NF EN 60891: 1995-02, is performed. It has been shown that although the I-V data translation with model L5P leads to good accuracy, the best results for all photovoltaic parameters are obtained with the standard NF EN 60891: 1995-02.

Uncertainties on the outdoor characterization of PV modules and the calibration of reference modules

This paper presents the IES-UPM experience in the outdoor characterization of PV modules. On days with clear sky conditions, a rather simple device consisting of a thermally-insulated wooden box allows the STC characteristics and the thermal coefficients of PV modules to be measured with low expanded uncertainty (±1.87% in power (k = 2)). Particular attention has been paid to the calibration of the reference cell used for measuring the irradiance and making our measurements traceable to the International System of Units (S.I.). Furthermore, the uncertainty on the irradiance and module temperature measured by the reference PV modules calibrated with the help of this box has also been analyzed in relation to the angle of incidence of the direct irradiance. We think this experience is particularly interesting for local measurements in many countries currently incorporating PV plants in their electric grid, but lacking in specialized PV laboratories equipped with expensive solar simulators.

Electrical Characterization of PV Modules employing Supercapacitors – A Scalable Method for Field Metrology

Electrical Characterization of PV Modules employing Supercapacitors – A Scalable Method for Field Metrology

Comprehensive study of performance degradation of field‐mounted photovoltaic modules in India

AbstractThe All India Survey of Photovoltaic Module Reliability 2014 is an enhanced version of the survey conducted in the previous year, with detailed characterization of PV modules including current‐voltage, infrared and electroluminescence imaging, visual inspection, insulation resistance test and interconnect breakage test. More than a thousand modules were inspected in the field and the main results of the survey are presented in this paper. The average Pmax degradation rate for the so‐called ‘good’ modules (Group X) is 1.33%/year which is higher than that commonly projected by manufacturers, and widely employed in financial calculations. Modules falling in the ‘not‐so‐good’ category (Group Y) show even higher degradation rates, and it is at least partly due to higher number of micro‐cracks in the modules, and increased degradation of the packaging materials like encapsulant, backsheet, etc. Modules in ‘Hot’ climates degrade faster than modules in the ‘Non‐Hot’ climates. Degradation in fill factor is the primary cause for performance degradation in the young modules (ages <5 years), whereas short‐circuit current degradation is the main contributor to power degradation in the older modules. Small installations (<100 kWp capacity) show higher degradation than large systems, which may be partly due to lack of proper due diligence by the owner at the time of procurement and installation.

A sensitivity analysis of the stepwise measurement procedure for the characterization of large area PV modules

A major issue in the characterization of photovoltaic modules is the limitation of the homogenously irradiated area provided by the available sun simulators. Therefore the StepwiseMeasurementProcedure for the Characterization of Large-area PV Modules (SMP) was developed recently. This concept enables the characterization of modules with aperture areas larger than the area provided by a given sun simulator. In previous investigations the procedure demonstrated good applicability and high accuracy. In a real application environment, however, conditions like temperature and stray light might influence the measurement. Also, particular variations within a module like e.g. defective cells may lead to higher uncertainties for the results of the SMP. Therefore, an investigation of the impact of these factors on the accuracy of the procedure is performed. The results show that the impact of most factors can be minimized and even eliminated. Therefore, recommendations for the practical application are given.

Sun trajectory modeling for specific location using PV measured data

In order to research the PV module characterization it was necessary to develop the Prototype PV characterization station. Among other possibilities derived from the measured results of Prototype PV characterization station it is also possible to model the Sun trajectory at installation location. Such measured results can be used to model Sun trajectory. Also, the Sun trajectory generated using presented model is verified with conventional analytical model Sun trajectory. Some conclusions for new approach are presented and discussed.

Validation of Methods for PV Module Characterization

In this paper the standard method for PV module parameters calculation is validated while compared to real measured U-I characteristic of PV module. The standard method uses nominal data of PV module which are gained in laboratory conditions and often can produce very different values from those gained on real location. The PV module is described by parameters gained from real measured U-I characteristic which contains irradiation and temperature influence, as well as all other less significant influences which are often neglected in laboratory conditions. The comparison of modeled and measured results provides quality assessment of gained PV module parameters from nominal data. Result parameters with small errors will mean that model methods are good, while those with great error will be discarded as poor model methods and will be provided with better replacement. Finally, gained model will be good description of PV module for specific location.

Luminous and solar characterization of PV modules for building integration

The optical characterization of different PV modules for integration in buildings (BIPV) is presented in this paper. The investigated PV modules are laminated glasses (PV laminates) suitable for integration in façades and windows. They are made of different PV cell technologies and some of them present a certain transparency degree, making possible to combine daylighting properties with solar control and electrical generation. The approach is based on spectral UV/vis/NIR reflectance and transmittance measurements of the different considered samples, both at normal incidence and as a function of the angle of incidence when it is possible. The European standard protocols are used to determine the luminous and the solar characteristics of each sample, enabling the optical assessment of these PV modules as building elements. The results indicate the good properties of PV laminates in terms of daylighting and solar control capabilities allowing a feasible efficient integration in building façades and windows. The obtained characteristic parameters can be used to simulate the influence in the energy balance of a building of different types of PV modules integrated in façade or window elements.

Advanced PV Plant Planning based on Measured Energy Production Results - Approach and Measured Data Processing

The objective of this research was to develop a model for a prototype measurement station built for recording data relevant for the production of electrical energy by PV modules in order to improve the modelling. The measured data for specific time period (annually), or periods (monthly or otherwise), was processed after measurement results are available, and allow better and more accurate planning of the PV plant. Therefore, data processing time is not significant since it is not used in real-time. Measurement station was designed in a way which allows for the total energy production to be quantified for various modes of operation (fixed, single-axis or dual-axis tracking). In this article energy production in weekly time periods is analyzed since data for short time periods is available and the main goal is to find the most accurate method in PV module characterization. Once the data are obtained, it will be possible to propose improvements of conventional analytical models when measured and modelled results are compared. These improvements will be specific for the location on which prototype measurement station is installed. The proposed improvements will allow upgrades in model estimations without the need for additional measurements by a prototype measurement station.

NOVEL TECHNIQUE IN CHARACTARIZING A PV MODULE USING PULSE WIDTH MODULATOR

The fabrication and characterization of PV modules are always done under standard test conditions (STC ). However, The condition of operation are often far from thisstandard condition s. As a result, developing a characterization circ uit is considered as a point of interest for researchers.This paper presents a new methodology in characterizing a PV module using an electronic load circuit. The circuit is implemented using a power MOSFET driven by a pulse width modulator (PWM) developed by LABVI EW. The system is tested and its results are validated by comparing i t with simulation results performed by Comsol Multi physics and Matlab. The system shows high accuracy with respect to the previous pu blished work with lower cost and higher simplicity.

Characterization of thin film PV modules under standard test conditions: Results of indoor and outdoor measurements and the effects of sunlight exposure

Photovoltaic modules based on thin film technology are gaining importance in the photovoltaic market, and module installers and plant owners have increasingly begun to request methods of performing module quality control. These modules pose additional problems for measuring power under standard test conditions (STC), beyond problems caused by the temperature of the module and the ambient variables. The main difficulty is that the modules’ power rates may vary depending both on the amount of time they have been exposed to the sun during recent hours and on their history of sunlight exposure. In order to assess the current state of the module, it is necessary to know its sunlight exposure history. Thus, an easily accomplishable testing method that ensures the repeatability of the measurements of the power generated is needed.This paper examines different tests performed on commercial thin film PV modules of CIS, a-Si and CdTe technologies in order to find the best way to obtain measurements. A method for obtaining indoor measurements of these technologies that takes into account periods of sunlight exposure is proposed. Special attention is paid to CdTe as a fast growing technology in the market.

Solar hydrogen production: A spanish experience

Abstract In the framework of the solar energy activities carried out by INTA's Energy Laboratory, in 1990 a programme on solar hydrogen production and utilization was started. Within the general agreement between INTA and the regional government of Andalucia, a test and research plant for solar hydrogen production via water electrolysis was designed and erected in Huelva. The construction of the plant started in November 1991 and was finished in February 1992. The main objective of this facility is to test and evaluate the different technologies associated with solar hydrogen production, as well to stimulate research and development in this field in Spain. The plant is composed mainly of a 8.5 kW photovoltaic field with a flexible configuration of output voltage and current, and a 5.2 kW alkaline electrolyser. A test bench for PV module characterization, a conventional a.c./d.c. converter for electrolyser characterization and a d.c./d.c. maximum power point tracker as power matching system complete the test facility. The paper contains a technical description of the installation, the test plan to be performed, results concerning electrolyser characterization and some preliminary results of continuous operation.