Characteristic Curve Of Photovoltaic Module Research Articles

Plotting Characteristic Curves of Photovoltaic Modules: A Simple and Portable Approach

This work presents a simple and low-cost curve tracer for the analysis of photovoltaic (PV) modules. The proposed system allows the plotting of current versus voltage (I-V) and power versus voltage (P-V) characteristics in a fast and straightforward approach employing a dc-dc single-ended primary inductance converter (SEPIC) topology. Thus, it is possible to obtain variable impedance seen from the PV source by properly adjusting the duty cycle imposed to the active switch and consequently, by plotting several points that accurately define the aforementioned curves. The curve tracer is analyzed through simulation and experimental tests while its performance is evaluated considering uncontrolled environmental conditions and also the eventual occurrence of partial shading.

A new approach for modeling photovoltaic modules based on difference equation

A modeling method of photovoltaic (PV) module based on difference equation is proposed. Firstly, the derivative of the I–V characteristic curve is solved based on the extracted parameters. Then, the I–V characteristic curve of PV module is obtained using the difference equation combined with the photocurrent by recursive algorithm. This modeling method effectively avoids the need of iterative algorithm. In addition, when the temperature of PV module is constant, another method is proposed to obtain the I–V characteristic curve under any solar irradiance by using the I–V characteristic curves when the solar irradiance is 200 and 1000 W/m2 respectively. In this case, only a single model parameter is required. The parameters of the model are extracted by a numerical method. Firstly, the region where each parameter affects the I–V characteristic curve is analyzed. And each parameter is given an initial value according to the analytic expression. Then, according to the criterion of the coefficient of determination, the values of each parameter are dynamically adjusted to achieve the optimal value. This method avoids such disadvantages as long running time and difficult convergence. Finally, the effectiveness of the two new models and the corresponding parameter extraction method are verified by simulation.

Development of a photovoltaic characteristics generator based on mathematical models for four PV panel technologies

A good study of photovoltaic system requests to have very precise 
 current-voltage characteristic curves of photovoltaic modules for different technologies. The photovoltaic emulator provides an efficient solution to maintain the same current-voltage output of photovoltaic module. It includes three parts: the PV model, the control strategy, and the power converter. This paper provides three classes of modeling and simulation of photovoltaic arrays and presents the synthesis results of the current-voltage characteristic performances obtained by the modeling approaches. The models of the first class are based on electrical circuit model, those of the second class are based on multiple straight lines model, and for the third class, it is based on the look up table. The mathematical model is built using MATLAB/ Simulink, and an experimental bench was carried out to acquire an up-to-date and representative experimental database of four PV panels. This database is used for the validation of these models for the different PV panel technologies under Moroccan meteorological conditions. Following this comparative study, we came to a high agreement between the experimental and simulated current-voltage characteristics for the emulator under study.

Development of an outdoor photovoltaic module test platform

A new outdoor photovoltaic (PV) module test platform was introduced to measure I–V characteristic curve of PV module in this study. The proposed test platform was designed centring on the programmable electronic load (E-load) which used the transfer characteristics of metal–oxide–semiconductor field-effect transistor (MOSFET) and controlled PV module output current by controlling the drain current I D of MOSFET indirectly. Ultimately, controlling the PV module work on any operating point of the I–V curve. This test platform can automatically shift operation mode contraposing the I–V curve of PV module. It can continuously measure I–V curves and ambient data in the outdoors including the total irradiance, temperature of PV module back sheet and ambient temperature. The test results show the proposed test platform's accuracy meets the user's requirements, and more details of I–V curve can be obtained than by using traditional measurement mode.

Optimal Extraction of Photovoltaic Model Parameters Using Gravitational Search Algorithm Approach

Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate extraction of PV model parameters is proposed in this paper. GSA is a population based heuristic optimization method which depends on the law of gravity and mass interactions. In this optimization method, the searcher agents are collection of masses which interact with each other using laws of gravity and motion of Newton. The developed PV model utilizes mathematical equations and is described through an equivalent circuit model comprising of a current source, a diode, a series resistor and a shunt resistor including the effect of changes in solar irradiation and ambient temperature. The optimal values of photo-current, diode ideality factor, series resistance and shunt resistance of the developed PV model are obtained by using GSA. The simulations of the characteristic curves of PV modules (SM55, ST36 and ST40) are carried out using MATLAB/Simulink environment. Results obtained using GSA are compared with Differential Evolution (DE), which shows that GSA based parameters are better optimal when compared to DE.

Maximum Power Point Tracking Method Based on Modified Particle Swarm Optimization for Photovoltaic Systems

This study investigated the output characteristics of photovoltaic module arrays with partial module shading. Accordingly, we presented a maximum power point tracking (MPPT) method that can effectively track the global optimum of multipeak curves. This method was based on particle swarm optimization (PSO). The concept of linear decreases in weighting was added to improve the tracking performance of the maximum power point tracker. Simulation results were used to verify that this method could successfully track maximum power points in the output characteristic curves of photovoltaic modules with multipeak values. The results also established that the performance of the modified PSO-based MPPT method was superior to that of conventional PSO methods.

Methodology and experimental system for measuring and displaying I–V characteristic curves of PV facilities

AbstractThis paper describes a methodology and the developed system for measuring, capturing, and displaying I–V and P–V characteristic curves of photovoltaic (PV) modules or arrays based on single‐ended primary inductance converters (SEPIC) in parallel connection, operating in interleaved mode. The proposed methodology and the developed system allow the real time capture and displaying of the I–V and P–V curves of a PV panel or array, and show several advantages with regard to classical methods: simple structure, scalability, fast response, versatility, direct display, and low cost. The measuring of the characteristic curves of PV modules includes high speed of response and high fidelity, with low ripple. An experimental prototype based on four SEPIC converters in parallel connection has been implemented to validate the proposed methodology. This new methodology and experimental system has been registered in the Spanish Patent and Trademark Office with the number P200930198. Copyright © 2009 John Wiley & Sons, Ltd.

Electronic Controlled Device for the Analysis and Design of Photovoltaic Systems

The characterization and design of photovoltaic systems is a difficult issue due to the variable operation atmospheric conditions. With this aim, simulators and measurement equipments have been proposed. However, most of them do not deal with real atmospheric conditions. This letter proposes an electronic device that first measures the real evolution of the I-V characteristic curves of photovoltaic modules and generators, and then physically emulates in real time these curves to test photovoltaic inverters. The device consists of a dc-dc converter, a microcontroller and a data storage unit. The two operation modes (emulation and measurement) are digitally driven by the microcontroller. The converter current is controlled by means of a variable-hysteresis control loop, whose reference is provided by the microcontroller. In addition, a digital voltage control loop is designed to find out the complete characteristic curves of the photovoltaic generators. A 15-kW prototype is designed and built that can measure three times per second the characteristic curves of up to seven generators and then emulate their electrical behavior to test photovoltaic inverters. With the proposed device, the optimal configuration and performance of photovoltaic modules and generators, as well as the operation of photovoltaic inverters can be thoroughly analyzed under real atmospheric conditions.

Methodology for Photovoltaic Modules Characterization and Shading Effects Analysis

This work describes the methodology, basic procedures and instrumental employed by the Solar Energy Laboratory at Universidade Federal do Rio Grande do Sul for the determination of current-voltage characteristic curves of photovoltaic modules. According to this methodology, I-V characteristic curves were acquired for several modules under diverse conditions. The main electrical parameters were determined and the temperature and irradiance influence on photovoltaic modules performance was quantified. It was observed that most of the tested modules presented output power values considerably lower than those specified by the manufacturers. The described hardware allows the testing of modules with open-circuit voltage up to 50 V and short-circuit current up to 8 A.