SPV System Research Articles

Modelling and Simulation of Grid Connected SPV System with Active Power Filtering Features

In this paper, the detailed simulation studies for a grid connected solar photovoltaic system (SPV) have been presented. The power electronics devices like DC–DC boost converter and grid interfacing inverter are most important components of proposed system. Here, the DC–DC boost converter is controlled to extract maximum power out of SPV under different irradiation levels, while the grid interfacing inverter is utilized to evacuate the active power and feed it into grid at synchronized voltage and frequency. Moreover, the grid interfacing inverter is also controlled to sort out the issues related to power quality by compensating the reactive power and harmonics current component of nearby load at point of common coupling. Besides, detailed modeling of various component utilized in proposed system is also presented. Finally, extensive simulations have been performed under different irradiation levels with various kinds of load to validate the aforementioned claims. The overall system design and simulation have been performed by using Sim Power System toolbox available in the library of MATLAB.

A mathematical modeling framework to evaluate the performance of single diode and double diode based SPV systems

Abstract In order to predict the performance of a PV system, a reliable and accurate simulation design of PV systems before being installed is a necessity. The present study concerns the development of single and double diode model of solar PV system and ensures the best suited model under specific environmental condition for accurate performance prediction. The information provided in the manufacturers’ data sheet is not sufficient for developing a Simulink based single and double diode models of PV module. These parameters are crucial to predict accurate performance of a PV module. These parameters of the proposed solar PV models have been calculated using an efficient iterative technique. This paper compares the simulation results of both the models with manufacturer’s data sheet to investigate the accuracy and validity. A MATLAB/Simulink based comparative performance analysis of these models under inconsistent atmospheric conditions and the effect of variations in model parameters has been carried out. Despite the simplicity, these models are highly sensitive and respond to a slight variation in temperature and insolation. It is observed that double diode PV model is more accurate under low intensity insolation or shading condition. The performance evaluation of the models under present study will be helpful to understand the I-V curves, which will enable us in predicting the solar PV system power production under variable input conditions.

A Study of Boost Converter with Solar Photovoltaic System for Maximum Energy Efficiency

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, shading etc. The conversion of solar energy using SPV modules,change in insolation conditions which severely affect the efficiency and output power of the modules. Improvement in the efficiency of conversion of solar energy can be done by tracking the maximum power point of a PV module. Various types of MPPT charge controllers are available in the market. A dc-dc converter is an important component of a SPV system as it acts as an interface between the load and the SPV module. These dc-dc converters enhance the performance of the MPPT algorithms leading to an improvement in the overall efficiency of the SPV system. This paper presents the modeling and simulation of one diode equivalent circuit of solar photovoltaic module using MATLAB/SIMULINKTM along with the boost converter which gives an efficiency of 93.29%.

Optimization of Solar Photovoltaic Converters for Maximum Energy Efficiency

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, shading across it etc. The conversion of solar energy using SPV modules comes with its own problems that arise from the change in insulation conditions. These changes in insulation conditions severely affect the efficiency and output power of the SPV modules. For improving the efficiency of conversion of solar energy can be done by tracking the maximum power point of a PV module. There are so many types of MPPT charge controllers for doing this important work in SPV system. A dc-dc converter is essential in SPV system as it acts as an interface between the load and the SPV module. Three different basic types of converters are explained in this paper without any non-idealities. There are other types of dc-dc converters as well, but these converters from these three basic converters. Further by using these dc-dc converters the performance of the MPPT algorithms can be done for improving the overall efficiency of the SPV system.

Fuzzy logic based modeling and estimation of global solar energy using meteorological parameters

Global solar energy data is considered as the most important parameter in smart grid applications, particularly for sizing the photovoltaic system and demand driven supply. However the data of global solar energy is rarely available on hourly basis, even for those stations where measurement has already been done. Due to lack of such measured data, the estimation of global solar energy at the earth's surface is an important study in the present scenario to meet the energy requirement from green energy sources.This paper is based on fuzzy logic approach for modeling and estimating the global solar energy using mean duration sunshine per hour, temperature, latitude, longitude, altitude and months of the year as input parameters. Fortunately, these important for accurate parameters estimation of solar energy are commonly available. Results obtained from fuzzy logic approach are used for the prediction of SPV system output for smart grid application.

Interfacing of the SPV System with Off-grid Load by using Boost converter and Inverter

Interfacing of the SPV System with Off-grid Load by using Boost converter and Inverter

Performance Loss in Solar Photovoltaic Array due to Non-ideal Natural Conditions

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, and shading across it. Shading can occur when the PV arrays/modules get covered by shadows of passing clouds, buildings, etc., or even by shadows cast by other modules/arrays. As a result the ideal operation of the PV systems is severely affected the P-V and I-V characteristics. The modeling of nonlinear current-voltage characteristics of solar cells for performance prediction becomes difficult under the influence of shading. Non-uniform solar radiation due to shadows casted by the other panels/ modules, buildings, clouds, etc. can cause maximum power to change drastically. Partial shading of PV installations has an impact on its power production. For the simulated results it has been observed that 74.66% loss in I-V characteristics and 85.41% loss in P-V characteristics respectively. The power losses in the individual shaded cells would result in local heating and create thermal stress on the entire module/array resulting in hot-spot formation.

Integrated pest management in post-harvest maize: a case study from the Republic of Togo (West Africa)

A large-scale experiment on maize storage systems was carried out in Atakpamé (Plateaux region of Togo), between autumn 1996 and spring 1997. An integrated pest management (IPM) approach based on research findings at the International Institute of Tropical Agriculture (IITA) and intended to control insect pests in rural maize stores was compared with (1) the locally prevalent methods of storage of farmers from the Plateaux region and (2) with the storage system recommended by the National Plant Protection Service in Togo (SPV). Two storage systems were designed based on IPM principles, one using a local variety (chosen mainly for its excellent husk cover characteristics), the second including an improved variety (with higher yield and moderately good husk cover characteristics), and both depending on visual selection of cobs at harvest to reduce initial insect infestation. The experiment was conducted in a collaborative manner, including representatives of the SPV, farmers from the Plateaux region, and researchers from IITA. Population dynamics of major insects and associated losses to stored maize were monitored monthly over an 8-month period, while an on-site evaluation of pest infestation and losses was conducted after 6 and 8 months of storage. The performance of the different storage systems was evaluated in terms of pest densities, grain weight losses and cost-efficiency. The IPM-based systems were as effective as the pesticide-based SPV system in reducing infestation and grain losses. When only the incremental net returns from the storage practices were considered, both the IPM approach and the recommendations of the SPV performed better than the farmers’ methods of storage. However, when the yields (per hectare) of the different maize varieties used in the respective storage systems were included in the cost and return analysis, the IPM storage systems using the local variety performed worse.

Constitutively expressed phoP inhibits mouse-virulence of Salmonella typhimurium in an Spv-dependent manner.

In Salmonella typhimurium, the transcription of several virulence genes including spvB is regulated by the PhoP/PhoQ regulatory system. To further examine the relationship between the PhoP/PhoQ and Spv systems for virulence in mice, we examined a non-polar phoP mutation combined with different virulence plasmid genotypes for effects on virulence of S. typhimurium in the mouse model. PhoP-/Spv+ and PhoP-/Spv- mutants were not detectably recovered from the spleens of subcutaneously or orally inoculated mice. The phoP gene constitutively expressed from the lacZ promoter of a low copy number vector (phoP(C)) only partially complemented the non-polar phoP mutation for mouse-virulence in both the Spv+ and Spv- backgrounds; both PhoP(C) strains exhibited virulence equal only to a PhoP+/Spv- strain. Interestingly, in a PhoP+ background, the phoP(C) gene reduced splenic infection of the Spv+ but not Spv- salmonellae after subcutaneous or oral inoculation compared with the PhoP+ parents. Additionally, the phoP(C) gene in an Spv+ background reduced the net growth of salmonellae in macrophages in vitro; phoP(C) in an Spv- background was without effect. These data suggest that the constitutive expression of the phoP gene attenuates the virulence of S. typhimurium in mice in an Spv-dependent manner.

The spv virulence operon of Salmonella typhimurium LT2 is regulated negatively by the cyclic AMP (cAMP)-cAMP receptor protein system

The cyclic AMP (cAMP) receptor protein (CRP) was found to play a role in the growth phase regulation of the spv operon on the high-molecular-weight virulence plasmid of Salmonella typhimurium LT2. By using a lacZ reporter transcriptional fusion to the spvB structural gene on the single-copy virulence plasmid, it was found that while spvB transcription was induced in stationary-phase cultures, the induced level of expression was lower than that reported for the spv system in other serovars of Salmonella. Surprisingly, inactivation of the gene encoding the positive activator SpvR resulted in only a threefold reduction in spvB transcription. In contrast, spvB transcription in stationary-phase cultures was enhanced by 10-fold in mutants deficient in crp-encoded CRP or cya-encoded adenylate cyclase. Wild-type (i.e., 10-fold-lower) levels of spvB expression were restored by providing active copies of crp or cya on recombinant plasmids. Enhanced spvB transcription was not seen in crp or cya mutants in the absence of a functional spvR positive regulatory gene, showing that the cAMP-CRP system acted on spvB expression either in conjunction with or via SpvR. A lacZ transcriptional fusion to spvR could not be induced in stationary-phase cultures in the absence of functional SpvR, regardless of the cAMP-CRP status of the cells. When SpvR was provided in trans, transcription of the spvR-lacZ fusion was induced to similar levels in stationary-phase cultures with and without cAMP-CRP. These data are consistent with spvR being poorly transcribed from the single-copy virulence plasmid in S. typhimurium LT2 and with a suppression of this defect via inactivation of the cAMP-CRP system. The physiological significance of cAMP-CRP involvement in spv expression is discussed.

Efficiency of polymer sensitizer in photosensitized reaction of tris(bipyridine)ruthenium(II) complex‐containing polymer

AbstractPhotochemical properties of Ru(bpy)2(poly‐4‐methyl‐4′‐vinyl‐2,2′‐bipyridine)Cl2 (2) were studied and compared with that of Ru(bpy)3Cl2. Continuous irradiation of a solution, which contains polymer 2 as a photosensitizer, methylviologen (MV2+) or 4,4′‐bipyridinium‐1,1′‐bis(trimethylenesulfonate) (SPV) as an electron acceptor and triethanolamine (TEOA) as a sacrificial donor, resulted in the formation of viologen radical ion (MV+ or SPV−). The rate of formation of MV+ or SPV− for the polymer 2 system was smaller than that for the Ru(bpy)3 Cl2 systems. The reason for this fact was kinetically analyzed by quenching experiments of excited Ru(II) complexes by MV2+ or SPV, the photosensitized reactions of the TEOA–Ru(II) complex–MV2+ or ‐SPV systems, and the dye laser photolysis of the Ru(II) complex–MV2+ or ‐SPV systems.