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Das A.K.,Center for Study of Science
Solar Energy | Year: 2011

The J-V equation of a solar cell is implicit and requires iterative calculation to determine the fill factor and the maximum power point. Here an explicit model for J-V characteristic is proposed which is applicable to a large variety of solar cell. This model allows an easy estimation of fill factor from four simple measurements of the bias points corresponding to V oc, J sc, and any two voltage values lying between 0 and V oc, where V oc is the open circuit voltage and J sc is the short circuit current density. © 2011 Elsevier Ltd.


Das A.K.,Center for Study of Science
Solar Energy | Year: 2012

Recently a simple explicit model was introduced to represent the J-V characteristics of an illuminated solar cell with parasitic resistances and bias dependent photocurrent as v m+j n=1. Here the normalized voltage, v and normalized current density j can be represented as v=V/V oc and j=J/J sc respectively, where V oc is the open circuit voltage and J sc is the short circuit current density. This model is useful for design, characterization and simple fill factor calculation and its applicability was demonstrated with the measured data of a wide variety of solar cells. This explicit form is intuitive and hence the model lacks the analytical support. In this paper an analytical derivation of this closed form explicit model is presented, which is derived from the physics based implicit J-V equation. The derivation expands the scope of model applicability and provides a new insight of analytical modeling of the solar cell. © 2011 Elsevier Ltd.


Lavania C.,Soliton Technologies | Rao S.,International Institute of Information Technology Bangalore | Subrahmanian E.,Center for Study of Science
IEEE Systems Journal | Year: 2012

Solar irradiation tends to vary greatly throughout the day. The difference is very large especially between the early hours of sunshine, and during the peak hours of the day. Yet, it is desirable to supply a nearly constant amount of power to loads or power grids for high reliability. Hence, we propose a technique aimed at reducing the variation in solar power generation. Solar irradiation data is considered as a time-series data and the approach involves conversion of this data to the frequency domain through Fourier analysis. A more balanced supply by a set of plants is devised by interconnecting the plants, which also requires finding the optimum number of plants to connect using the above analysis. The effectiveness of the procedure is demonstrated by applying a suitable supply prediction algorithm over the individual plants and the effective data for the plants, using real data from Nevada, Texas, and California. © 2011 IEEE.


Recently a simple explicit model was introduced to represent the J - V characteristics of an illuminated solar cell with parasitic resistances and bias dependent photocurrent as j=. (1. vm)/(1. +. αv), here the normalized voltage, v and normalized current density j can be represented as v=V/Voc and j=J/Jsc respectively, where Voc is the open circuit voltage and Jsc is the short circuit current density. The model is an equivalent rational function form and useful for design, characterization and calculation of maximum power point voltage. The model is intuitive and lacks the analytical support. In this paper an analytical derivation of the model is presented using the physics based implicit J - V equation. © 2014 Elsevier Ltd.


Das A.K.,Center for Study of Science
Energy Systems | Year: 2014

The power curve of a wind turbine grows exponentially as a function of wind-velocity if the measured wind-velocity varies between the cut-in velocity and the rated velocity. In this study, we propose an empirical, two-parameter explicit model of the power curve for a wind turbine. The model generalizes different turbine power curves and provides an easy estimate to compare various turbine characteristics. The energy analysis of the wind turbine is done using the (proposed) functional relationship and demonstrates how the capacity factor of a wind turbine varies with these empirical factors. © 2014 Springer-Verlag Berlin Heidelberg.

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