Abstract A portable photovoltaic voltage versus current curve tracer is discussed. The curve tracer employs a capacitive load to provide automatic sweeping of the array voltage. The unit is capable of measuring arrays of up to 10 kW in power but is smaller and lighter than a conventional 2.5 kW dissipative load. The current versus voltage (I-V) plot of a photovoltaic array or module is a powerful diagnostic aid. Many recently built photovoltaic installations are in remote locations, which presents the problem of transporting bulky testing equipment. As photovoltaic power becomes more common, a service industry will be needed to develop and supply portable diagnostic instruments capable of measuring modules or entire arrays. Extensions of the present steady state dissipative methods for read more

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A comparative study of three methods for extracting solar cell parameters of the single-diode lumped-circuit model is presented. The methods compared are the curve-fitting method, an iterative 5-point method and a recently proposed analytical 5-point method. Parameter values were extracted using these three methods from experimental characteristics collected from two silicon cells over a range of illuminations and temperatures. The results show that the curve-fitting method can often give erroneous parameter values and the reasons for the errors are discussed. The 5-point methods are found to be reliable and accurate in situations where the model is a good approximation of cell performance. The analytical 5-point method, however, has the added advantage of simplicity. It is also found read more

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Abstract Series resistance is an important parameter in solar cell design and fabrication. Methods reported in literature for its determination are not suitable for routine use. We describe a simple method for obtaining the series resistance. Universal current-voltage characteristics of the solar cells are also given to illustrate the effects of series and shunt resistance. We also offer an explanation for the often observed drop in efficiency when small area cells are scaled upward. Cells less than 0.25 cm* represent the intrinsic potential of any given structure or diode but do not reflect series resistance effects that must be eliminated with huger area cells and the practical problems of griding to allow for current collection. Download read more

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