Photovoltaic modules are operated as DC devices. But they exhibit complex impedance due to the
solar cell design. Subsequent electronic circuits for electric power co nditioning are designed to match the
input at standard operating conditions. During operation the real part as well as the imaginary part of the
i mpedance of photovoltaic mod ules changes due to ambient conditions such as illumination le vel and
temperature [1].
Generally, the operating voltage of an arr ay is fixed and, as the temperature of the array changes the
operating point I-V shifts [2]. If a partial shadow is cast on the panel, the shadowed cells are reverse biased
by the ill uminated cells. A mismatch due to changes o f the complex impedance can lead to a reduced
performance of the whole power generating system. Hence, for designing such efficient high power
photovoltaic systems a detailed study on AC parameters of solar cells is important. In terrestrial
applications, the solar cell is exposed to temperatures varying from 10C to 50C [1].