Characterization of silicon based photovoltaic cells using broadband impedance spectroscopy

The growth in photovoltaic installations makes characterization and condition monitoring essential. In this paper, broadband impedance spectroscopy is implemented for characterization and performance monitoring of silicon solar cells for near real-time operation. An optimized quasi-logarithmic broadband signal is designed to estimate the impedance response of the cells. Electrochemical equivalent circuits of the frequency response are then modelled from the obtained Nyquist plots and the cell parameters are extracted using complex nonlinear least squares. This procedure can be applied for direct estimation of the internal parameters of the silicon solar cells/module at different operating points. Results show that the implemented broadband characterization yields good correlation to the conventional electrochemical impedance spectroscopy at significantly reduced procedural time and equipment cost.