Optimisation of the I-V measurement scan time through dynamic modelling of solar cells

摘要

High-performance solar cells and photovoltaic modules exhibit high internal capacitance, limiting the speed of their transient responses including the current??voltage characteristics scans. This study proffers a model-based method to obtain optimal scan time during the current??voltage performance characterisation of a solar cell or module while preserving a pre-set accuracy. Static model parameters are extracted from the quasi-static current??voltage characteristic, whereas the capacitive character, modelled by two bias voltage dependent capacitances, is determined from the open-circuit voltage decay measurement. The obtained model is used to calculate the optimal current??voltage curve scan time. Efficacy of the proposed method is demonstrated through test results obtained on three wafer-based solar cells. I??V curve errors determined by the proposed method at different scan times are in good agreement with the measurements. Results show that in order to achieve < 0.5% error in curve fitting, determined scan times of tested crystalline silicon solar cells lie within the range of 3.6??45 ms for constant angle step semiconductor curve tracer. Use of a capacitive-based curve tracer, however, requires approximately twice that time to retain a comparable error.