Capacitive tracer design to mitigate incomplete I-V curves in outdoor tests

Abstract

ABSTRACT: The capacitance technique is the most straightforward and low-cost technique to trace the I-V curve of photovoltaic (PV) modules. Nevertheless, the sweep speed and number of samples to measure the I-V curve depend on the device under test (DUT), capacitance size, switching dynamic, lighting conditions, Etc. Therefore, two performance indexes were proposed to evaluate the I-V curve quality. The indexes were estimated from a circuital model considering the transient capacitance charging process as a function of the target irradiance levels and parameters of the DUT and tracer. In this way, a capacitance range is estimated to mitigate the likelihood of measuring incomplete curves in the Isc and Voc regions. Finally, the capacitance sizing design in terms of both indexes for monitoring PV technologies was validated in outdoor tests.