Impedance Spectroscopy of Bifacial Photovoltaic Modules under Outdoor Conditions

Impedance spectroscopy has recently emerged as a promising diagnostic tool for monitoring and assessing the health status of photovoltaic modules, particularly in the context of performance optimization and degradation analysis. Directly derived from the Electrochemical Impedance Spectroscopy widely used for characterization of electrochemical systems, its application to PV modules under real operating conditions remains challenging due to the technique's sensitivity to the intrinsic variability of irradiance and temperature during outdoor testing. This paper investigates the use of impedance spectroscopy on bifacial photovoltaic modules operating outdoor. The study presents the impedance spectra of bifacial photovoltaic modules operating at different configurations, irradiance values and biasing points. In particular, this work investigates the relationship between the impedance spectrum and the irradiance on both the front and rear sides of the bifacial photovoltaic module, and simultaneously provides reference data for real-time monitoring techniques and advanced diagnostic strategies for bifacial photovoltaic modules.