Performance Assessment of Photovoltaic Panels Using Impedance Spectroscopy

Technical Report · Tue Oct 15 04:00:00 EDT 2024

DOI:https://doi.org/10.2172/2467554· OSTI ID:2467554

Park, Sung Yeul ^[1]; Agrios, Alexander ^[2]; Ayers, John ^[2]

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1. Univ. of Connecticut, Storrs, CT (United States); University of Connecticut
2. Univ. of Connecticut, Storrs, CT (United States)

The goal of this project was to develop a technique for measuring internal characteristics of a PV module using light modulation under a fixed voltage bias while measuring the resulting alternating current. This technique, light-intensity modulated impedance spectroscopy (LIMIS), has the promise of detecting early signs of panel aging and degradation that could be used for example by solar farm operators to have early warnings to repair or replace panels to maintain reliability of the overall PV array. LIMIS would be complementary with the previously developed electrochemical impedance spectroscopy (EIS), which uses an alternating voltage applied electrically to a solar cell with a similar alternating current measurement. EIS has mostly been developed for individual PV cells rather than whole modules. The project was intended to assess what different information could be revealed by LIMIS, which may in some cases be more scalable to larger modules and potentially more practical to apply in field measurements without needing to electrically disconnect PV modules. We began with small 10 W PV modules and built a testbed capable of oscillating the light intensity with frequencies up to 50 kHz. In parallel, we built a large testbed for testing large 250 W PV modules. Meanwhile, we developed procedures for established measurement techniques: current–voltage (I–V), EIS, and electroluminescence (EL) imaging, where panels are subjected to forward bias while their infrared emission is recorded using a camera modified to be sensitive to IR wavelengths. In addition, we developed protocols for accelerated aging of PV modules in two ways. Thermal cycling from –40°C to +90°C simulates the diurnal temperature cycles on a rooftop. Mechanical stress by dropping a 227 g ball from a height of 1 m simulates damage such as that due to hail impacts.

• Research Organization: Univ. of Connecticut, Storrs, CT (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• DOE Contract Number: EE0010253
• OSTI ID: 2467554
• Report Number(s): DOE-UCONN--EE0010253
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
Degradation
Impedance Spectroscopy
Performance Assessment
Photovoltaic