International Intercomparison of Primary Photovoltaic Reference Cell Calibrations With Excellent Agreement

Abstract

This study presents the results of an international intercomparison of primary calibration methods for photovoltaic (PV) reference devices according to IEC 60904‐4. The comparison involves three leading calibration laboratories—PTB, NLR, and AIST—representing independent traceability chains to the International System of Units (SI). Four world PV scale (WPVS) PV reference cells with distinct characteristics (linear, nonlinear, IR‐filtered, and UV‐filtered crystalline silicon devices) are circulated and calibrated using different primary methods, including differential spectral responsivity (DSR), direct sunlight, and solar simulator approaches. The measurand is the short‐circuit current I SC under standard test conditions STC ( I STC ). Calibration results are evaluated using weighted means and E n scores to assess consistency. Despite differing measurement principles and device‐specific challenges, all reported calibration values agree within their stated uncertainties (| E n | < 1). Maximum deviations range from 0.27% to 0.59%, depending on the device type. Observed drifts in two devices are attributed to degradation effects rather than methodological inconsistencies. The results demonstrate a high level of agreement between independent primary calibration methods and confirm the robustness of current traceability chains for PV reference devices.