Limitations of Commercial IV Curve Tracers for Field Evaluation of Modern Photovoltaic Modules
Abstract
This study compares the use of five commercial IV curve tracers—three capacitive and two electronic-load—on high-efficiency bifacial half-cell photovoltaic (PV) modules. Outdoor measurements were performed on three PV modules with different cell technologies and wafer formats: (1) n-type M10, (2) p-type M10, and (3) p-type G12. Capacitive-load IV tracers showed systematic power shortfalls near the maximum-power point on devices with low V/I and/or higher intrinsic (diffusion) capacitance, consistent with transient effects that reduce fill factor. Increasing the effective load capacitance in one unit (parallel reconfiguration) extended the sweep time and markedly improved agreement with the electronic-load reference. A pre-test on the n-type module indicated that sweep times of at least ≥500 ms mitigates sweep-direction hysteresis; the electronic-load IV measurements were therefore used as reference. Overall, results showed that very fast sweeps can distort IV curves and reduce FF, whereas sweep profiles tuned to the device’s V/I and capacitance recover the expected power. Practical implications are that adjustable-capacitance capacitive tracers or programmable electronic loads, coupled with sweep times short enough to limit environmental drift yet long enough to avoid transient bias, enable more reliable field IV testing of new-generation PV modules.
Keywords
Field Measurement, IV Curve Tracer, Outdoor Testing, High-efficiency Bifacial PV modules