Photovoltaic emulator

With the increasing use of photovoltaics (PV), flexible test-systems for PV testing are growing in importance. This is particularly true for low-cost photovoltaic emulation - hardware devices which replicate the characteristics of a real photovoltaic (PV) panel but can be tuned to emulate different commercially available units and would allow the replication of varying environmental conditions in the laboratory. The scheme presented in this paper is very low-cost, easily expandable, readily interfaced to other control hardware and can emulate a variety of conditions with minimal setting changes. This methodology uses the output voltage of an adjustable linear voltage regulator which is controlled to replicate the characteristic curve of a photovoltaic panel. Its key features are that it uses the non-linearity of a commercial IC to represent the PV panel and bump-less transfer between this non-linear stage and constant current control which is required for low-voltage outputs.