Run-time detection and correction of heliostat tracking errors

This paper investigates the effect of tracking errors in heliostats used in solar tower power plants and proposes an approach based on low-cost distributed electronics capable of limiting their impact. An analysis carried out through a parallel model sets the specifications for design of a closed-loop solar tracker based on a low-cost six-axis digital e-compass. A proof of concept system is devised to test the accuracy of the proposed strategy. This approach allows the solar tracker to perform a run-time detection and correction of heliostat tracking errors, with an accuracy of about 3mrad for the azimuth angle and less than 2mrad for the altitude angle, thus leading to a higher concentration ratio than with an open-loop solar-tracker.