Calibration-free hcpv sun tracking strategy

Abstract

When using high concentration photovoltaics modules, sun trackers must meet severe specifications in order to keep sun pointing error within a very small angle. Those required specifications are not only mechanical (misalignments in the structure itself, clearances of the joints, etc.) but also regards the installation (misalignments of the platform with respect to geographical north). These uncertainties are error sources that make necessary to calibrate the system after installation and possibly recalibrate it from time to time because of aging. This paper presents a control strategy that avoids the necessity of any kind of calibration by using, indirectly, the produced electric power as feedback. The control strategy is valid as far as the sun tracker is able to perform movements in the azimuth and elevation coordinates independently. Experimental results with a two axes solar tracker are exposed showing the validity of the proposed control strategy under sunny conditions.