Optimal design of the dual-axis tracking system used for a PV string platform

Abstract

This work deals with the optimal design of the dual-axis solar tracker used for a PV (photovoltaic) string platform. The solution of the dual-axis mechanism was developed starting from the monoaxis version (for the diurnal movement), which was outlined in a previous paper. With reference to the initial monoaxis mechanism, the diurnal movement subsystem was simplified from a structural point of view; while adding the actuating and motion transmitting mechanisms for adjusting the elevation angle of the panels, the same type of linear actuator is being used for both the movements. The optimization study was carried out in a virtual prototyping environment, through the development of complex digital models (which integrate not only mechanical, actuating, and control components, but also algorithms for the solar radiation modeling), and two major optimization directions are being targeted: The geometric optimization of the mechanism, with the purpose of determining the optimal arrangement of two linear actuators while respecting several design constraints; the optimal design of the tracking program, with the purpose of maximizing the energy gain of the dual-axis system with reference to the equivalent fixed system (without tracking). The physical prototype of the tracking system was developed on the basis of the virtual prototype specifications, the experimental and simulation results, which are quite well correlated (especially in sunny days), proving the performance of the proposed design.