Seven-Point Solar Tracking Control for a Fiber-Optic Daylighting System

Abstract

Abstract A strategy for precise solar tracking has been developed using feedback signals from seven photosensors in conjunction with the operation of an active daylighting system. The tracking system was composed of a microcontroller, two stepper motors, photosensors, a grooves-in Fresnel lens concentrator, and a glass optical fiber cable. A robust control was implemented using cadmium sulfide (CdS) sensors to track the sun’s path precisely from sunrise to sunset. To avoid the cloud effect, two separate sensors were installed apart from the main tracking sensors. The control system was allowed to track the sun’s position if clouds covered the sky continuously for less than approximately 70 min. To analyze the performance of the solar tracker for daylighting applications, a series of experiments were performed in different weather conditions where the accuracy and effectiveness of the present solar tracking control were confirmed.