Research on Tracking Control and Deviation Prediction for Lizard-Type Heliostats in Solar Thermal Power Generation

This study takes the Lizard-type heliostat in tower solar thermal power generation as the research object, this study analyzes its sun-tracking process and establishes a reflection model. Based on solar position calculation methods, parameters of the heliostat's elevation and azimuth angles are derived. Through structural analysis and modeling of the Lizard-type heliostat's motion mechanism combined with PLC control technology, a control methodology suitable for this heliostat type is developed via coordinate transformation and mathematical reasoning. The experimental validation was conducted using a Lizard-type heliostat located at longitude 103\u00b070'48\E and latitude 36\u00b005'76\N. Experimental results demonstrate that under open-loop control, considering base errors and environmental influences, when the base tilts -1.84 mrad and 2.44 mrad along two axes respectively measured by protractor, the heliostat exhibits an azimuth root mean square (RMS) error of 5.293 mrad (0.26\\% error rate) and elevation RMS error of 4.275 mrad (0.2\\% error rate). The results indicate that this algorithm achieves precise sun-tracking with high accuracy despite error impacts, effectively reducing optical losses. Furthermore, a mathematical model for deviation prediction is proposed, which quantifies heliostat tilt errors through geometric optical modeling. This enables pre-calculation and quantification of potential operational deviations, thereby optimizing system efficiency, reducing maintenance costs, and enhancing power generation stability.