Study on the heliostat tracking correction strategies based on an error-correction model

A more accurate heliostat tracking model is needed because current low cost heliostats have error sources that increase the complexity of the heliostat tracking control system and reduce heliostat tracking accuracy. This paper presents the computational process of the six angular parameters, including tilt angle and tilt azimuth angle of the azimuth axis, initial azimuth angle, dual-axis non-orthogonal angle, initial elevation angle and canting angle of the mirror surface plane relative to the elevation axis, as determined by the authors' tracking error correction model and the Hartley-Meyer solution algorithm. To effectively improve the heliostat tracking accuracy, this paper uses two sets of the six angular parameters from the heliostat tracking test data with segmentation of the daytime at the solar noon. Tracking tests with a beam characterization system (BCS) performed on two heliostats in the DAHAN solar power tower plant showed that the calculated heliostat tracking angles corresponding to these two sets of angular parameters were more accurate and could effectively reduce tracking errors. In order to maximize heliostat tracking accuracy, a preliminary combination of the tracking angle bias strategy and the error-correction model was also successfully conducted in this paper.