Heliostat with integrated image-based tracking controller

Abstract

A system (100) for directing incident sun light to a receiver (150) based on an integral imager (116) is disclosed. The system includes an imager (116) mounted to a reflector (112); a tracking controller (226) coupled to the imager; and one or more actuators (114) connected to the reflector and tracking controller. The tracking controller (226) is configured to receive and process image data fromthe imager (116); determine angular positions of a radiation source and target relative to the mirror normal vector (N) based on the image data; and orient the reflector with the axis bisecting the angular positions of the sun and receiver (150). When the optical axis of the imager is precisely aligned with the vector normal to the reflector, the source and target will be detected as antipodal spots (320, 330) with respect to the center of the imager's field of view, which may be used to effectively track the sun or like object.

Description

technical field [0001] The present invention generally relates to techniques for deploying heliostats to track the sun. In particular, the present invention relates to systems and methods for aiming mirrors or other optical elements using a 2D imager integrated on a heliostat to direct reflected light to a receiver. Background technique [0002] In some solar thermal plants, many heliostats are used to reflect light onto receivers. To account for the sun's motion, the mirrors of each heliostat must be constantly repositioned. Tracking errors in large power plants must be very small to achieve a high concentration at the receiver aperture. However, knowing the position and orientation of the heliostats after they are installed is generally not accurate enough to accurately reflect light to the receiver. A calibration stage is then required to produce better estimates of the position and orientation variables. [0003] For calibration, power plants typically use one of sev...

AI Technical Summary

Problems solved by technology

However, this system poses several practical difficulties

First, the surrounding camera must be located very close to the receiver aperture, thus increasing the chance of damaging the camera if subjected to concentrated flux

Second, each camera must be able to image the entire area (requires very large field of view) and resolve all heliostats (requires very good resolution), which is especially true for areas with very large numbers of small heliostats difficulty

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