Simple Solar Tracker (SST)

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The SST is a simple, but highly accurate, tracking system to keep photovoltaic panels or other sun energy receivers oriented accurately to obtain highest possible receiver efficiency.

The SST simply consists of small photovoltaic panels, a shadow board, and small double pole-single throw relays to drive the receiver’s aiming motors. The solar panels need only be sized large enough to drive the aiming motors. Two of these photovoltaic panels are needed for each axis to be controlled. To accurately track the sun for all seasons, two axes, elevation and azimuth will need to be provided.
Each photovoltaic panel will be illuminated when the panels are oriented normal to the sun, keeping two small relays energized. As the sun moves with respect to the panels, one panel will become shaded by the shadow-board which lies between them, causing the relay powered by that panel to de-energize. The relays are wired such that when this occurs, the motor turns to re-orient the panels normal to the sun. This function works just as well in controlling elevation as well as azimuth. An added benefit is that precision alignment of the tracking system is not required beyond pointing it in a generally southerly direction, the system will adjust.

Once the sun sets, all the photovoltaic panels stop energizing their respective relays, which engages another relay which can use a small amount of stored energy (in a capacitor or battery) to swing the array to face the east in preparation for the next day.

Further Potential for Product Expansion:
The “reset” relay could be eliminated by the careful application of angled mirrored strips to the east side of the shadow board, oriented such that the morning sun would reflect onto eastern-most panel providing sufficient energy to reorient the tracker toward the sun.

The aiming accuracy of the system can be increased by narrowing the photovoltaic panel strip, or increasing the height of the shadow board.

Everything except the photovoltaic can be easily manufactured anywhere in the world that has access to simple electrical and mechanical technology. It’s possible that many of the components can be sourced from local supplies of spare parts or scavenged hardware. One manufacturing advantage of this design is that ball-screws and gear-boxes are not required for the tracking drive, because simple, direct-drive linear actuators can be manufactured with only four ball bearings and a small dc motor, very similar to the linear actuators available at or .


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  • Name:
    Mark Fuller
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