Tracking strategies

Astronomic strategy

The usual tracking strategy defines the tracker's angle in order to minimize the incidence angle for a given sun's position.

This requires a detailed calculation of the sun's position at each time, an accurate positioning of the tracker's mechanics (tilt and orientation), and specific algorithms for each kind of trackers.

Irradiance optimization strategy

This new strategy determines the orientation according to the best irradiance received by the trackers. This may be different than the previous strategy as the transpositon of the diffuse component is proportional to (1 + cos(i) / 2), where i = tilt angle. Therefore the higher tilt, the less transposed irradiance.

As a consequence, for a fully covered weather, the optimal tracker's position will be horizontal (Phi = 0).

In practice, this strategy may be applied in a very simple way, by putting 2 irradiance sensors on the tracker, separated by a black wall perpendicular to the tracker: the best orientation is obtained when the irradiances on each sensor are equal. The irradiance difference signal may be directly used for feeding the tracking motors.

In the present time, this strategy is only available for one-axis (including unlimited) trackers in PVsyst.

Backtracking strategy

The backtracking strategy aims to avoid mutual shadings between trackers in the morning and the evening.

This is fully explained in the Near shadings part, Backtracking strategy.