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 transposition of the diffuse component is proportional to \((1 + cos(i) / 2)\), where i is 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.

Wind Stow strategy

The wind stow strategy aims to protect solar panels from damage during high wind events. Wind can cause significant damage to solar panels by creating life forces and twisting moments, resulting in panel breakage, bending or detachment from their mounts.

The wind stow strategy places the solar panels in a stowed position before the arrival of a high wind event. This means tilting the panels at an angle that minimizes their wind profile, so that they are less susceptible to wind-induced forces. The ideal angle of the panels will depend on the specific mounting system used.

For the moment, this strategy is only available when weather files with hourly wind speed data are used, and for tilted axis trackers and horizontal axis N-S trackers.

When the option is activated, the default wind speed threshold that activates the stowing strategy is 12m/s and these stow position is 0°. Users can also define these values as desired.