A solar tracker is a device that orients solar panels, mirrors,
lenses or heliostat toward the sun.
in most of these systems, the need for high efficiencies dictates the use of
devices for sun tracking. Figure 1 shows a conceptual method of efficiency
water extraction using solar power. During the hours of daylight, the solar
collector would produce electricity to pump water from the underground water
table to a reservoir (perhaps on a nearby mountain or hill) and in the early
morning hours, the water would be released into the irrigation system.
One of the most important features of the solar collector is
that the collector dish must track the sun accurately. Therefore, the movement
of the collector dish must be controlled by sophisticated control systems. Figure
2 describes the general philosophy of the sun-tracking system together with
some of the most important components. The basic philosophy of the control
system is that a predetermined desired rate is modified or trimmed by actual
position errors determined by the sun sensor. The controlled ensures that the
tracking collector is pointed toward the sun in the morning and sends a “start
track” command. The controller constantly calculates the sun’s rate for the two
axes of control during the day. The controller uses the sun rate and sun sensor
information as inputs to generate proper motor commands to slew the collector.
Figure : 1
Figure : 2
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