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3. Photovoltaic Irrigation Systems Components 301

FIGURE 9.2
Scheme of a grid-connected photovoltaic irrigation system with direct pumping.

3. PHOTOVOLTAIC IRRIGATION SYSTEMS COMPONENTS
PV irrigation systems are composed of two main and highly interrelated subsystems,
namely the PV subsystem, which is responsible for supplying the energy required,
and the irrigation subsystem, which demands energy.

3.1 PHOTOVOLTAIC POWER PLANTS
The main components of a PV power plant are the following:
• PV modules
• Solar trackers
• DC to AC inverters or converters

3.1.1 Photovoltaic Modules
The group of PV cells is known as the PV module. PV panels consist of an array of
solar cells connected to form a circuit “in series” to increase the output voltage up to
the desired value. The main function of the PVarray is to produce a DC between its
two terminals when they are illuminated by sunlight (Fig. 9.3).
The ieV performance curve of a common PV module receiving an irradiance of
2
1000 W/m is depicted in the following figure.
Several characteristic points or values can be distinguished on this curve:
• Short-circuit current, I sc : The current that is obtained from the cell when the
voltage at its terminals is 0 V (V ¼ 0).
• Open circuit voltage, V oc : The voltage for which the current drawn from the cell
is zero (i ¼ 0). If the device is kept in an open circuit, it will self-polarize with a