Direct Energy, 2018a

132 6.7 Photodetectors
Solar Panel Array
Block Diagram of solar panel system
Balance of system
Loads
cell
Batteries
Mounting or
tracking
hardware
meter
Concentrator
Power
conditioner
Grid
Module
Solar Panel
Figure 6.16: Components of a solar panel system.
The power conditioning system consists of an inverter which converts
DC electricity to AC and, for grid tied systems, a system to match the phase
of the produced AC power to the phase of the grid. Power conditioning
systems also contain a system to limit the current or voltage to maximize
the power delivered. Also, they include safeguards such as fuses to prevent
injury or damage to equipment. The typical lifetime for the electronics
may be around 10-15 years [73].
6.7 Photodetectors
6.7.1 Types of Photodetectors
Photodetectors are sensors used to convert light, at optical or other nearby
frequencies, to electricity. One way to classify photodetectors is by their
type of active material, which may be a solid or a gas. The rst type of
detectors are semiconductor photodetectors made from solid semiconductor
pn junctions. The choice of semiconductor inuences the wavelengths
of light which can be absorbed because only photons with energy greater
than or equal to the energy gap of the semiconductor can be absorbed. For
example, silicon has an energy gap of 1.11 eV, so it is able to absorb the
photons in both the visible range 1.9 eV