Amongthe materials shown about, most famous is Silicon for its availability, foundfrom the silica sand and purified either in form of monocrystalline orpolycrystalline. Si for its cheapness is mostly used and its pn-junctionbehavior as well as it is conducted at mid-range radiation from sun.
c-Si solarcells have efficiency averaging over 15%. Which means they are capable ofconverting over 15% of solar energy in electrical. Typically, each solar cellis made up of a square having an area of approximately 1 cm2 producespower of about 1.5 W of the voltage 0.6 V, which is too below the leastrequired to operate for applications.
Therefore, they are combined in series tomake a proper standard of voltage. Different sizes and standards are designedby manufacturers according to the applications. Each photovoltaic systemcontains Solar module which is heart of solar PV system.2.1.4 Solar Photovoltaic System Basically, solar system contains,· Photovoltaic cell· Battery backup· Control unit orsolar module· Load· Main supply unit PV cell Battery backup Load Control Unit Main supply Figure5.
TypicalBlock diagram of solar Photovoltaicsystem The PV cell is the main component ofthe system which converts solar energy into electrical energy, which is usuallya series of solar modules mounted on solar panels for larger output power. Itconverts light into direct current, DC power which can be utilized directly forlow power applications and even can be utilized for high power applications by usinginverter and storing the power into the battery for backup. Due to the serial connection ofphotodiodes, if any of the module is stops conducting in case it is shaded andother is producing energy, power will start flowing within the shaded solar moduleand causing over heat and may damage the solar panel, so for its safety thisproblem is prevented by using bypass diodes, even blocking diode is used sothat battery does not drain its power when solar panel is shaded. The solar panel issupported by a mechanical structure or placed such a way that it receivesmaximum possible radiations coming onto the surface of earth, or a solartracking system is designed.