Introduction to Photovoltaic System

A photovoltaic system converts solar radiation to electricity directly. Let us discuss about Off-Grid solutions here. Off-Grid plants are those which store energy in batteries directly without

Major components of any Off-Grid Photovoltaic system are as follows

• Photovoltaic Array

• Chemical Battery Storage

• Power conditioning circuits

A PV Array is made up with solar modules. Every module is composed of solar cells which are connected in series or in parallel to meet the terminal properties of whole generator. The active material inside any solar cell is semiconductor material. Semiconductor materials are materials whose electrical conductivity lies between conductors and insulators. Electrical conductivity of these materials can be controlled by either adding some impurities to them(Doping).

Most common semiconductors are made up of silicon or Germanium. There are three possible arrangement of atoms in any semiconductors.

• Crystalline arrangement

• Polycrystalline arrangement

• Amorphous arrangement

Solar Cells with crystalline arrangements have highest efficiency for converting solar radiations to electric energy and those with amorphous arrangement have least efficiency. The thickness required for absorbing light is much higher for crystalline solids and therefor when amorphous materials like amorphous silicone is used, there is considerable material saving.

The primary purpose of chemical battery storage is used in this system to avoid disruption due to non availability of solar radiation during night and during very rainy or cloudy day.Generally energy generated by PV array is partially stored in these batteries

Finally electricity generated by solar cells are ready to be utilized for running electrical equipment. As per the nature of load , the electric power generated by solar cells is conditioned using DC/DC converters and DC/AC inverters

While use of conventional energy sources has always threatened the international climate goals, solar electricity is cheap, efficient and clean way of fulling growing energy demands.