Photovoltaic (PV) systems make electricity from sunlight, and are built from several important components: Photovoltaic cell:Thin squares, discs, or films of semiconductor material that generate voltage and current when exposed to sun light. Module/Panel:A configuration of PV cells laminated between a clear glazing and an encapsulating substrate. Array:One or more panels wired together for a specific voltage and fastened to amounting structure. Charge controller:Equipment that regulates battery voltage. Battery:A device that chemically stores the direct current (DC) electrical energy. Inverter:An electrical device that changes direct current to alternating current (AC).
Photovoltaic (PV) systems configured for four common systems:-
PV â€“ Direct:This is the simplest and least expensive PV systems which designed for day use only. These systems consist of modules wired directly to a DC appliance, with no storage device. For example the Remote water pumping for a storage tank, Operation of fans, blowers, or circulators to distribute thermal energy for solar water heating systems or ventilation systems.
Stand-Alone system (Off-Grid):This system's basic components include a PV module, charge controller, storage batteries, and inverter to feed the AC appliances,e.g. Solar Street Light, Telecommunication systems in remote sitesâ€¦etc.
Grid-Tied system (On-Grid):This PV systems are connected to the utility grid and do not use battery storage in their design because the utility grid acts as a power reserve.
Grid-Tied with battery backup system:If the utility grid goes down, the inverter in the on-grid Systems automatically shuts off and will not feed electricity back into the grid, so some of these systems are equipped with battery storage to provide power in the event of power loss from the utility grid.