Type of Photovoltaic Systems:
On Grid Systems
On-Grid Photovoltaic System is a system connected to the power grid. It consists of photovoltaic panels and inverters.
The solar panels convert solar energy into Direct Current (DC), while the Inverter converts this to Alternating Current (AC). This step is very necessary as all the home electronic equipment are design to work with AC.
If the system produces more energy than is required by the home, the excess energy enters in the power grid and is subtracted from the energy meter. In case that the house needs more electricity than the panels are producing, this power shortage is taken from the power grid. .
Hybrid Grid Photovoltaic System can be upgraded by adding a battery. This type of connection also requires a special inverter, which can also be connected to the battery. For large solar systems, it is more efficient to use an AC connection. These systems have a higher energy efficiency than DC-connected systems. The photovoltaic inverter directly converts solar energy into AC. All unused surplus energy of the consumer is used to charge the battery. In addition to the AC connection, there is also the DC connection. In this type of connection, solar energy is first used to charge the battery and then converted to AC power by the inverter. Just like with the AC connection, the DC connection also requires a separate inverter, which has a regulator that enables charging the battery. For small systems it is more economical to use this connection, while for large systems is needed more than one controller, significantly increasing costs. For this reason, in large systems an AC connection is used.
Off Grid Photovoltaic System is a stand-alone system, not connected to the power grid. It consists of Photovoltaic Panels, Inverter, Regulator and Battery. The regulator serves to connect the Panels to the Battery. If the system produces more power than is needed at home (usually during lunch time), then excess energy is stored in the Battery. Later, when the home needs more power than the panel is producing (usually at dinner and in the morning), this power outage is taken up by the Battery. Similar to On-Grid systems, Off-Grid systems can also be connected to AC or DC and can also be supported by a generator. AC connection is more convenient for large systems because it has lower cost than DC connection. The inverter automatically starts and stops the generator thus maximizing the use of solar energy.