The two steps in photovoltaic energy conversion in solar cells are described using the ideal solar cell, the Shockley solar cell equation, and the Boltzmann constant.
The model will be used to derive the so-called solar cell equation, which is a widely used relation between the electric current density I leaving the solar cell and the voltage V across the converter. For this purpose, we use the relation for generated power P = I ⋅ V and Eq. (127) and we obtain: By using Eqs. (128), (129) we derive:
Here you will learn how to calculate the annual energy output of a photovoltaic solar installation. r is the yield of the solar panel given by the ratio : electrical power (in kWp) of one solar panel divided by the area of one panel. Example : the solar panel yield of a PV module of 250 Wp with an area of 1.6 m2 is 15.6%.
You have learnt previously that the power output of a photovoltaic solar cell is given in watts and is equal to the product of voltage times the current (V x I). The optimum operating voltage of a PV cell under load is about 0.46 volts at the normal operating temperatures, generating a current in full sunlight of about 3 amperes.
The type of solar power produced by a photovoltaic solar cell is called direct current or DC the same as from a battery. Most photovoltaic solar cells produce a “no load” open circuit voltage of about 0.5 to 0.6 volts when there is no external circuit connected.
The basic unit of a photovoltaic system is the photovoltaic cell. Photovoltaic (PV) cells are made of at least two layers of semiconducting material, usually silicon, doped with special additives. One layer has a positive charge, the other negative. Light falling on the cell creates an electric field across the layers, causing electricity to flow.