How
Photovoltaic
Cells Work


Electricity functions by the flow of electrons. You may recall from school that electrons are the negatively charged particles that surround an atom. Electrons carry a negative charge and, when they are loose, will travel towards a positive charge.


Since electrons are a particle, they can collide with other particles, like sunlight. Photovoltaic cells work by having specially engineered materials that are designed to allow their electrons to be knocked loose when particles of light, called photons, hit them. This causes a flow of electrons, which generates electricity.

Mixing DC
and AC


Since photovoltaic cells work by generating DC, direct current, there needs to be a way to change that power to AC before we can connect it to the grid. Power grids function using AC, alternating current, because it is more efficient to transmit AC over the long transmission lines that connect power plants to their customers.


Since AC alters between negative and positive, there is a rate to that change called the frequency. The frequency is the number of times, per second, that the electrical power flips from negative to positive. This is measured in Hertz (Hz). 60 Hz is a common frequency for power grids, but is not the only one.


This means that not only does there need to be a way to flip the DC solar power back and forth, you also need to be able to regulate the speed to match it to the power grid.

Inverters
and
Conditioners

Engineers have worked on this problem and come up with some pretty ingenious solutions. The two main devices that need to be used are Inverters and Power Conditioners.

Inverters:

These are the devices that flip the DC solar power from negative to positive and then back again. It does this by using a complicated circuit that is capable of managing the switch. The inverter need to be controlled by a power conditioner that will match it to the power of the grid.

Power Conditioners:

These devices are what control the inverters’ rate of change, or frequency, so that it will match that of the power grid. Power conditioners are a vital device because if the inverted solar power frequency does not match the grid precisely, the cells can be overloaded and damage to the grid can occur.