How Solar Panels Work

In a solar photovoltaic power generation system, solar energy is directly converted into electricity. This makes the system more convenient and compact compared to thermal methods of solar conversion.

Solar cell technology is a very fast-growing power generation technology in the world. Because of this, solar cells with conversion efficiencies exceeding 40% have become available.

Photovoltaic cells are also known as solar cells. It is a semiconductor device that uses the photoelectric effect to convert sunlight into direct current. Virtually all solar cells are photodiodes made of semiconductor materials such as silicon. Solar cells work in three steps:

Since the output of a single solar cell is very small, a large number of solar cells are connected to each other to form a solar module. The combination of solar modules is called a panel, and the combination of panels is called a solar cell array. This is done to obtain the desired power output from the photovoltaic system.

When solar cells are connected in series, their voltage increases by as much as the number of cells connected in series. But the current remains the same. When batteries are connected in parallel, the voltage remains constant, the same as one battery, but the current is multiplied. Cells, modules or panels can be connected in parallel only if they have the same voltage. The main components of a solar photovoltaic system are as follows:

The SPV array is connected to the battery. During sunny hours, the panels generate electricity to charge the batteries. But when there is no sunlight or at night, the current will try to flow in the opposite direction, from the battery to the array. This may damage the array. Therefore, to avoid this reverse current flow, blocking diodes are used.

The voltage output of photovoltaic panels varies according to the intensity of sunlight. This causes fluctuations in the load current. A voltage regulator will ensure that voltage fluctuations remain within specified limits.

Since the electricity generated by the photovoltaic array is direct current, an inverter is used to convert it to alternating current so that we can utilize it easily. The inverter unit installed with different protection devices ensures the stability of the system and automatically switches the load and the available power.

These are used to store solar energy. They are an important component in solar photovoltaic systems. The success of solar photovoltaic systems depends largely on battery storage systems.

These are devices that ensure battery charging is done in the correct manner. They control the charging current and protect the battery from overcharging. This is done by constantly monitoring battery current, voltage and temperature.

Depending on the method of use, there are two configurations:

In this system, power is supplied to the load without using any public grid or connection to any other system and can operate autonomously and independently. It is used for backup power which is very expensive to connect to the grid. It can be used to power DC loads or it can be used to power AC loads using an inverter. There are different types of standalone systems. But commonly used is a hybrid stand-alone system.

In a hybrid stand-alone system, one or more sources are used in addition to the PV panels. Sources such as generators, fuel cells, AC power, etc. can be used in conjunction with photovoltaic arrays. Thus reducing dependence on any single source. This also reduces the battery storage capacity and size of the photovoltaic array.

In this system, the electrical energy generated by the photovoltaic array is directly supplied to the grid or AC load. When the generation exceeds the demand of the load, it is provided to the commercial grid. Thus, the system becomes part of a larger technology. In this system, electricity is supplied to the grid when the electricity generated by the PV array exceeds the local load requirements. An energy meter is used to monitor the energy provided.