Explain clearly with the help of suitable figures how the current and Voltage levels of PV modules are increased by interconnecting them.

 Ans: An individual cell produces about one watt of power at about 0.5 V and they are of no practical use. Hence the basic building block for PV applications is a module consisting of a number of pre-wired cells in series, all encased in tough, weather-resistant packages in an area of several square feet. Such an encased panel is called a Solar Module.

Most solar PV panels have 30 to 36 cells connected in series. Each cell produces about 0.5 V in sunlight, so a panel produces 15 V to 18 V. These panels are designed to charge 12-V batteries.

The current depends on the size of each cell, and the solar radiation intensity. Most cells produce a current of 2 A to 3 A in bright sunlight. The current is the same in every cell because the cells are connected in series.

Multiple modules, in turn, can be wired in series to increase voltage and in parallel to increase current, the product of which is power.

An important aspect in PV system design is deciding how many modules should be connected in series and how many in parallel to deliver the required energy. Such combinations of modules are referred to as an array. Figure below shows this distinction between cells, modules, and arrays.