Question

Carefully explain how a residential, on-grid PV system works during a full 24 hours period ( explain one day/night cycle)

Answer 1

Let us assume for simplicity that the PV system is without battery storage and it is connected to grid directly after rectification of the DC voltage.

Since system is connected to grid, the AC power feeds to grid throughout the day time , the output Voltage being dependent on the level of radiation in w/m^2.So long as the Sun rays emit about 1Watt/m^2 or above PV cell gives a staedy voltage of 0.58 V throughout the day in open circuit , but output falls at temperatures higher than 25 deg.

To provide higher voltage PV cells are connected in series and in Parallel to increase current in external circuits.

In the evening when sun light drops below 1watt/m^2 , the opencircuit ouptput voltage falls and hence output power level falls steeply to zero and hence we will not be able to feed the Grid.