The power input from the panel is constant under a constant isolation and the power output to the grid is time varying at twice of the grid frequency. Mathematically
Where , , and are the peak voltage, peak current and peak angular frequency
Of the grid and respectively and is the peak instantaneous grid power.
Fig….illustrates the relationships between and . At the steady state, the average value of is equal to . That is
The capacitor acts as a buffer for absorbing the difference between and . Fig. 3 depicts the low-frequency profile of the capacitor voltage varying between and
at a dc value of . Thus
If will increase, and vice versa. as shown in figure…
Consider the time interval and increase from to .