please can you help me about how to calculate ripple current experienced by electrolytic caps that occur just after the diode bridge in an offline SMPS ?
When the diode bridge is conducting......does the electrolytic cap also supply power switch current, or is it just the diode bridge supplying the switch current alone at that time ?
There are two components, summing to the total ripple current. Just assume, that that the high frequent AC current has to be supplied from the capacitor allone. The low frequency (100/120 Hz) current can be determined most accurately from DC voltage waveform, assuming a constant power demand from the converter. The currents have to be square-summed, cause they are orthogonal.