I understand that when there is a low frequency envelope which modulates the high frequency waveform that flows in an electrolytic capacitor then the increased ESR must be considered for the low frequency component. (because as you know, electrolytic capacitor ESR is always higher for the lower frequencies)
….However, is this really true?....for example, consider a 100khz Flyback power supply running constantly for 2000 days. Now consider that for one day it is run at full load, then for the next day it is suddenly switched to run at half load, then suddenly back to full load….etc etc , continuously. So what we have is a modulating envelope in the electrolytic capacitor ripple current that has a period of 1 day. Now, from our theory concerning that ESR is greater for lower frequencies…would we have to consider the increased ESR for the 1 day period component?
I suspect that we would not……however, the 1 day period component is definitely there.
So I suspect that low frequency modulating envelopes of high frequency capacitor ripple current do not actually have to be taken into account in the assessment of the actual ESR. Do you agree?