ideal rectifier in series with ideal inductor

AnalogKid

Joined Aug 1, 2013
8,302
I'm not convinced that this gives the correct PF for nonlinear loads. At the very least, in the general case the very notion of "zero crossings" is very ambiguous - there might be a multitude of zero crossings over the course of one cycle and they may not be uniformly spaced). I think the definition of power factor is, fundamentally, the ratio of real power to apparent power.
Yeah, but that "apparent power" thing can be very difficult to determine. I agree with all critiques of the zero-crossing method, but it is what I have to deal with regularly. Any discontinuous current waveform can cause confusion, but for the cap-input supply (linear or switching) our customers are pretty consistent.

Separate from that, anyone know of an online calculator that gives reasonably accurate results for the RMS value of the very messy capacitor-input power supply current waveform?

ak
 

crutschow

Joined Mar 14, 2008
24,324
...................
Separate from that, anyone know of an online calculator that gives reasonably accurate results for the RMS value of the very messy capacitor-input power supply current waveform?
Are you referring to a simulation or a real measurement?
If a real measurement, then the easiest way is to use a digital scope that has built-in RMS calculation capability.
 

AnalogKid

Joined Aug 1, 2013
8,302
Simulation-calculator. Ideally, with inputs like transformer secondary resistance, half/full wave, capacitor size and ESR, load R, L, C, current, watts... Outputs of peak and RMS current, and for desert the phase angle of the positive zero-crossing and pulse width.

ak
 
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