Any idea what the power factor of this current waveform is?

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treez

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..Hello,
..It is the mains current waveform into a simulation of a 10W flyback LED driver (mains voltage also shown)
Unfortunately, LTspice doesn't do power factor.
 

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  • pow fac.jpg
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Unfortunately, LTspice doesn't do power factor.
Click to expand...
You mean, it doesn't do it automatically. It's quite easy to get it calculated in LTspice or other SPICE variants, e.g. using .fourier analysis.
 

The attached mains voltage and current gives a power factor of 0.87

V(rms)= 233V, I(RMS) = 0.052A, Average of v.i product over one period = 10.58W

therefore, power factor = 10.58/12.116 = 0.87 ...?
...seems very good for such a 'skewy' looking waveform
 

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  • powfac1.pdf
    1.1 MB · Views: 138

I don't agree very much with your calculation.
I see (in your last pdf file) that also the voltage isn't (perfetct) sinusoidal, the lower part is increasing with time and doesn't follow the sinus shape. Furthermore a non-zero DC is superimposed.
 
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the voltage was programmed to be sine, and looks sine.
I dont see the dc.
yes the current is non sine though.
 

treez said:
The attached mains voltage and current...
Click to expand...
The 1MB(!!!) PDF you attached contains this image:

What is the green trace supposed to be showing? It's certaily not mains voltage, and isn't even a very good representation of full-wave rectified mains voltage.

The amplitude and waveform of both the green and blue traces are constantly changing as well, so whatever they are, this isn't even a steady-state measurement.

Was there any purpose in uploading this other than to waste server space and waste our time and bandwidth when we download it? At least the (sensibly sized) image you showed in post 1 made sense.

treez said:
I dont see the dc.
Click to expand...
You're kidding, right? The green trace doesn't even cross zero - it's positive all the way.
 
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right, I now see your point, I measured it in the wrong place..its actually zero dc level.
as you know pfc ccts have slow feedback loops and take ages to get into steady state
 

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