Boost PFC Measurements?

[abhinand rd]

Hello People,
I am having a circuit that has boost based PFC in it(400V,5A).
i need to measure the power factor and total harmonic distortion.
Is it possible just with measurement of voltage and currents waveforms?
Is so, can anyone tell me the procedure how to do it?

Thanks & Regards

 

[chuckey]

To measure the power factor, you need to measure the angle between the current and the voltage. For total harmonic distortion, you need a "distortion meter" or a very good notch filter to get rid off the 50 (60)HZ component.
Frank

 

[abhinand rd]

Hey Frank,
Thanks for ur reply.
Is it sufficient to measure phase angle between current and voltage to calculate power factor? what if the phase angle is zero but current waveform is distorted?
And also, can u pls elaborate on how to measure THD using notch filter technique?

 

[FvM]

Is it sufficient to measure phase angle between current and voltage to calculate power factor? what if the phase angle is zero but current waveform is distorted?

For non-sinoidal curents, power factor has to be calculated as product of displacement and distortion power factor. https://en.wikipedia.org/wiki/Power_factor

Technically, PF will be usually determined as the ratio of in-phase fundamental current and total RMS current.

The harmonic currents, which have different limit values in power quality standards are mostly measured by DFT methods. See IEC1000-3-2 or EN61000-3-2 for reference.