Hello,
I am calculating residual current from 3 phase sinusoidal ,50 Hz current signal ( Attenuated Sinusoidal signal has been shifted to +VE side by a const dc voltage before feeding to adc i/p) directly using on chip 12 bit ADC(of msp430 series with 25 mhz crystal , -Vref = GND).Three phase currents are accurately measured.But I am getting quite good amount of residual current value( even at 2 Amp current) while 3 phase current are balanced ( both in magnitude & angle).I am using simple vector sum method to get the residual current form ADC count ( r, y, b phases).Samples are taken at a interval of < 200 uSec.Around 256 samples is being taken.
Plz share if you have any algorithm or better technique to resolve this issue.Do I require to check any particular adc settings to look for??
Thanks & regards...
ars.