Datasheet

90E32AS ENHANCED POLY-PHASE HIGH-PERFORMANCE WIDE-SPAN ENERGY METERING IC
Function Description 30 April 2, 2013
Figure-15 Segment Gain Compensation
3.9.2 DELAY/PHASE BASED COMPENSATION
The Channel phase compensation delay can be tuned according to
the measured frequency and current RMS.
• Phi0 is the calibrated delay between the V/I channel (in terms of
2.048Mhz clock cycles)
• PhiF is the delay change per frequency change
• F0 is the nominal frequency,
• PhiIrms is the delay change per current change
• Phi_offset is the offset for segment calibration
• Log(x)= Log
2
(x)*16
If (Irms > Irms0)
PhiIrms = PhiIrms0, Irms_ref = Irms0,
Phi_offset=0
If (Irms1<Irms < Irms0)
PhiIrms= PhiIrms1, Irms_ref = Irms0,
Phi_offset=0
If (Irms < Irms1)
PhiIrms = PhiIrms2, Irms_ref = Irms1,
Implementation Note:
The channel_phi could be computed at the 8Khz rate. The computed
channel_phi (before applied to the delay chain in the decimator) shall be
averaged and updated every 8192 8Khz-samples (about one update per
second). This is to attenuate the fluctuation generated in the computa-
tion when the current is small and avoid frequent updating of the delay,
which is assumed to be a fixed value in the decimator.
PhiIrms0
PhiIrms1
PhiIrms2
Irms0
Irms1
Log(Irms)
Delta-Gain
Delta-Phi
Delta-Gain
Delta-Phi
GainIrms0
GainIrms1
GainIrms2
Phi_offset +
256
))
Irms_ref
Irms
(Log(*PhiIrms
512
F0)-(F*PhiF
Phi0=
iChannel_Ph
++
256
))
Irms0
Irms1
(Log(*PhiIrms1
= Phi_offset