Datasheet

ADE7758 Data Sheet
Rev. E | Page 24 of 72
40 706560555045
0.20
0.15
0.10
0.05
0
–0.05
–0.10
FREQUENCY (Hz)
PHASE (Degrees)
04443-054
respectively. Negative values written to the PHCAL registers
represent a time advance, and positive values represent a time
delay. One LSB is equivalent to 1.2 µs of time delay or 2.4 µs of
time advance with a CLKIN of 10 MHz. With a line frequency
of 60 Hz, this gives a phase resolution of 0.026° (360° × 1.2 µs ×
60 Hz) at the fundamental in the positive direction (delay) and
0.052° in the negative direction (advance). This corresponds to
a total correction range of −3.32° to +1.63° at 60 Hz.
Figure 56 illustrates how the phase compensation is used to
remove a 0.1° phase lead in IA of the current channel from the
external current transducer. To cancel the lead (0.1°) in the
current channel of Phase A, a phase lead must be introduced
into the corresponding voltage channel. The resolution of the
phase adjustment allows the introduction of a phase lead of
0.104°. The phase lead is achieved by introducing a time
advance into VA. A time advance of 4.8 µs is made by writing
−2 (0x7E) to the time delay block (APHCAL[6:0]), thus
reducing the amount of time delay by 4.8 µs or equivalently,
360° × 4.8 µs × 60 Hz = 0.104° at 60 Hz.
Figure 54. Phase Response of the HPF and Phase Compensation
(40 Hz to 70 Hz)
44 565452504846
0.10
0.08
0.06
0.04
0.02
0
–0.02
FREQUENCY (Hz)
PHASE (Degrees)
04443-055
0 100 200 300 400 500 600 700 800 1k900
90
0
10
20
30
40
50
60
70
80
FREQUENCY (Hz)
PHASE (Degrees)
04443-053
Figure 55. Phase Response of HPF and Phase Compensation
(44 Hz to 56 Hz)
Figure 53. Phase Response of the HPF and Phase Compensation
(10 Hz to 1 kHz)