ADE7752BARW AD [Analog Devices], ADE7752BARW Datasheet - Page 23

• Manufacturer Part Number: ADE7752BARW
• Description: Polyphase Energy Metering IC with Pulsed Output
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
Example 3
In this example, the ADE7752B is connected to a 3-phase 3-
wire delta service as shown in Figure 21. The total active energy
calculation processed in the ADE7752B can be expressed as
where:
V
phase C, respectively.
I
respectively.
As the voltage and current inputs respect Equations 5 and 6, the
total active power (P) is
For simplification, assume that Φ
V
P then becomes
where:
VAN = V × sin(2π/3).
VBN = V × sin(π/3).
As the LPF on each channel eliminates the 2 ω
the equation, the active power measured by the ADE7752B is
If full-scale ac voltage of ±500 mV peak is applied to the voltage
channels and current channels, the expected output frequency
is calculated as follows:
P
P
F
V
V
V
A
1
A
A
CN
AN
REF
−
=
=
and I
, V
7
= V
(
⎛
⎜
⎝
×
×
VA
+
=
=
=
P
P
P
B
=
⎛
⎜
⎝
, and V
2
. 0
Total Active Power = (V
IC
B
=
=
V
+
+
2
2
=
B
−
2
×
60
2
= V
BN
2
VAN
VBN
2
4 .
×
represent the current on phase A and phase B,
VC
V
V
×
=
×
×
×
V
A
I
Hz
V
AN
I
V
V
B
=
0
)
A
C
×
nominal
B
×
×
×
,
×
×
IA
C
= V. The preceding equation becomes
cos
×
SCF
(
×
×
I
I
I
cos
I
represent the voltage on phase A, phase B, and
IAP
cos
A
B
B
A
cos
I
=
( )
×
×
×
ω
×
A
⎛
⎜
⎝
( )
IB
sin
sin
ω
⎛
⎜
⎝
−
ω
⎛
⎜
⎝
⎛
⎜
⎝
l
=
×
t
sin
ω
sin
l
IAN
l
reference
0 S
t
⎛ π
⎜
⎝
t
⎛ π
⎜
⎝
=
−
l
t
+
⎛ π
⎜
⎝
2
2
3
⎛ π
⎜
⎝
3
3
IC
+
3
2
⎞
× ⎟
⎠
=
2
3
) (
2
3
⎞
× ⎟
⎠
2
⎞
⎟
⎠
+
π
+
3
1 S
=
×
π
+
sin
⎞
⎟
⎠
⎞
⎟
⎠
V
sin
VB
+
V
⎞
⎟
⎠
sin
500
=
BN
(
−
sin
C
ω
value
⎛
⎜
⎝
1
⎛
⎜
⎝
A
−
v
ω
l
2
×
⎛
⎜
⎝
– V
t
×
VC
m
l
2
ω
t
+
2
cos
ω
I
V
A
l
+
t
π
×
) (
l
B
= Φ
C
t
peak
+
×
2
)
⎛
⎜
⎝
V
) × I
3
×
+
×
π
ω
π
3
C
cos
IBP
2
⎞
× ⎟
⎠
l
3
⎞
⎟
⎠
t
B
×
π
2
⎞
⎟
⎠
3
+
ac
= Φ
⎛
⎜
⎝
A
cos
cos
⎞
⎟
⎠
−
ω
⎞
⎟
⎠
+ (V
4
IBN
3
l
=
π
( )
⎛
⎜
⎝
t
ω
C
ω
+
⎞
⎟
⎠
0
l
⎞
⎟
⎠
= 0 and
l
l
t
5 .
2
)
2
B
t
component of
3
π
+
– V
V
⎞
⎟
⎠
4
3
rms
π
C
⎞
⎟
⎠
) × I
⎞
⎟
⎠
B
Rev. PrA | Page 23 of 27
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Note that if the on-chip reference is used, actual output
frequencies can vary from device to device due to reference
tolerance of ±8%.
FREQUENCY OUTPUT CF
The pulse output calibration frequency (CF) is intended for use
during calibration. The output pulse rate on CF can be up to 64×
the pulse rate on F1 and F2. Table 7 shows how the two
frequencies are related, depending on the states of the logic
inputs S0, S1, and SCF. Because of its relatively high pulse rate,
the frequency at this logic output is proportional to the
instantaneous active power. As is the case with F1 and F2, the
frequency is derived from the output of the low-pass filter after
multiplication. However, since the output frequency is high, this
active power information is accumulated over a much shorter
time. Thus, less averaging is carried out in the digital-to-
frequency conversion. The CF output is much more responsive
to power fluctuations with much less averaging of the active
power signal (see Figure 15).
Table 6 shows a complete listing of all maximum output
frequencies when using all three channel inputs.
Table 6: Maximum Output Frequency on F1 and F2
SCF
0
1
0
1
0
1
0
1
Table 7. Maximum Output Frequency on CF
SCF
0
1
0
1
0
1
0
1
Freq
S1
0
0
0
0
1
1
1
1
S1
0
0
0
0
1
1
1
1
=
2
×
S0
0
0
1
1
0
0
1
1
S0
0
1
1
1
0
0
1
1
. 6
181
2
×
F
2.3
4.61
1.15
4.61
5.22
1.15
0.58
0.58
Maximum
Frequency for AC
Inputs (Hz)
0.93
1.86
0.46
1.86
2.10
0.46
0.23
0.23
×
1–7
0
5 .
(Hz)
2
×
×
0
5 .
2
4 .
×
2
. 0
CF Maximum for AC Signals (Hz)
16 × F1, F2 = 14.88
8 × F1, F2 = 14.88
32 × F1, F2 = 14.88
16 × F1, F2 = 29.76
160 × F1, F2 = 336
16 × F1, F2 = 7.36
32 × F1, F2 = 7.36
16 × F1, F2 = 3.68
60
×
2
3
=
. 0
139
Maximum
Frequency for DC
Inputs (Hz)
1.85
3.71
0.93
3.71
4.20
0.93
0.47
0.47
Hz
ADE7752B
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