EVAL-ADE7755ZEB Analog Devices Inc, EVAL-ADE7755ZEB Datasheet - Page 13

• Manufacturer Part Number: EVAL-ADE7755ZEB
• Description: BOARD EVALUATION FOR AD7755
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADE7755ZEB

• Main Purpose: Power Management, Energy/Power Meter
• Embedded: No
• Utilized Ic / Part: ADE7755
• Primary Attributes: Up to 240 VAC, 5 V Supply, Monitors Phase and Neutral Currents
• Secondary Attributes: Exceeds the IEC687/1036 Standard, Less than 0.1% Error, Fault Output
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

NONSINUSOIDAL VOLTAGE AND CURRENT
The active power calculation method also holds true for non-
sinusoidal current and voltage waveforms. All voltage and current
waveforms in practical applications have some harmonic content.
Using the Fourier Transform operation, instantaneous voltage
and current waveforms can be expressed in terms of their
harmonic content.
where:
v(t) is the instantaneous voltage.
V
V
a
where:
i(t) is the instantaneous current.
I
I
β
Using Equation 1 and Equation 2, the active power (P) can be
expressed in terms of its fundamental active power (P1) and
harmonic active power (P
where:
P
and
P
O
h
h
h
1
H
O
h
is the rms value of the current harmonic, h.
is the current dc component.
is the phase angle of the voltage harmonic.
is the phase angle of the current harmonic.
is the active power of the fundamental component:
is the rms value of the voltage harmonic, h.
is the active power of all harmonic components:
is the average voltage value.
P = P
P
Φ
Φ
t i
v
P
) (
1
) (
H
1
h
t
= V
= α
= α
=
=
=
1
h
∑
I
V
1
∞
1
h
+ P
≠
O
1
× I
– β
– β
O
V
+
+
h
H
1
1
h
×
cosΦ
2
I
2
h
×
×
cos
h
∑
1
h
∞
∑
≠
∞
≠
0
0
I
Φ
V
h
H
h
h
×
).
×
sin(
sin
hω
(
hω
t
t
+
+
β
a
h
h
)
)
Rev. A | Page 13 of 20
(1)
(2)
(3)
A harmonic active power component is generated for every
harmonic, provided that the harmonic is present in both the
voltage and current waveforms. The power factor calculation
previously shown is accurate in the case of a pure sinusoid;
therefore, the harmonic active power must also correctly
account for the power factor because it is made up of a series of
pure sinusoids.
Note that the input bandwidth of the analog inputs is 14 kHz
with a master clock frequency of 3.5795 MHz.
ANALOG INPUTS
Channel 1 (Current Channel)
The voltage output from the current transducer is connected
to the ADE7755 at Channel 1. Channel 1 is a fully differential
voltage input. V1P is the positive input with respect to V1N.
The maximum peak differential signal on Channel 1 should be
less than ±470 mV (330 mV rms for a pure sinusoidal signal)
for specified operation. Note that Channel 1 has a programmable
gain amplifier (PGA) with user-selectable gain of 1, 2, 8, or 16
(see Table 5). These gains facilitate easy transducer interfacing.
Figure 24 illustrates the maximum signal levels on V1P and
V1N. The maximum differential voltage is ±470 mV divided by
the gain selection. The differential voltage signal on the inputs
must be referenced to a common mode, for example, AGND.
The maximum common-mode signal is ±100 mV, as shown in
Figure 24.
Table 5. Gain Selection for Channel 1
G1
0
0
1
1
+470mV
–470mV
V
G0
0
1
0
1
CM
Figure 24. Maximum Signal Levels, Channel 1, Gain = 1
V1
Gain
1
2
8
16
DIFFERENTIAL INPUT
±470mV MAX PEAK
±470
±235
±60
±30
Maximum Differential Signal (mV)
COMMON-MODE
±100mV MAX
AGND
V1
V
CM
V1P
V1N
ADE7755