Datasheet
Table Of Contents
- FEATURES
- GENERAL DESCRIPTION
- FUNCTIONAL BLOCK DIAGRAM
- SPECIFICATIONS
- TIMING CHARACTERISTICS
- ABSOLUTE MAXIMUM RATINGS
- ORDERING GUIDE
- PIN CONFIGURATION
- PIN FUNCTION DESCRIPTIONS
- Typical Performance Characteristics
- TERMINOLOGY
- POWER SUPPLY MONITOR
- ANALOG INPUTS
- ANALOG-TO-DIGITAL CONVERSION
- CURRENT CHANNEL ADC
- VOLTAGE CHANNEL ADC
- ZERO-CROSSING DETECTION
- PERIOD MEASUREMENT
- LINE VOLTAGE SAG DETECTION
- PEAK DETECTION
- TEMPERATURE MEASUREMENT
- PHASE COMPENSATION
- ROOT MEAN SQUARE MEASUREMENT
- ACTIVE POWER CALCULATION
- TOTAL ACTIVE POWER CALCULATION
- ENERGY CALCULATION
- LINE ENERGY ACCUMULATION
- REACTIVE POWER CALCULATION
- TOTAL REACTIVE POWER CALCULATION
- APPARENT POWER CALCULATION
- TOTAL APPARENT POWER CALCULATION
- APPARENT ENERGY CALCULATION
- LINE APPARENT ENERGY ACCUMULATION
- ENERGIES SCALING
- CHECK SUM REGISTER
- SERIAL INTERFACE
- INTERRUPTS
- ACCESSING THE ADE7754 ON-CHIP REGISTERS
- OUTLINE DIMENSIONS
REV. 0
ADE7754
–19–
HPF
–
I
B
*
+
AAPGAIN
LPF2
AWGAIN
AAPOS
+
1
28
I
A
V
A
PHASE A
0
HPF
I
B
*
BAPGAIN
LPF2
BWGAIN
BAPOS
+
1
28
I
B
V
B
PHASE B
HPF
–
I
B
*
+
CAPGAIN
LPF2
CWGAIN
CAPOS
+
1
28
I
C
V
C
PHASE C
0
TOTAL INSTANTANEOUS
POWER SIGNAL
ACTIVE POWER
SIGNAL – P
2752545h
Figure 26. Total Active Power Consumption Calculation
For example, for WATMOD = 1, when all the gains and offsets
corrections are taken into consideration, the formula that is
used to process the active power is
Total Active Power
V
AAPGAIN
I
BAPGAIN
I AAPOS
AWG
V
CAPGAIN
I
BAPGAIN
I CAPOS
CWG
AAB
CCB
=
×+
×−+
×
+
×+
+×+
×−+
×
+
×+
1
2
1
2
1
2
1
2
1
2
1
2
12 12 12
12 12
1212
Depending on the polyphase meter service, an appropriate for-
mula should be chosen to calculate the active power. The
American ANSI C12.10 standard defines the different configu-
rations of the meter. Table II describes which mode should be
chosen for each configuration.
Table II. Meter Form Configuration
ANSI Meter Form WATMOD WATSEL
5S/13S 3-wire Delta 0 3 or 5 or 6
6S/14S 4-wire Wye 1 5
8S/15S 4-wire Delta 2 5
9S/16S 4-wire Wye 0 7
Different gain calibration parameters are offered in the ADE7754
to cover the calibration of the meter in different configurations.
Note that in Mode 0, the APGAIN and WGAIN registers have
the same effect on the end result. In this case, APGAIN regis-
ters should be set at their default value and the gain adjustment
should be made with the WGAIN registers.
ENERGY CALCULATION
As stated earlier, power is defined as the rate of energy flow.
This relationship can be expressed mathematically as
P
dE
dt
=
(7)
where P = power and E = energy.
Conversely energy is given as the integral of power.
E Pdt=
∫
(8)
The ADE7754 achieves the integration of the active power
signal by continuously accumulating the active power signal in
an internal non readable 54-bit energy register. The active
energy register (AENERGY[23:0]) represents the upper 24 bits
of this internal register. This discrete time accumulation or
summation is equivalent to integration in continuous time.
Equation 9 expresses the relationship
EptdtLim p nT T
Tn
==
∫
×
→=
∞
() ( )
00
Σ
(9)
where n is the discrete time sample number and T is the
sample period.